Document:

<PAGE>

                                                                    EXHIBIT 10.1

                        AGREEMENT AND SECOND AMENDMENT TO
                                CREDIT AGREEMENT

         This Agreement and Second Amendment to Credit Agreement (this
"Amendment") dated as of August 16, 2004 among the financial institutions
(collectively, the "Banks") party to the Credit Agreement (as such term is
hereinafter defined); INTEGRATED ELECTRICAL SERVICES, INC. (the "Borrower"), and
BANK ONE, NA, with its main office in Chicago, Illinois, as administrative agent
(in such capacity, the "Administrative Agent") for the Banks;

                              W I T N E S S E T H:

         WHEREAS, the Borrower, the Banks and the Administrative Agent executed
and delivered that certain Credit Agreement (as heretofore amended and
supplemented, the "Credit Agreement") dated as of February 27, 2004;

         WHEREAS, the Borrower is in the process of preparing its financial
statements and as a result cannot provide certain data to the Administrative
Agent in a timely fashion; and

         WHEREAS, the Borrower, the Banks and the Administrative Agent now
desire to amend the Credit Agreement to modify their agreements during the
period that the Borrower cannot deliver such data to the Administrative Agent,
and otherwise amend the Credit Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements, representations and warranties herein set forth, and for other good
and valuable consideration, the receipt and sufficiency of which are
acknowledged, the parties hereby agree as follows:

Section 1. Section 1.1 of the Credit Agreement is hereby amended to add thereto
the following definition, which shall read in its entirety as follows:

                  "Delivery Date" means the later of (a) the date the
         Administrative Agent receives the Borrower's Annual Report on Form 10-K
         for the fiscal year ending September 30, 2004 and Quarterly Report on
         Form 10-Q for the fiscal quarter ending June 30, 2004, in each case as
         filed with the Securities and Exchange Commission, together with
         restatements (if any) of financial statements for all prior dates and
         periods as may be included in either of such filings, or (b) the date
         the Administrative Agent receives the materials required by Section
         5.2(a) with respect to the Borrower's fiscal year ending September 30,
         2004.

Section 2. Each of the following definitions contained in Section 1.1 of the
Credit Agreement is hereby amended to read in its entirety as follows:

                  "Applicable Margin" means, with respect to interest rates and
         letter of credit fees and as of any date of its determination, an
         amount equal to the percentage amount set forth in the table below
         opposite the applicable Total Debt

<PAGE>

         to EBITDA ratio ("X" in the table below), measured as provided in
         Section 5.5(b)(ii), of the Borrower for the four fiscal quarters then
         most recently ended:

<Table>
<Caption>
                                                           Applicable Margin
                         Total Debt                        LIBOR Tranches and          Applicable Margin
                         to EBITDA                        Letter of Credit Fee        Prime Rate Tranche
         -------------------------------------------      --------------------        ------------------
<S>                                                       <C>                         <C>
                        X less than or equal to 2.25              1.75%                        0%
         2.25 less than X less than or equal to 2.75              2.00%                        0%
         2.75 less than X less than or equal to 3.25              2.25%                        0%
         3.25 less than X less than or equal to 3.75              2.50%                      .25%
         3.75 less than X less than or equal to 4.25              2.75%                      .50%
         4.25 less than X                                         3.00%                      .75%
</Table>

                  The foregoing ratio and resulting Applicable Margin shall be
         based upon Schedule C of the most recent Compliance Certificate
         delivered to the Administrative Agent pursuant to Section 5.2(a) or
         Section 5.2(b) (provided that for the period (x) from the date of this
         Agreement until August 16, 2004, the Total Debt to EBITDA ratio shall
         be deemed to be greater than 3.75 but less than 4.25, and the
         Applicable Margin shall be set accordingly, and (y) from August 16,
         2004 until the Delivery Date, the Applicable Margin for LIBOR Tranches
         and the Letter of Credit Fee shall be 3.25% and the Applicable Margin
         for the Prime Rate Tranche shall be 1%).

                  Any adjustments to the Applicable Margin shall become
         effective on the 5th Business Day following the Administrative Agent's
         receipt of a Compliance Certificate; provided, however, that if any
         such Compliance Certificate is not delivered when required hereunder,
         the Applicable Margin shall be deemed to be the maximum percentage
         amount in each table until such Compliance Certificate is received by
         the Administrative Agent.

                  Upon any change in the Applicable Margin, the Administrative
         Agent shall promptly notify the Borrower and the Banks of the new
         Applicable Margin.

                  "Contract Status Report" means a report, in form and substance
         acceptable to the Administrative Agent, detailing the status of each
         contract of any Restricted Entity which contract has (a) a value equal
         to or greater than $7,500,000 or (b) both a value greater than $100,000
         and a projected gross margin of less than 5%.

Section 3. Existing Section 2.2(c)(iii) of the Credit Agreement is hereby
redesignated as Section 2.2(c)(iv) and there is hereby added to the Credit
Agreement a new Section 2.2(c)(iii), which shall read in its entirety as
follows:

                  (iii) Notwithstanding anything in the Credit Documents to the
         contrary, at no time shall the sum of (A) the Revolving Loan plus (B)
         the Letter of Credit Exposure (net of any cash collateral then held in
         the Letter of Credit Collateral Account) plus (C) the Term Loan plus
         (D) the Swing Line Loan be greater than the numerator of the ratio
         computed pursuant to Section 5.5(e), as reflected in the

<PAGE>

         most recent information delivered to the Administrative Agent; and if
         such sum shall ever exceed such numerator, then the Borrower shall
         immediately prepay the Revolving Loan, the Term Loan and the Swing Line
         Loan in at least the amount of such excess (or, if the Revolving Loan,
         the Term Loan and the Swing Line Loan have been paid in full, the
         Borrower shall provide cash collateral to be held in the Letter of
         Credit Collateral Account in an amount at least equal to such excess).

Section 4. The first sentence of Section 2.3(g)(i) of the Credit Agreement is
hereby amended to read in its entirety as follows:

         If the Borrower is required to deposit funds in the Letter of Credit
         Collateral Account pursuant to Section 2.2(c)(iii), 2.3(d) or 6.4, then
         the Borrower and the Administrative Agent shall establish the Letter of
         Credit Collateral Account, and the Borrower shall execute any documents
         and agreements, including the Administrative Agent's standard form
         assignment of deposit accounts, that the Administrative Agent
         reasonably requests in connection therewith to establish the Letter of
         Credit Collateral Account and grant the Administrative Agent a first
         priority security interest in such account and the funds therein.

Section 5. Pursuant to Section 5.2(m) of the Credit Agreement, the
Administrative Agent hereby requests, and the Borrower agrees to deliver, the
following information for each calendar month as soon as available, and in any
event within 25 days after the end of each such month:

                  (a) A Contract Status Report;

                  (b) The aggregate consolidated cash balance of the Borrower
and its Subsidiaries, together with a reconciliation to the prior month;

                  (c) The contract backlog of the Borrower and its Subsidiaries
as of the end of such month, including the estimated gross margin percentage of
such contracts; and

                  (d) An aging of all accounts receivable of the Borrower and
its Subsidiaries, including detail as to the identities of the account debtor
and the account obligee with respect to (1) each account receivable in excess of
$5,000,000 and (2) each account obligee with aggregate accounts receivable in
excess of $10,000,000;

provided that (x) the Borrower shall not be obligated to deliver such
information pursuant to this request after the Delivery Date; (y) the
Administrative Agent or the Majority Banks may request different or additional
information at any time (before or after the Delivery Date) pursuant to Section
5.2(m) of the Credit Agreement, and (z) the Administrative Agent or the Majority
Banks may request the same information after the Delivery Date.

         Section 6. Waiver, Suspension and Deferral of Certain Covenants.

                  (a) Notwithstanding the provisions of Section 5.2 of the
Credit Agreement to the contrary, the Borrower shall furnish to the
Administrative Agent as soon as possible, and in

<PAGE>

any event by December 15, 2004, the materials required by Section 5.2(a) of the
Credit Agreement with respect to the Borrower's fiscal year ending September 30,
2004.

                  (b) The Borrower has breached the Credit Agreement by failing
to provide the materials required by Section 5.2(b) of the Credit Agreement for
the fiscal quarter of the Borrower ending June 30, 2004; such breach is referred
to herein as the "Specified Breach." The Administrative Agent and the Majority
Banks hereby waive the Specified Breach; provided that this waiver shall
terminate upon the earlier of December 15, 2004 or the date that the Borrower
receives notice (a "Default Notice") from the Trustee (the "Trustee") with
respect to the Senior Subordinated Notes, or from the holders of at least 25% in
aggregate principal amount of the Senior Subordinated Notes, of a default in the
performance, or breach, of any covenant or agreement of the Borrower under the
Senior Subordinated Note Indenture. The Borrower agrees that it will promptly
notify the Administrative Agent if the Borrower receives a Default Notice. The
Administrative Agent, as representative of the holders of the "Designated Senior
Indebtedness" (as such term is defined in the Senior Subordinated Note
Indenture) reserves the right (and the Borrower agrees that the Administrative
Agent has such right) to give a notice (a "Non-payment Default Notice") of a
"Non-payment Default" (as such term is defined in the Senior Subordinated Note
Indenture) with respect to the Specified Breach to the Trustee at any time after
the earlier of the Borrower's receipt of a Default Notice or December 15, 2004,
and the Majority Banks hereby direct the Administrative Agent to deliver a
Non-payment Default Notice to the Trustee no later than 25 days after the date
of any Default Notice, unless such Default Notice is withdrawn or such default
or breach has been waived, in each case to the satisfaction of the
Administrative Agent, before the expiration of such 25-day period.

                  (c) The obligations of the Borrower to provide the materials
required by Section 5.2(f) of the Credit Agreement are hereby suspended until
the Delivery Date.

                  (d) The obligations of the Borrower to comply with Section 5.5
of the Credit Agreement are hereby suspended until the Delivery Date; provided
that after the Delivery Date, compliance with Section 5.5 of the Credit
Agreement shall be measured by the financial information then available to the
Administrative Agent (e.g., a breach of Section 5.5 would exist on and after the
Delivery Date if the financial information then available to the Administrative
Agent indicated that the Borrower had breach a provision of such Section as of
September 30, 2004).

         Section 7. From the date hereof through the Delivery Date, Section
5.5(e) of the Credit Agreement is hereby to read in its entirety as follows:

                  (e) Asset Coverage Ratio. As of the last day of each calendar
         month, the Borrower shall not permit the ratio of (1) 60% (for the
         months of July through September, 2004) or 65% (for the months of
         October and November, 2004) of consolidated Unbonded Accounts
         Receivable to (2) the sum of (i) the Revolving Loan plus (ii) the
         Letter of Credit Exposure plus (iii) the Term Loan plus (iv) the Swing
         Line Loan to be less than 1.00 to 1. Compliance with this paragraph (e)
         shall be determined in a report, duly certified by a Responsible
         Officer of the Borrower and delivered no later than 25 days after the
         end of the relevant calendar month.

<PAGE>

         Section 8. Section 5.9(a) is hereby amended to delete exception (ii)
thereto until the Delivery Date; after the Delivery Date, Section 5.9(a)(ii) is
hereby amended to read in its entirety as follows:

                  (ii) The Borrower or any Subsidiary of the Borrower may make
         any Acquisition (by purchase or merger) provided that (A) the Borrower
         or such Subsidiary of the Borrower is the acquiring or surviving
         entity, (B) the aggregate of all consideration (other than common stock
         of the Borrower) paid by the Restricted Entities in connection with all
         Acquisitions during any fiscal year does not exceed $25,000,000, (C) no
         Default has then occurred and is continuing; (D) assuming such
         Acquisition had been made on the last day of the immediately preceding
         fiscal quarter, (1) the Total Debt to EBITDA ratio, as measured in
         accordance with Section 5.5(b)(ii), would have been no greater than
         3.50 to 1 and (2) no Default (including but not limited to any Default
         under Section 5.5) would have occurred as of the last day of such
         quarter, and (E) the acquired assets are in substantially the same
         business as the Borrower.

         Section 9. Section 5.10 of the Credit Agreement is hereby amended to
delete the proviso thereto until the Delivery Date.

         Section 10. Section 6.1(g) of the Credit Agreement is hereby amended to
read in its entirety as follows:

                  (g) Material Agreement Default; Material Plan Event; Surety
         Bond Demand. (i) There shall occur any breach by any Restricted Entity
         of any contract or agreement which breach could reasonably be expected
         to cause a Material Adverse Change and such breach is not cured within
         the applicable grace period, if any; (ii) there shall occur or exist an
         event with respect to any Plan which could in the sole judgment of the
         Administrative Agent reasonably be expected to have a Material Adverse
         Change, or (iii) there shall occur any breach by any Restricted Entity
         of any contract or agreement with the issuer of a Surety Bond pursuant
         to which such Surety Bond was issued and such breach is not cured
         within the applicable grace period, if any;

         Section 11. Conditions. This Amendment shall not become effective until
(a) it has been executed and delivered by the Borrower and the Majority Banks;
(b) the Borrower shall have delivered to the Administrative Agent a certificate
of the Secretary or an Assistant Secretary as to the resolutions of the Board of
Directors of the Borrower authorizing the execution and delivery of this
Amendment; (c) the Borrower shall have paid to the Administrative Agent, for the
account of each Bank executing and delivering this Amendment before 5:00 p.m.,
Houston time, on September 3, 2004, an amendment fee at the rate (which shall be
the same for all such Banks) heretofore established by the Administrative Agent
and the Borrower, and (d) the Administrative Agent shall have received such
other documents and instruments as it may reasonably request; provided, however,
that if all of such conditions are not satisfied by 5:00 p.m., Houston time, on
September 3, 2004, then this Amendment shall be of no force or effect.

<PAGE>

         Section 12. Representations True; No Default. The Borrower represents
and warrants that the representations and warranties contained in the Credit
Documents are true and correct in all material respects on and as of the date
hereof as though made on and as of such date. The Borrower hereby certifies that
no event has occurred and is continuing which constitutes a Default or an Event
of Default.

         Section 13. Ratification. Except as expressly amended hereby, the Loan
Documents shall remain in full force and effect. The Credit Agreement, as hereby
amended, and all rights and powers created thereby or thereunder and under the
other Credit Documents are in all respects ratified and confirmed and remain in
full force and effect.

         Section 14. Definitions and References. Any term used herein that is
defined in the Credit Agreement shall have the meaning therein ascribed to it.
The terms "Agreement" and "Credit Agreement" as used in the Credit Documents or
any other instrument, document or writing furnished to the Administrative Agent
or any Bank by the Borrower and referring to the Credit Agreement, shall mean
the Credit Agreement as hereby amended.

         Section 15. Miscellaneous. This Amendment (a) shall be binding upon and
inure to the benefit of the Borrower, the Banks, the Administrative Agent and
their respective successors, assigns, receivers and trustees (but the Borrower
shall not assign its rights hereunder without the express prior written consent
of the Required Lenders); (b) may be modified or amended only by a writing
signed by the party against whom the same is to be enforced; (c) may be executed
in several counterparts, and by the parties hereto on separate counterparts, and
each counterpart, when so executed and delivered, shall constitute an original
agreement, and all such separate counterparts shall constitute but one and the
same agreement, and (e) together with the other Credit Documents, embodies the
entire agreement and understanding between the parties with respect to the
subject matter hereof and supersedes all prior agreements, consents and
understandings relating to such subject matter.

         THE CREDIT DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES
AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT
ORAL AGREEMENTS OF THE PARTIES.

         THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed by their respective authorized officers as of the day and year
first above written.

                                       BORROWER:

                                       INTEGRATED ELECTRICAL SERVICES, INC.

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       BANKS:

                                       BANK ONE, NA

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       U.S. BANK NATIONAL ASSOCIATION

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       BANK OF SCOTLAND

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       LaSALLE BANK NATIONAL ASSOCIATION

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

<PAGE>

                                       WELLS FARGO BANK, N.A.

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       SOUTHWEST BANK OF TEXAS, N.A.

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       FIRST AMERICAN BANK, SSB HOUSTON

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       ALLIED IRISH BANK, P.L.C.

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       AIB DEBT MANAGEMENT LIMITED

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       REGIONS BANK

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       FIRST BANK & TRUST

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

<PAGE>

                                       HIBERNIA NATIONAL BANK

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                       RZB FINANCE LLC

                                       By:
                                          --------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------<PAGE>
                                                                     EXHIBIT 4.2

                                                                  EXECUTION COPY
================================================================================

                          FOURTH SUPPLEMENTAL INDENTURE

                                     BETWEEN

                         DIAMOND OFFSHORE DRILLING, INC.

                                       AND

                               JPMORGAN CHASE BANK

                  (FORMERLY KNOWN AS THE CHASE MANHATTAN BANK),

                                   AS TRUSTEE

                                   DATED AS OF

                                 AUGUST 27, 2004

================================================================================

<PAGE>

                                TABLE OF CONTENTS

<Table>
                                                           ARTICLE ONE

                                                          THE 2014 NOTES
<S>                     <C>                                                                            <C>
Section 101             Designation of 2014 Notes; Establishment of Form................................2
Section 102             Transfer and Exchange...........................................................3
Section 103             Amount.........................................................................10
Section 104             Regular Interest...............................................................10
Section 105             Liquidated Damages.............................................................10
Section 106             Denominations..................................................................10
Section 107             Place of Payment...............................................................10
Section 108             Redemption.....................................................................11
Section 109             Stated Maturity................................................................11
Section 110             Discharge of Liability on 2014 Notes...........................................11
Section 111             Other Terms of 2014 Notes......................................................11

                                                           ARTICLE TWO

                                                   AMENDMENTS TO THE INDENTURE

Section 201             Amendments Applicable Only to 2014 Notes.......................................11
Section 202             Definitions....................................................................11
Section 203             Registration, Registration of Transfer and Exchange............................15
Section 204             Mutilated, Destroyed, Lost and Stolen Securities...............................16
Section 205             Amendment of Article Four of the Indenture.....................................16
Section 206             Amendment to Section 501 of the Indenture......................................17
Section 207             Reports by Company.............................................................18
Section 208             Amendment to Section 801 of the Indenture......................................19
Section 209             Amendment to Article Ten of the Indenture......................................19

                                                           ARTICLE THREE

                                                      MISCELLANEOUS PROVISIONS

Section 301             Integral Part..................................................................22
Section 302             General Definitions............................................................23
Section 303             Adoption, Ratification and Confirmation........................................23
Section 304             Counterparts...................................................................23
Section 305             Governing Law..................................................................23
Section 306             Conflict of any Provision of Indenture with Trust
                        Indenture Act of 1939..........................................................23
Section 307             Effect of Headings.............................................................23
</Table>

<PAGE>

<Table>
<S>                     <C>                                                                            <C>
Section 308             Severability of Provisions.....................................................23
Section 309             Successors and Assigns.........................................................24
Section 310             Benefit of Fourth Supplemental Indenture.......................................24
Section 311             Acceptance by Trustee..........................................................24

ANNEX A
Exhibit B-1
Exhibit B-2
</Table>

                                       ii
<PAGE>

                         DIAMOND OFFSHORE DRILLING, INC.

                          FOURTH SUPPLEMENTAL INDENTURE

         THIS FOURTH SUPPLEMENTAL INDENTURE, dated as of August 27, 2004,
between Diamond Offshore Drilling, Inc., a Delaware corporation (the "Company"),
and JPMorgan Chase Bank (formerly known as The Chase Manhattan Bank), a banking
corporation organized and existing under the laws of the State of New York (the
"Trustee").

                                   WITNESSETH

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an Indenture, dated as of February 4, 1997 (the "Indenture"), providing
for the issuance from time to time of its debentures, notes, bonds or other
evidences of indebtedness (hereinafter called "Securities") in one or more fully
registered series;

         WHEREAS, Section 901(5) of the Indenture provides that the Company and
the Trustee may from time to time enter into one or more indentures supplemental
thereto to establish the form or terms of Securities of a new series;

         WHEREAS, Sections 901(2) and 901(7) of the Indenture permit the
execution of supplemental indentures without the consent of any Holders to add
to the covenants of the Company for the benefit of, and to add any additional
Events of Default with respect to, all or any series of Securities;

         WHEREAS, Section 301 of the Indenture provides that the Company may
enter into supplemental indentures to establish the terms and provisions of a
series of Securities issued pursuant to the Indenture;

         WHEREAS, the Company desires to issue 5.15% Senior Notes due September
1, 2014 (the "2014 Notes"), a new series of Security, the issuance of which was
authorized by resolution of the Board of Directors of the Company, dated August
23, 2004;

         WHEREAS, the Company, pursuant to the foregoing authority, proposes in
and by this Fourth Supplemental Indenture to supplement and amend in certain
respects the Indenture insofar as it will apply only to the 2014 Notes (and not
to any other series); and

         WHEREAS, all things necessary have been done to make the 2014 Notes,
when executed by the Company and authenticated and delivered hereunder and duly
issued by the Company, the valid obligations of the Company, and to make this
Fourth Supplemental Indenture a valid agreement of the Company, in accordance
with their and its terms.

<PAGE>

         NOW THEREFORE:

         In consideration of the premises provided for herein, the Company and
the Trustee mutually covenant and agree for the equal and proportionate benefit
of all Holders of the 2014 Notes as follows:

                                   ARTICLE ONE

                                 THE 2014 NOTES

Section 101 Designation of 2014 Notes; Establishment of Form.

         There shall be a series of Securities designated "5.15% Senior Notes
due September 1, 2014" of the Company, and the form thereof shall be
substantially as set forth in Annex A hereto, which is incorporated into and
shall be deemed a part of this Fourth Supplemental Indenture, with such
appropriate insertions, omissions, substitutions and other variations as are
required or permitted by the Indenture, and may have such letters, numbers or
other marks of identification and such legends or endorsements placed thereon as
may be required to comply with the rules of any securities exchange or as may,
consistently herewith, be determined by the officers of the Company executing
such 2014 Notes, as evidenced by their execution of the 2014 Notes.

                  (a) Restricted Global Securities. All of the 2014 Notes are
initially being offered and sold to either (i) qualified institutional buyers as
defined in Rule 144A (collectively, "QIBs" or individually a "QIB") in reliance
on Rule 144A under the Securities Act, or (ii) outside the United States to
non-U.S. persons in reliance on Regulation S under the Securities Act, and shall
be issued initially in the form of one or more Notes in registered, global form
without interest coupons, with a restrictive legend as set forth in Annex A
hereto (collectively, the "Restricted Global Securities"). The Restricted Global
Securities shall be deposited on behalf of the purchasers of the 2014 Notes
represented thereby with the Trustee, at its Corporate Trust Office, as
Securities Custodian for the depositary, The Depository Trust Company (the
"DTC") (such depositary, or any successor thereto, being hereinafter referred to
as the "Depositary"), and registered in the name of its nominee, Cede & Co.,
and, in the case of the 2014 Notes held in accordance with Regulation S,
registered in the name of the Depositary or its nominees, in each case for
credit to an account of a direct or indirect participant in the DTC (including,
if applicable, Euroclear System or Clearstream Banking Luxembourg), duly
executed by the Company and authenticated by the Trustee as hereinafter
provided. The aggregate principal amount of a Restricted Global Security may
from time to time be increased or decreased by adjustments made on the records
of the Securities Custodian as hereinafter provided, subject in each case to
compliance with the Applicable Procedures. Prior to the expiration of the
Restricted Period, beneficial interests in the Regulation S Restricted Global
Security may only be held by non-U.S. persons, unless exchanged for interests in
the Restricted Global Securities in accordance with transfer and certification
requirements.

                  (b) Institutional Accredited Investor Securities. Except as
provided in this Section 101 or Section 102, owners of beneficial interests in
Global Securities will not be entitled to receive physical delivery of
Certificated Securities. Securities offered and sold within

                                       2
<PAGE>

the United States to institutional accredited investors as defined in Rule
501(a)(1), (2), (3) and (7) under the Securities Act ("Institutional Accredited
Investors") shall be issued, initially in the form of Certificated Securities,
duly executed by the Company and authenticated by the Trustee as hereinafter
provided.

                  (c) Global Securities in General. Each Global Security shall
represent such of the Outstanding 2014 Notes as shall be specified therein and
each shall provide that it shall represent the aggregate principal amount of
Outstanding 2014 Notes from time to time endorsed thereon and that the aggregate
principal amount of Outstanding 2014 Notes represented thereby may from time to
time be reduced or increased, as appropriate, to reflect exchanges or
redemptions of such 2014 Notes. Any endorsement of a Global Security to reflect
the amount of any increase or decrease in the principal amount of Outstanding
2014 Notes represented thereby shall be made by the Securities Custodian in
accordance with the standing instructions and procedures existing between the
Depositary and the Securities Custodian.

                  Neither any members of, or participants in, the Depositary
("Agent Members") nor any other Persons on whose behalf Agent Members may act
shall have rights under this Indenture with respect to any Global Security held
in the name of the Depositary or any nominee thereof, or under the Global
Security, and the Depositary (including, for this purpose, its nominee) may be
treated by the Company, the Trustee and any agent of the Company or the Trustee
as the absolute owner and Holder of such Global Security for all purposes
whatsoever. Notwithstanding the foregoing, nothing herein shall (A) prevent the
Company, the Trustee or any agent of the Company or the Trustee from giving
effect to any written certification, proxy or other authorization furnished by
the Depositary or (B) impair, as between the Depositary, its Agent Members and
any other Person on whose behalf an Agent Member may act, the operation of
customary practices governing the exercise of the rights of a Holder of any 2014
Notes.

                  (d) Certificated Securities. Certificated Securities shall be
issued only under the limited circumstances provided in Section 101(b),
102(a)(1) and 102(b) hereof.

                  (e) Paying Agent. The Company shall maintain an office or
agency where 2014 Notes may be presented for payment ("Paying Agent"). The
Company shall enter into an appropriate agency agreement with a Paying Agent.
The agreement shall implement the provisions of this Indenture that relate to
such agent. The Company shall notify the Trustee of the name and address of any
such agent. If the Company fails to maintain a Paying Agent, the Trustee shall
act as such and shall be entitled to appropriate compensation therefor pursuant
to Section 607. The Company or any Subsidiary or an Affiliate of either of them
may act as Paying Agent. The Company initially appoints the Trustee as Paying
Agent in connection with the 2014 Notes.

Section 102 Transfer and Exchange.

                  (a) Transfer and Exchange of Global Securities.

                      (1) Except as provided in Section 102(b), Certificated
           Securities shall be issued in exchange for interests in the Global
           Securities only if (x) the Depositary

                                       3
<PAGE>

           notifies the Company that it is unwilling or unable to continue as
           depositary for the Global Securities or if it at any time ceases to
           be a "clearing agency" registered under the Exchange Act if so
           required by applicable law or regulation and a successor depositary
           is not appointed by the Company within 90 days, (y) the Company at
           any time and in its sole discretion determines not to have the 2014
           Notes represented by a Global Security, or (z) an Event of Default
           has occurred and is continuing. In each case, the Company shall
           execute, and the Trustee shall, upon receipt of a Company Order
           (which the Company agrees to deliver promptly), authenticate and
           deliver Certificated Securities in an aggregate principal amount
           equal to the principal amount of such Global Securities in exchange
           therefor. Only Restricted Certificated Securities shall be issued in
           exchange for beneficial interests in Restricted Global Securities,
           and only Unrestricted Certificated Securities shall be issued in
           exchange for beneficial interests in Unrestricted Global Securities.
           Certificated Securities issued in exchange for beneficial interests
           in Global Securities shall be registered in such names and shall be
           in such authorized denominations as the Depositary, pursuant to
           instructions from its direct or indirect participants or otherwise,
           shall instruct the Trustee. The Trustee shall deliver or cause to be
           delivered such Certificated Securities to the persons in whose names
           such Securities are so registered. Such exchange shall be effected in
           accordance with the Applicable Procedures. Nothing herein shall
           require the Trustee to communicate directly with beneficial owners,
           and the Trustee shall in connection with any transfers hereunder be
           entitled to rely on instructions received through the registered
           Holder.

                      In the event that Certificated Securities are issued in
           exchange for beneficial interests in Global Securities in accordance
           with the foregoing paragraph and, thereafter, the events or
           conditions specified in this Section 102(a)(1) which required such
           exchange shall have ceased to exist, the Company shall mail notice to
           the Trustee and to the Holders stating that Holders may exchange
           Certificated Securities for interests in Global Securities by
           complying with the procedures set forth in this Indenture and briefly
           describing such procedures and the events or circumstances requiring
           that such notice be given.

                      (2) Notwithstanding any other provisions of this Indenture
           other than the provisions set forth in Section 102(a)(1) hereof, a
           Global Security may not be transferred, except as a whole by the
           Depositary to a nominee of the Depositary or by a nominee of the
           Depositary to the Depositary or another nominee of the Depositary or
           by the Depositary or any such nominee to a successor Depositary or a
           nominee of such successor Depositary. Nothing in this Section
           102(a)(2) shall prohibit or render ineffective any transfer of a
           beneficial interest in a Global Security effected in accordance with
           the other provisions of this Section 102.

                                       4
<PAGE>

                  (b) Restrictions on Transfer of a Beneficial Interest in a
Global Security for a Certificated Security. A beneficial interest in a Global
Security may not be exchanged for a Certificated Security except upon
satisfaction of the requirements set forth below. Upon receipt by the Trustee of
a request in the form satisfactory to the Trustee from the Depositary or its
nominee on behalf of a person having a beneficial interest in a Global Security
to register the transfer of all or a portion of such beneficial interest in
accordance with Applicable Procedures for a Certificated Security, together
with:

                           (1) in the case of a request to register the transfer
                  of a beneficial interest in a Restricted Global Security, a
                  certificate (a "Transfer Certificate"), in substantially the
                  form set forth in Exhibit B-1, and a certification in
                  substantially the form set forth in Exhibit B-2, that such
                  beneficial interest in the Restricted Global Security is being
                  transferred to an Institutional Accredited Investor;

                           (2) written instructions to the Trustee to make, or
                  direct the Security Registrar to make, an adjustment on its
                  books and records with respect to such Global Security to
                  reflect a decrease in the aggregate principal amount of the
                  2014 Notes represented by the Global Security, such
                  instructions to contain information regarding the Depositary
                  account to be credited with such decrease; and

                           (3) if the Company or the Trustee so requests, a
                  customary opinion of counsel, certificates and other
                  information reasonably acceptable to them as to the compliance
                  with the restrictions set forth in the legend described in
                  Section 102(f)(1),

           then the Trustee shall cause, or direct the Security Registrar to
           cause, in accordance with the standing instructions and procedures
           existing between the Depositary and the Security Registrar, the
           aggregate principal amount of 2014 Notes represented by the Global
           Security to be decreased by the aggregate principal amount of the
           Certificated Security to be issued, shall authenticate and deliver
           such Certificated Security and shall debit or cause to be debited to
           the account of the Person specified in such instructions a beneficial
           interest in the Global Security equal to the principal amount of the
           Certificated Security so issued.

                  (c) Transfer and Exchange of Certificated Securities. When
Certificated Securities are presented by a Holder to a Security Registrar with a
request:

                      (1) to register the transfer of the Certificated
           Securities to a person who will take delivery thereof in the form of
           Certificated Securities only; or

                      (2) to exchange such Certificated Securities for an equal
           principal amount of Certificated Securities of other authorized
           denominations,

                                       5
<PAGE>

such Security Registrar shall register the transfer or make the exchange as
requested; provided, however, that the Certificated Securities presented or
surrendered for register of transfer or exchange:

                      (1) shall be duly endorsed or accompanied by a written
           instrument of transfer in accordance with the fifth paragraph of
           Section 305 of the Indenture; and

                      (2) in the case of a Restricted Certificated Security,
           such request shall be accompanied by the following additional
           information and documents, as applicable:

                           (A) if such Restricted Certificated Security is being
                  delivered to the Security Registrar by a Holder for
                  registration in the name of such Holder, without transfer, or
                  such Restricted Certificated Security is being transferred to
                  the Company or a Subsidiary of the Company, a certification to
                  that effect from such Holder (in substantially the form set
                  forth in the Transfer Certificate);

                           (B) if such Restricted Certificated Security is being
                  transferred to a person the Holder reasonably believes is a
                  QIB in accordance with Rule 144A or pursuant to an effective
                  registration statement under the Securities Act, a
                  certification to that effect from such Holder (in
                  substantially the form set forth in the Transfer Certificate);

                           (C) if such Restricted Certificated Security is being
                  transferred to an Institutional Accredited Investor, a
                  certification to that effect from such Holder (in
                  substantially the form set forth in the Transfer Certificate),
                  a certification from the Institutional Accredited Investor to
                  whom such Restricted Certificated Security is being
                  transferred in substantially the form set forth in Exhibit
                  B-2, and, if the Company or such Security Registrar so
                  requests, a customary opinion of counsel, certificates and
                  other information reasonably acceptable to them as to the
                  compliance with the restrictions set forth in the legend
                  described in Section 102(f)(1); or

                           (D) if such Restricted Certificated Security is being
                  transferred (i) pursuant to an exemption from the registration
                  requirements of the Securities Act in accordance with Rule 144
                  or (ii) pursuant to an exemption from the registration
                  requirements of the Securities Act (other than pursuant to
                  Rule 144A or Rule 144) and as a result of which, in the case
                  of a Security transferred pursuant to this clause (ii), such
                  Security shall cease to be a "restricted security" within the
                  meaning of Rule 144, a certification to that effect from the
                  Holder (in substantially the form set forth in the Transfer
                  Certificate) and, if the Company or such Security Registrar so
                  requests, a customary opinion of counsel, certificates and
                  other information reasonably acceptable to the Company and
                  such Security Registrar to the effect that such transfer is in
                  compliance with the Securities Act.

                  (d) Transfer of a Beneficial Interest in a Restricted Global
Security for a Beneficial Interest in an Unrestricted Global Security. Any
person having a beneficial interest in

                                       6
<PAGE>

a Restricted Global Security may upon request, subject to the Applicable
Procedures, transfer such beneficial interest to a person who is required or
permitted to take delivery thereof in the form of an Unrestricted Global
Security. Upon receipt by the Trustee of written instructions or such other form
of instructions as is customary for the Depositary, from the Depositary or its
nominee on behalf of any person having a beneficial interest in a Restricted
Global Security and the following additional information and documents in such
form as is customary for the Depositary from the Depositary or its nominee on
behalf of the person having such beneficial interest in the Restricted Global
Security (all of which may be submitted by facsimile or electronically):

                      (1) if such beneficial interest is being transferred
           pursuant to an effective registration statement under the Securities
           Act, a certification to that effect from the transferor (in
           substantially the form set forth in the Transfer Certificate); or

                      (2) if such beneficial interest is being transferred (i)
           pursuant to an exemption from the registration requirements of the
           Securities Act in accordance with Rule 144 or (ii) pursuant to an
           exemption from the registration requirements of the Securities Act
           (other than pursuant to Rule 144A or Rule 144) and as a result of
           which, in the case of a Security transferred pursuant to this clause
           (ii), such Security shall cease to be a "restricted security" within
           the meaning of Rule 144, a certification to that effect from the
           transferor (in substantially the form set forth in the Transfer
           Certificate) and, if the Company or the Trustee so requests, a
           customary opinion of counsel, certificates and other information
           reasonably acceptable to the Company and the Trustee to the effect
           that such transfer is in compliance with the Securities Act,

the Trustee, as a Security Registrar and Securities Custodian, shall reduce or
cause to be reduced the aggregate principal amount of the Restricted Global
Security by the appropriate principal amount and shall increase or cause to be
increased the aggregate principal amount of the Unrestricted Global Security by
a like principal amount. Such transfer shall otherwise be effected in accordance
with the Applicable Procedures. If no Unrestricted Global Security is then
outstanding, the Company shall execute and the Trustee shall, upon receipt of a
Company Order (which the Company agrees to deliver promptly), authenticate and
deliver an Unrestricted Global Security.

                  (e) Transfers of Certificated Securities for Beneficial
Interest in Global Securities. If Certificated Securities are presented by a
Holder to a Security Registrar with a request:

                      (1) to register the transfer of such Certificated
           Securities to a person who will take delivery thereof in the form of
           a beneficial interest in a Global Security, which request shall
           specify whether such Global Security will be a Restricted Global
           Security or an Unrestricted Global Security; or

                      (2) to exchange such Certificated Securities for an equal
           principal amount of beneficial interests in a Global Security, which
           beneficial interests will be

                                       7
<PAGE>

           owned by the Holder transferring such Certificated Securities
           (provided that in the case of such an exchange, Restricted
           Certificated Securities may be exchanged only for Restricted Global
           Securities and Unrestricted Certificated Securities may be exchanged
           only for Unrestricted Global Securities),

the Security Registrar shall register the transfer or make the exchange as
requested by canceling such Certificated Security and causing, or directing the
Securities Custodian to cause, the aggregate principal amount of the applicable
Global Security to be increased accordingly and, if no such Global Security is
then outstanding, the Company shall issue and the Trustee shall authenticate and
deliver a new Global Security; provided, however, that the Certificated
Securities presented or surrendered for registration of transfer or exchange:

                      (3) shall be duly endorsed or accompanied by a written
           instrument of transfer in accordance with the fifth paragraph of
           Section 305 of the Indenture;

                      (4) in the case of a Restricted Certificated Security to
           be transferred for a beneficial interest in an Unrestricted Global
           Security, such request shall be accompanied by the following
           additional information and documents, as applicable:

                           (A) if such Restricted Certificated Security is being
                  transferred pursuant to an effective registration statement
                  under the Securities Act, a certification to that effect from
                  such Holder (in substantially the form set forth in the
                  Transfer Certificate); or

                           (B) if such Restricted Certificated Security is being
                  transferred pursuant to (i) an exemption from the registration
                  requirements of the Securities Act in accordance with Rule 144
                  or (ii) pursuant to an exemption from the registration
                  requirements of the Securities Act (other than pursuant to
                  Rule 144A or Rule 144) and as a result of which, in the case
                  of a Security transferred pursuant to this clause (ii), such
                  Security shall cease to be a "restricted security" within the
                  meaning of Rule 144, a certification to that effect from such
                  Holder (in substantially the form set forth in the Transfer
                  Certificate), and, if the Company or the Security Registrar so
                  requests, a customary opinion of counsel, certificates and
                  other information reasonably acceptable to the Company and the
                  Trustee to the effect that such transfer is in compliance with
                  the Securities Act;

                      (5) in the case of a Restricted Certificated Security to
           be transferred or exchanged for a beneficial interest in a Restricted
           Global Security, such request shall be accompanied by a certification
           from such Holder (in substantially the form set forth in the Transfer
           Certificate) to the effect that such Restricted Certificated Security
           is being transferred to a person the Holder reasonably believes is a
           QIB (which, in the case of an exchange, shall be such Holder) in
           accordance with Rule 144A; and

                      (6) in the case of an Unrestricted Certificated Security
           to be transferred or exchanged for a beneficial interest in an
           Unrestricted Global Security, such request need not be accompanied by
           any additional information or documents.

                                       8
<PAGE>

                  (f) Legends.

                      (1) Except as permitted by the following paragraphs (2)
           and (3), each Global Security and Certificated Security (and all
           Securities issued in exchange therefor or upon registration of
           transfer or replacement thereof) shall bear a legend in substantially
           the form called for by footnote 2 to Annex A hereto (each a "Transfer
           Restricted Security" for so long as such Security is required by this
           Indenture to bear such legend). Each Transfer Restricted Security
           shall have attached thereto a Transfer Certificate in substantially
           the form set forth in Exhibit B-1 hereto.

                      (2) Upon any sale or transfer of a Transfer Restricted
           Security (x) pursuant to Rule 144, (y) pursuant to an effective
           registration statement under the Securities Act or (z) pursuant to
           any other available exemption (other than Rule 144A) from the
           registration requirements of the Securities Act and as a result of
           which, in the case of a Security transferred pursuant to this clause
           (z), such Security shall cease to be a "restricted security" within
           the meaning of Rule 144:

                           (A) in the case of any Restricted Certificated
                  Security, any Security Registrar shall permit the Holder
                  thereof to exchange such Restricted Certificated Security for
                  an Unrestricted Certificated Security, or (under the
                  circumstances described in Section 102(e) hereof) to transfer
                  such Restricted Certificated Security to a transferee who
                  shall take such Security in the form of a beneficial interest
                  in an Unrestricted Global Security, and in each case shall
                  rescind any restriction on the transfer of such Security;
                  provided, however, that the Holder of such Restricted
                  Certificated Security shall, in connection with such exchange
                  or transfer, comply with the other applicable provisions of
                  this Section 102; and

                           (B) in the case of any beneficial interest in a
                  Restricted Global Security, the Trustee shall permit the
                  beneficial owner thereof to transfer such beneficial interest
                  to a transferee who shall take such interest in the form of a
                  beneficial interest in an Unrestricted Global Security and
                  shall rescind any restriction on transfer of such beneficial
                  interest; provided, however, that such Unrestricted Global
                  Security shall continue to be subject to the provisions of
                  Section 102(a)(2) hereof, and provided further, however, that
                  the owner of such beneficial interest shall, in connection
                  with such transfer, comply with the other applicable
                  provisions of this Section 102.

                      (3) Upon the exchange, registration of transfer or
           replacement of Securities not bearing the legend described in
           paragraph (1) above, the Company shall execute, the Trustee shall
           authenticate and deliver Securities that do not bear such legend and
           which do not have a Transfer Certificate attached thereto.

                  (g) Transfers to the Company. Nothing in this Indenture or in
the Securities shall prohibit the sale or other transfer of any Securities
(including beneficial interests in Global

                                       9
<PAGE>

Securities) to the Company or any of its Subsidiaries, which Securities shall
thereupon be canceled in accordance Section 309 of the Indenture.

Section 103 Amount.

         The Trustee shall authenticate and deliver 2014 Notes for original
issue in an aggregate principal amount of up to $250,000,000 upon a Company
Order for the authentication and delivery of 2014 Notes, without any further
action by the Company. The aggregate principal amount of 2014 Notes that may be
authenticated and delivered under the Indenture may not exceed the amount set
forth in the foregoing sentence, except for 2014 Notes authenticated and
delivered upon registration of transfer of, or in exchange for, or in lieu of,
other 2014 Notes pursuant to Section 102 of this Fourth Supplemental Indenture
or Section 204, 304, 305, 306, 906 or 1107 of the Indenture.

Section 104 Regular Interest.

         The principal of the 2014 Notes shall bear interest at the rate of
5.15% per annum from August 27, 2004 or from the most recent Interest Payment
Date to which interest has been paid or duly provided for, payable semiannually
in arrears on March 1 and September 1 of each year, commencing March 1, 2005, to
the Persons in whose names the 2014 Notes are registered at the close of
business on the February 15 or August 15 (whether or not a Business Day), as the
case may be, next preceding such Interest Payment Date. Interest on the 2014
Notes will be computed on the basis of a 360-day year comprised of twelve 30-day
months.

Section 105 Liquidated Damages.

         Liquidated Damages with respect to the 2014 Notes shall be payable in
accordance with the provisions and in the amounts set forth in the Registration
Rights Agreement.

Section 106 Denominations.

         The 2014 Notes shall be in fully registered form without coupons in
denominations of $1,000 of principal amount or any integral multiple thereof.

Section 107 Place of Payment.

         The Place of Payment for the 2014 Notes and the place or places where
the 2014 Notes may be surrendered for registration of transfer, exchange or
redemption and where notices may be given to the Company in respect of the 2014
Notes is at the office of the Trustee in New York, New York and at the agency of
the Trustee maintained for that purpose at the office of the Trustee; provided,
however, that payment of interest may be made at the option of the Company by
check mailed to the address of the Person entitled thereto as such address shall
appear in the Security Register (as defined in the Indenture).

                                       10
<PAGE>

Section 108 Redemption.

                  (a) There shall be no sinking fund for the retirement of the
2014 Notes.

                  (b) The Company, at its option, may redeem the 2014 Notes in
accordance with the provisions and at the Redemption Price set forth under the
captions "Optional Redemption" and "Notice of Redemption" in the 2014 Notes and
in accordance with the provisions of the Indenture, including, without
limitation, Article Eleven.

Section 109 Stated Maturity.

         The date on which the principal of the 2014 Notes is due and payable,
unless accelerated, redeemed or required to be repurchased pursuant to the
Indenture, shall be September 1, 2014.

Section 110 Discharge of Liability on 2014 Notes.

         The 2014 Notes may be discharged by the Company in accordance with the
provisions of Article Four of the Indenture, as amended by Section 205 hereof.

Section 111 Other Terms of 2014 Notes.

         Without limiting the foregoing provisions of this Article One, the
terms of the 2014 Notes shall be as set forth in the form of the 2014 Notes set
forth in Annex A hereto and as provided in the Indenture.

                                   ARTICLE TWO

                           AMENDMENTS TO THE INDENTURE

Section 201 Amendments Applicable Only to 2014 Notes.

         The amendments contained herein shall apply to the 2014 Notes only and
not to any other series of Security issued under the Indenture and any covenants
provided herein are expressly being included solely for the benefit of the 2014
Notes and not for the benefit of any other series of Security issued under the
Indenture. These amendments shall be effective for so long as there remain any
2014 Notes Outstanding.

Section 202 Definitions.

         Section 101 of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by inserting or restating, as
the case may be, in their appropriate alphabetical position, the following
definitions:

         "Agent Members" has the meaning specified in Section 101.

         "Applicable Procedures" means, with respect to any transfer or exchange
of beneficial ownership interests in a Global Security, the rules and procedures
that are applicable to such

                                       11
<PAGE>

transfer or exchange of the Depositary and its direct or indirect participants,
including, if applicable, those of Euroclear Bank S.A./N.V. (as operator of the
Euroclear system) and Clearstream Banking Luxembourg, which may change from time
to time.

         "Capital Stock" or "capital stock" of any Person means any and all
shares, interests, partnership interests, participations, rights or other
equivalents (however designated) of equity interests (however designated) issued
by that Person.

         "Certificated Security" means a Security that is in substantially the
form attached hereto as Annex A and that does not include the information or the
schedule called for by footnotes 1, 3 and 4 thereof.

         "Comparable Treasury Issue" means the U.S. Treasury security selected
by the Quotation Agent as having a maturity comparable to the Remaining Life
that would be utilized, at the time of selection and in accordance with
customary financial practice, in pricing new issues of corporate debt securities
of comparable maturity with the Remaining Life as of the applicable redemption
date.

         "Comparable Treasury Price" means, with respect to any redemption date,
the average of two Reference Treasury Dealer Quotations for such redemption
date.

         "Consolidated Net Tangible Assets" means the total amount of assets
(less applicable reserves and other properly deductible items) after deducting
(1) all current liabilities (excluding the amount of those which are by their
terms extendable or renewable at the option of the obligor to a date more than
12 months after the date as of which the amount is being determined) and (2) all
goodwill, tradenames, trademarks, patents, unamortized debt discount and expense
and other like intangible assets, all as set forth on the most recent balance
sheet of the Company and its consolidated subsidiaries and determined in
accordance with generally accepted accounting principles.

         "Consolidated Net Worth" means, at any time, the Net Worth of the
Company and its Subsidiaries on a consolidated basis determined in accordance
with GAAP.

         "Corporate Trust Office" means the principal office of the Trustee in
New York, New York, at which at any particular time its corporate trust business
shall be principally administered, which office at the date hereof is located at
Institutional Trust Services, 4 New York Plaza, New York, New York 10004, except
that with respect to the presentation of Securities for payment or for
registration of transfer and exchange, such term shall mean the office or the
agency of the Trustee in said city at which at any particular time its corporate
agency business shall be conducted, which office at the date hereof is located
at 4 New York Plaza, Ground Level, GIS Unit Trust Window, New York, New York
10004.

         "Depositary" has the meaning specified in Section 101(a).

         "DTC" has the meaning specified in Section 101(a).

                                       12
<PAGE>

         "Exchange Act" means the Securities Exchange Act of 1934, as amended,
or any successor statute.

         "Funded Debt" means indebtedness of the Company or a Subsidiary owning
Restricted Property maturing by its terms more than one year after its creation
and indebtedness classified as long-term debt under generally accepted
accounting principles, and in each case ranking at least pari passu with the
Securities.

         "GAAP" means generally accepted accounting principles as in effect on
the date of determination in the United States.

         "Global Security" means a permanent Global Security that is in
substantially the form attached hereto as Annex A and that includes the
information and schedule called for by footnotes 1, 3 and 4 thereof and which is
deposited with the Depositary or the Securities Custodian and registered in the
name of the Depositary or its nominee.

         "Indenture" has the meaning specified in the recitals.

         "Institutional Accredited Investors" has the meaning specified in
Section 101(b).

         "Issue Date" of any 2014 Notes means the date on which the 2014 Notes
was originally issued or deemed issued as set forth on the face of the 2014
Notes.

         "Lien" means any mortgage, pledge, lien, encumbrance, charge or
security interest.

         "Liquidated Damages" shall have the meaning set forth in the
Registration Rights Agreement.

         "Net Worth" means, at any time with respect to the Company or a
Subsidiary thereof, the net worth of the Company or such Subsidiary, as the case
may be, determined in accordance with GAAP.

         "QIB" has the meaning specified in Section 101(a).

         "Quotation Agent" means the Reference Treasury Dealer appointed by the
Company.

         "Reference Treasury Dealer" means Goldman, Sachs & Co. and its
successors; provided, however, that if the foregoing ceases to be a primary U.S.
Government securities dealer in New York, New York, the Company shall substitute
therefor another primary U.S. Government securities dealer.

         "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any redemption date, the average, as determined by
the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by such Reference Treasury Dealer at 5:00 p.m., New York,
New York time, on the third Business Day preceding such redemption date.

                                       13
<PAGE>

         "Registration Rights Agreement" means the Exchange and Registration
Rights Agreement, dated as of August 27, 2004, between the Company and Goldman,
Sachs & Co.

         "Regulation S" means Regulation S under the Securities Act or any
successor to such Rule.

         "Restricted Certificated Security" means a Certificated Security which
is a Transfer Restricted Security.

         "Restricted Global Security" means a Global Security that is a Transfer
Restricted Security.

         "Restricted Period" means the period through and including the 40th day
following the later of the commencement of the offering and the Issue Date of
the 2014 Notes.

         "Restricted Property" means (1) any drilling rig or drillship which is
leased by the Company or any Subsidiary as a lessee, or greater than a 50%
interest in which is owned by the Company or any Subsidiary, and which is used
for drilling offshore oil and gas wells, which, in the opinion of the Board of
Directors, is of material importance to the business of the Company and its
Subsidiaries taken as a whole, but no such drilling rig or drillship, or portion
thereof, shall be deemed of material importance if its net book value is less
than 2% of Consolidated Net Tangible Assets, or (2) any shares of capital stock
or indebtedness of any Subsidiary owning any such drilling rig or drillship.

         "Rule 144" means Rule 144 under the Securities Act or any successor to
such Rule.

         "Rule 144A" means Rule 144A under the Securities Act or any successor
to such Rule.

         "Sale and Leaseback Transaction" means any arrangement with any Person
pursuant to which the Company or any Subsidiary leases any Restricted Property
that has been or is to be sold or transferred by the Company or the Subsidiary
to such Person, other than (1) leases for a term, including renewals at the
option of the lessee, of not more than five years, (2) leases between the
Company and a Subsidiary or between Subsidiaries, (3) leases of a Restricted
Property executed by the time of, or within 12 months after the latest of, the
acquisition, the completion of construction or improvement, or the commencement
of commercial operation of the Restricted Property, and (4) arrangements
pursuant to any provision of law with an effect similar to the former Section
168(f)(8) of the Internal Revenue Code of 1954.

         "Securities" means any securities authenticated and delivered under the
Indenture, as the same may be amended or supplemented, including 2014 Notes.

         "Securities Act" means the Securities Act of 1933, as amended, or any
successor statute.

         "Securities Custodian" means the Trustee, as custodian with respect to
the Securities in global form, or any successor thereto.

                                       14
<PAGE>

         "Significant Subsidiary" means any Subsidiary, the Net Worth of which
represents more than 10% of the Consolidated Net Worth of the Company and its
Subsidiaries.

         "Transfer Certificate"' has the meaning specified in Section 102(b)(1).

         "Transfer Restricted Securities" has the meaning specified in Section
102(f)(1).

         "Treasury Rate" means, with respect to any redemption date, the annual
rate equal to the semiannual yield to maturity of the Comparable Treasury Issue,
calculated on the third Business Day preceding such redemption date using a
price for the Comparable Treasury Issue (expressed as a percentage of its
principal amount) equal to the Comparable Treasury Price for such redemption
date. The Company may at any time, and from time to time, purchase the 2014
Notes at any price or prices in the open market or otherwise.

         "2014 Notes" has the meaning specified in the recitals.

         "Unrestricted Certificated Security" means a Certificated Security
which is not a Transfer Restricted Security.

         "Unrestricted Global Security" means a Global Security which is not a
Transfer Restricted Security.

         "Value" means, with respect to a Sale and Leaseback Transaction, an
amount equal to the present value of the lease payments with respect to the term
of the lease remaining on the date as of which the amount is being determined,
without regard to any renewal or extension options contained in the lease
(including the effective interest rate on any original issue discount
Securities), which are outstanding on the effective date of such Sale and
Leaseback Transaction and which have the benefit of Section 1010.

Section 203 Registration, Registration of Transfer and Exchange.

         The Indenture is hereby amended, subject to Section 201 hereof and with
respect to the 2014 Notes only, by replacing the seventh paragraph of Section
305 with the following paragraph:

                  The Company shall not be required (i) to issue, register the
         transfer of or exchange the Securities of any series during a period
         beginning at the opening of business 15 days before the day of the
         mailing of a notice of redemption of Securities of that series selected
         for redemption and ending at the close of business on the day of such
         mailing or (ii) to register the transfer of or exchange any 2014 Notes
         so selected for redemption in whole or in part, except the unredeemed
         portion of any 2014 Notes being redeemed in part.

                                       15
<PAGE>

Section 204 Mutilated, Destroyed, Lost and Stolen Securities.

         The Indenture is hereby amended, subject to Section 201 hereof and with
respect to the 2014 Notes only, by replacing the second paragraph of Section 306
with the following paragraph:

                  In case any such mutilated, destroyed, lost or stolen Security
         has or is about to become due and payable, or is about to be redeemed
         by the Company pursuant to Article Eleven, the Company in its
         discretion may, instead of issuing a new Security, pay such Security.

Section 205 Amendment of Article Four of the Indenture.

         Article Four of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by deleting Sections 401, 402
and 403 and replacing those sections with the following:

         Section 401 Discharge of Liability on Securities.

                  When (i) the Company delivers to the Trustee or any Paying
         Agent all Outstanding 2014 Notes (other than 2014 Notes replaced
         pursuant to Section 306) for cancellation or (ii) all Outstanding 2014
         Notes have become due and payable and the Company deposits with the
         Trustee or any Paying Agent cash sufficient to pay all amounts due and
         owing on all Outstanding 2014 Notes (other than 2014 Notes replaced
         pursuant to Section 306), and if the Company pays all other sums
         payable hereunder by the Company, then this Indenture shall, subject to
         Section 607, cease to be of further effect, except for the
         indemnification of the Trustee, which shall survive. The Trustee shall
         join in the execution of a document prepared by the Company
         acknowledging satisfaction and discharge of this Indenture on demand of
         the Company accompanied by an Officers' Certificate and Opinion of
         Counsel and at the cost and expense of the Company.

         Section 402 Repayment to the Company.

                  The Trustee and the Paying Agent shall return to the Company
         upon written request any money or securities held by them for the
         payment of any amount with respect to the 2014 Notes that remains
         unclaimed for two years, subject to applicable unclaimed property law.
         After return to the Company, Holders entitled to the money or
         securities must look to the Company for payment as general creditors
         unless an applicable abandoned property law designates another person
         and the Trustee and the Paying Agent shall have no further liability to
         the Holders of 2014 Notes with respect to such money or securities for
         that period commencing after the return thereof.

                                       16
<PAGE>

Section 206 Amendment to Section 501 of the Indenture.

         Section 501 of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by deleting subsections (1),
(2), (3), (4), (5) and (6) thereof, and inserting the following as new
subsections (1), (2), (3), (4), (5) and (6) thereof:

                  (1) default in the payment of any interest upon any 2014 Notes
         when it becomes due and payable or in the payment of any Liquidated
         Damages pursuant to the Registration Rights Agreement, and continuance
         of such default for a period of 30 days; or

                  (2) default in the payment of the principal amount at its
         Maturity on the 2014 Notes or the Redemption Price by the Company; or

                  (3) a default under any bonds, debentures, notes or other
         evidences of indebtedness for money borrowed by the Company or a
         Subsidiary or under any mortgages, indentures or instruments under
         which there may be issued or by which there may be secured or evidenced
         any indebtedness for money borrowed by the Company or a Subsidiary,
         whether such indebtedness now exists or shall hereafter be created,
         which indebtedness, individually or in the aggregate, is in excess of
         $25.0 million principal amount (excluding any such indebtedness of any
         Subsidiary other than a Significant Subsidiary, all the indebtedness of
         which Subsidiary is nonrecourse to the Company or any other
         Subsidiary), which default shall constitute a failure to pay any
         portion of the principal of such indebtedness when due and payable
         after the expiration of any applicable grace or cure period with
         respect thereto or shall have resulted in such indebtedness becoming or
         being declared due and payable prior to the date on which it would
         otherwise have become due and payable, without such indebtedness having
         been discharged, or such acceleration having been rescinded or
         annulled, within a period of 10 days after there shall have been given,
         by registered or certified mail, to the Company by the Trustee or to
         the Company and the Trustee by the Holders of at least 25% in principal
         amount of the Outstanding 2014 Notes a written notice specifying such
         default and requiring the Company to cause such indebtedness to be
         discharged or cause such acceleration to be rescinded or annulled and
         stating that such notice is a "Notice of Default" hereunder; or

                  (4) default by the Company in the performance, or breach, of
         any covenant or warranty of the Company in this Indenture (other than a
         covenant or warranty a default in whose performance or whose breach is
         elsewhere in this Section 501 specifically dealt with), and continuance
         of such default or breach for a period of 60 days after there has been
         given, by registered or certified mail, to the Company by the Trustee
         or to the Company and the Trustee by the Holders of at least 25% in
         principal amount of the Outstanding 2014 Notes a written notice
         specifying such default or breach and requiring it to be remedied and
         stating that such notice is a "Notice of Default" hereunder; or

                  (5) the entry by a court having jurisdiction in the premises
         of (A) a decree or order for relief in respect of the Company or a
         Significant Subsidiary in an

                                       17
<PAGE>

         involuntary case or proceeding under any applicable Federal or State
         bankruptcy, insolvency, reorganization or other similar law or (B) a
         decree or order adjudging the Company or a Significant Subsidiary a
         bankrupt or insolvent, or approving as properly filed a petition
         seeking reorganization, arrangement, adjustment or composition of or in
         respect of the Company or a Significant Subsidiary under any applicable
         Federal or State law, or appointing a custodian, receiver, liquidator,
         assignee, trustee, sequestrator or other similar official of the
         Company or a Significant Subsidiary or of any substantial part of their
         respective properties, or ordering the winding up or liquidation of the
         affairs of the Company or a Significant Subsidiary, and the continuance
         of any such decree or order for relief or any such other decree or
         order unstayed and in effect for a period of 60 consecutive days; or

                  (6) the commencement by the Company or a Significant
         Subsidiary of a voluntary case or proceeding under any applicable
         Federal or State bankruptcy, insolvency, reorganization or other
         similar law or of any other case or proceeding to be adjudicated a
         bankrupt or insolvent, or the consent by either the Company or a
         Significant Subsidiary to the entry of a decree or order for relief in
         respect of the Company or a Significant Subsidiary in an involuntary
         case or proceeding under any applicable Federal or State bankruptcy,
         insolvency, reorganization or other similar law or to the commencement
         of any bankruptcy or insolvency case or proceeding against either the
         Company or a Significant Subsidiary, or the filing by either the
         Company or a Significant Subsidiary of a petition or answer or consent
         seeking reorganization or relief under any applicable Federal or State
         law, or the consent by either the Company or a Significant Subsidiary
         to the filing of such petition or to the appointment of or taking
         possession by a custodian, receiver, liquidator, assignee, trustee,
         sequestrator or other similar official of the Company or a Significant
         Subsidiary or of any substantial part of their respective properties,
         or the making by either the Company or a Significant Subsidiary of an
         assignment for the benefit of creditors, or the admission by either the
         Company or a Significant Subsidiary in writing of an inability to pay
         the debts of either the Company or a Significant Subsidiary generally
         as they become due, or the taking of corporate action by the Company or
         a Significant Subsidiary in furtherance of any such action.

Section 207 Reports by Company.

         Section 704 of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by adding the following
paragraph thereto:

                  (4) If at any time while any of the Securities are "restricted
         securities" within the meaning of Rule 144, the Company is no longer
         subject to the reporting requirements of Section 13 or 15(d) of the
         Exchange Act, the Company will prepare and will furnish to any Holder,
         any beneficial owner of Securities and any prospective purchaser of
         Securities designated by a Holder or a beneficial owner of Securities,
         promptly upon request, the information required pursuant to

                                       18
<PAGE>

         Rule 144A(d)(4) (or any successor thereto) under the Securities Act in
         connection with the offer, sale or transfer of Securities.

Section 208 Amendment to Section 801 of the Indenture.

         Section 801 of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by deleting subsection (1)
thereof, and inserting the following as new subsection (1) thereof:

                  (1) the Person formed by such consolidation or into which the
         Company is merged or the Person which acquires by conveyance or
         transfer the properties and assets of the Company substantially as an
         entirety shall expressly assume, by an indenture supplemental hereto,
         executed and delivered to the Trustee, in form satisfactory to the
         Trustee, the due and punctual payment of the principal of (and premium,
         if any) and interest on all the Securities (including Liquidated
         Damages, if any) on all the Securities and the performance of every
         covenant of this Indenture on the part of the Company to be performed
         or observed;

Section 209 Amendment to Article Ten of the Indenture.

         Article Ten of the Indenture is hereby amended, subject to Section 201
hereof and with respect to the 2014 Notes only, by adding the following sections
thereto:

         SECTION 1006 Maintenance of Properties.

                  The Company will cause all properties used or useful in the
         conduct of its business or the business of any Subsidiary to be
         maintained and kept in good condition, repair and working order, normal
         wear and tear excepted, and supplied with all necessary equipment and
         will cause to be made all necessary repairs, renewals, replacements,
         betterments and improvements thereof, all as in the judgment of the
         Company may be necessary so that the business carried on in connection
         therewith may be properly and advantageously conducted at all times;
         provided, however, that nothing in this Section 1006 shall prevent the
         Company from discontinuing the operation or maintenance of any of such
         properties, or disposing of any of them, if such discontinuance or
         disposition is, in the judgment of the Company, desirable in the
         conduct of its business or the business of any Subsidiary.

         SECTION 1007 Payment of Taxes and Other Claims.

                  The Company will pay or discharge or cause to be paid or
         discharged, before the same shall become delinquent, (1) all taxes,
         assessments and governmental charges levied or imposed upon the Company
         or any Subsidiary or upon the income, profits or property of the
         Company or any Subsidiary, and (2) all lawful claims for labor,
         materials and supplies which, if unpaid, might by law become a material
         Lien upon the property of the Company or any Subsidiary;

                                       19
<PAGE>

         provided, however, that the Company shall not be required to pay or
         discharge or cause to be paid or discharged any such tax, assessment,
         charge or claim whose amount, applicability or validity is being
         contested in good faith by appropriate proceedings.

         SECTION 1008 Waiver of Certain Covenants.

                  The Company may omit in any particular instance to comply with
         any covenant or condition set forth in Sections 1005 to 1010,
         inclusive, if before the time for such compliance the Holders of at
         least a majority in principal amount of the Outstanding 2014 Notes
         shall, by Act of such Holders, either waive such compliance in such
         instance or generally waive compliance with such covenant or condition,
         but no such waiver shall extend to or affect such covenant or condition
         except to the extent so expressly waived, and, until such waiver shall
         become effective, the obligations of the Company and the duties of the
         Trustee in respect of any such covenant or condition shall remain in
         full force and effect.

         SECTION 1009 Limitation on Liens.

                  The Company shall not create, assume or suffer to exist any
         Lien on any Restricted Property to secure any debt of the Company, any
         Subsidiary or any other Person, or permit any Subsidiary so to do,
         without making effective provision whereby the 2014 Notes then
         outstanding and having the benefit of this Section shall be secured by
         a Lien equally and ratably with such debt for so long as such debt
         shall be so secured, except that the foregoing shall not prevent the
         Company or any Subsidiary from creating, assuming or suffering to exist
         Liens of the following character:

                  (1) any Lien existing on the Issue Date of the 2014 Notes;

                  (2) any Lien existing on Restricted Property owned or leased
         by a corporation at the time it becomes a Subsidiary;

                  (3) any Lien existing on Restricted Property at the time of
         the acquisition thereof by the Company or a Subsidiary;

                  (4) any Lien to secure any debt incurred prior to, at the time
         of, or within 12 months after the acquisition of Restricted Property
         for the purpose of financing all or any part of the purchase price
         thereof and any Lien to the extent that it secures debt which is in
         excess of such purchase price and for the payment of which recourse may
         be had only against such Restricted Property;

                  (5) any Lien to secure any debt incurred prior to, at the time
         of, or within 12 months after the completion of the construction and
         commencement of commercial operation, alteration, repair or improvement
         of Restricted Property for the purpose of financing all or any part of
         the cost thereof and any Lien to the

                                       20
<PAGE>

         extent that it secures debt which is in excess of such cost and for the
         payment of which recourse may be had only against such Restricted
         Property;

                  (6) any Lien securing debt of a Subsidiary owing to the
         Company or to another Subsidiary;

                  (7) any Lien in favor of the United States of America or any
         State thereof or any other country, or any agency, instrumentality of
         political subdivision try of any of the foregoing, to secure partial,
         progress, advance or other payments or performance pursuant to the
         provisions of any contract or statute, or any Liens securing industrial
         development, pollution control, or similar revenue bonds;

                  (8) Liens imposed by law, such as mechanics', workmen's,
         repairmen's, materialmen's, carriers', warehousemen's, vendors' or
         other similar Liens arising in the ordinary course of business, or
         governmental (federal, state or municipal) Liens arising out of
         contracts for the sale of products or services by the Company or any
         Subsidiary, or deposits or pledges to obtain the release of any of the
         foregoing;

                  (9) pledges or deposits under workmen's compensation laws or
         similar legislation and Liens of judgments thereunder which are not
         currently dischargeable, or good faith deposits in connection with
         bids, tenders, contracts (other than for the payment of money) or
         leases to which the Company or any Subsidiary is a party, or deposits
         to secure public or statutory obligations of the Company or any
         Subsidiary, or deposits in connection with obtaining or maintaining
         self-insurance or to obtain the benefits of any law, regulation or
         arrangement pertaining to unemployment insurance, old age pensions,
         social security or similar matters, or deposits of cash or obligations
         of the United States of America to secure surety, appeal or customs
         bonds to which the Company or any Subsidiary is a party, or deposits in
         litigation or other proceedings such as, but not limited to,
         interpleader proceedings;

                  (10) Liens created by or resulting from any litigation or
         other proceeding which is being contested in good faith by appropriate
         proceedings, including Liens arising out of judgments or awards against
         the Company or any Subsidiary with respect to which the Company or such
         Subsidiary is in good faith prosecuting an appeal or proceedings for
         review; or Liens incurred by the Company or any Subsidiary for the
         purpose of obtaining a stay or discharge in the course of any
         litigation or other proceeding to which the Company or such Subsidiary
         is a party;

                  (11) Liens for taxes or assessments or governmental charges or
         levies not yet due or delinquent, or which can thereafter be paid
         without penalty, or which are being contested in good faith by
         appropriate proceedings;

                                       21
<PAGE>

                  (12) any extension, renewal or replacement (or successive
         extensions, renewals or replacements) in whole or in part of any Lien
         referred to in clauses (1) through (11) above, so long as the principal
         amount of the debt secured thereby does not exceed the principal amount
         of debt so secured at the time of the extension, renewal or replacement
         (except that, where an additional principal amount of debt is incurred
         to provide funds for the completion of a specific project, the
         additional principal amount, and any related financing costs, may be
         secured by the Lien as well) and the Lien is limited to the same
         property subject to the Lien so extended, renewed or replaced (plus
         improvements on the property); and

                  (13) any Lien not permitted by clauses (1) through (12) above
         securing debt that, together with the aggregate outstanding principal
         amount of all other debt of the Company and its Subsidiaries secured by
         Liens which would otherwise be prohibited by the foregoing restrictions
         and the aggregate Value of existing Sale and Leaseback Transactions
         which would be subject to the restrictions of Section 1010 but for this
         clause (13), does not at any time exceed 10% of Consolidated Net
         Tangible Assets.

         SECTION 1010 Limitation on Sale And Leasebacks.

              The Company shall not enter into any Sale and Leaseback
         Transaction covering any Restricted Property, nor permit any Subsidiary
         so to do, unless either:

              (1) the Company or such Subsidiary would be entitled to incur
         debt, in a principal amount at least equal to the Value of such Sale
         and Leaseback Transaction, which is secured by Liens on the property to
         be leased (without equally and ratably securing the Outstanding 2014
         Notes) because such Liens would be of such character that no violation
         of the provisions of Section 1009 would result, or

              (2) the Company during the six months immediately following
         the effective date of such Sale and Leaseback Transaction causes to be
         applied to (A) the acquisition of Restricted Property or (B) the
         voluntary retirement of Funded Debt (whether by redemption, defeasance,
         repurchase, or otherwise) an amount equal to the Value of such Sale and
         Leaseback Transaction.

                                  ARTICLE THREE

                            MISCELLANEOUS PROVISIONS

Section 301 Integral Part.

         This Fourth Supplemental Indenture constitutes an integral part of the
Indenture with respect to the 2014 Notes only.

                                       22
<PAGE>

Section 302 General Definitions.

         For all purposes of this Fourth Supplemental Indenture:

         (a) capitalized terms used herein without definition shall have the
meanings specified in the Indenture; and

         (b) the terms "herein", "hereof', "hereunder" and other words of
similar import refer to this Fourth Supplemental Indenture.

Section 303 Adoption, Ratification and Confirmation.

         The Indenture, as supplemented and amended by this Fourth Supplemental
Indenture, is in all respects hereby adopted, ratified and confirmed, and this
Fourth Supplemental Indenture shall be deemed part of the Indenture in the
manner and to the extent herein and therein provided. The provisions of this
Fourth Supplemental Indenture shall, subject to the terms hereof, supersede the
provisions of the Indenture to the extent the Indenture is inconsistent
herewith.

Section 304 Counterparts.

         This Fourth Supplemental Indenture may be executed in any number of
counterparts, each of which when so executed shall be deemed an original; and
all such counterparts shall together constitute but one and the same instrument.

Section 305 Governing Law.

         THIS FOURTH SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO THE
CONFLICTS OF LAW RULES OF SAID STATE.

Section 306 Conflict of Any Provision of Indenture with Trust Indenture Act of
1939.

         If and to the extent that any provision of this Fourth Supplemental
Indenture limits, qualifies or conflicts with a provision required under the
terms of the Trust Indenture Act of 1939, as amended, such Trust Indenture Act
provision shall control.

Section 307 Effect of Headings.

         The Article and Section headings herein are for convenience only and
shall not affect the construction hereof.

Section 308 Severability of Provisions.

         In case any provision in this Fourth Supplemental Indenture or in the
2014 Notes shall be invalid, illegal or unenforceable, the validity, legality
and enforceability of the remaining provisions shall not in any way be affected
or impaired thereby.

                                       23
<PAGE>

Section 309 Successors and Assigns.

         All covenants and agreements in this Fourth Supplemental Indenture by
the parties hereto shall bind their respective successors and assigns and inure
to the benefit of their respective successors and assigns, whether so expressed
or not.

Section 310 Benefit of Fourth Supplemental Indenture.

         Nothing in this Fourth Supplemental Indenture, express or implied,
shall give to any Person, other than the parties hereto, any Security Registrar,
any Paying Agent, and their successors hereunder, and the Holders of the 2014
Notes, any benefit or any legal or equitable right, remedy or claim under this
Fourth Supplemental Indenture.

Section 311 Acceptance by Trustee.

         The Trustee accepts the amendments to the Indenture effected by this
Fourth Supplemental Indenture and agrees to execute the trusts created by the
Indenture as hereby amended, but only upon the terms and conditions set forth in
this Fourth Supplemental Indenture and the Indenture. Without limiting the
generality of the foregoing, the Trustee assumes no responsibility for the
correctness of the recitals contained herein, which shall be taken as the
statements of the Company and except as provided in the Indenture the Trustee
shall not be responsible or accountable in any way whatsoever for or with
respect to the validity or execution or sufficiency of this Fourth Supplemental
Indenture and the Trustee makes no representation with respect thereto.

                                       24
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Fourth
Supplemental Indenture to be duly executed and their respective corporate seals
to be hereunto fixed and attested as of the day and year first written above.

                               DIAMOND OFFSHORE DRILLING, INC.

                               By: /s/ William C. Long
                                   ---------------------------------------------
                                   William C. Long
                                   Vice President, General Counsel and Secretary

                               JPMORGAN CHASE BANK, as Trustee

                               By: /s/ James D. Heaney
                                   ---------------------------------------------
                                   James D. Heaney
                                   Vice President

                                       25
<PAGE>

STATE OF TEXAS            }

COUNTY OF HARRIS          }

         On the 27th day of August, 2004, before me personally appeared William
C. Long, to me known, who, being by me duly sworn, did depose and say that he is
Vice President, General Counsel and Secretary of DIAMOND OFFSHORE DRILLING,
INC., one of the corporations described in and which executed the foregoing
instrument; that he knows the seal of said corporation; that the seal affixed to
said instrument is such corporate seal; that it was so affixed by authority of
the Board Directors of said corporation, and that he signed his name thereto by
like authority.

                                                  ------------------------------
                                                              Notary

STATE OF NEW YORK         }

COUNTY OF NEW YORK        }

         On the 27th day of August, 2004, before me personally appeared James D.
Heaney, to me known, who, being by me duly sworn, did depose and say that such
person is a Vice President of JPMORGAN CHASE BANK, one of the corporations
described in and which executed the foregoing instrument; that he knows the seal
of said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by authority of the Board Directors of said
corporation, and that such person signed his name thereto by like authority.

                                                  ------------------------------
                                                              Notary

                                       26
<PAGE>

                                                                         ANNEX A

                                 GLOBAL SECURITY

                           [FORM OF FACE OF SECURITY]

         [THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. THIS SECURITY IS EXCHANGEABLE FOR SECURITIES REGISTERED IN THE
NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED
CIRCUMSTANCES DESCRIBED IN THE INDENTURE AND, UNLESS AND UNTIL IT IS EXCHANGED
IN WHOLE OR IN PART FOR SECURITIES IN DEFINITIVE FORM, THIS SECURITY MAY NOT BE
TRANSFERRED EXCEPT AS A WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY
OR BY A NOMINEE OF THE DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE
DEPOSITARY OR BY THE DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR
A NOMINEE OF SUCH SUCCESSOR DEPOSITARY.

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN
WHOLE, BUT NOT IN PART, TO NOMINEES OF THE DEPOSITORY TRUST COMPANY, OR TO A
SUCCESSOR THEREOF OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS
GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
RESTRICTIONS SET FORTH IN ARTICLE ONE OF THE INDENTURE REFERRED TO ON THE
REVERSE HEREOF.](1)

         [THIS SECURITY (OR ITS PREDECESSOR) HAS NOT BEEN REGISTERED UNDER THE
UNITED STATES SECURITIES ACT OF 1933 (THE "SECURITIES ACT"), WAS ORIGINALLY
ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION

----------
(1) These paragraphs should be included only if the Security is a Global
    Security.

                                      A-1
<PAGE>

UNDER THE SECURITIES ACT, AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION
THEREFROM. EACH PURCHASER OF THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF
THIS SECURITY MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5
OF THE SECURITIES ACT PROVIDED BY RULE 144A OR REGULATION S THEREUNDER.

         THE HOLDER OF THIS SECURITY, BY ITS ACCEPTANCE HEREOF, AGREES THAT THIS
SECURITY MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT (A)
BY THE INITIAL INVESTOR (1) TO THE COMPANY OR ANY SUBSIDIARY THEREOF, (2) FOR SO
LONG AS THE SECURITIES ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A
PERSON IT REASONABLY BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN
RULE 144A UNDER THE SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE
ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHICH NOTICE IS GIVEN THAT THE
TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A IN A TRANSACTION MEETING THE
REQUIREMENTS OF RULE 144A, (3) IN AN OFFSHORE TRANSACTION COMPLYING WITH RULE
903 OR RULE 904 OF REGULATION S UNDER THE SECURITIES ACT, OR (4) PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144
THEREUNDER (IF AVAILABLE) OR (5) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS
BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT, AND (B) BY SUBSEQUENT
INVESTORS, AS SET FORTH IN (A) ABOVE AND, IN ADDITION, TO AN INSTITUTIONAL
"ACCREDITED INVESTOR" WITHIN THE MEANING OF SUBPARAGRAPH (A)(1), (2), (3) OR (7)
OF RULE 501 UNDER THE SECURITIES ACT THAT IS ACQUIRING THE SECURITY FOR ITS OWN
ACCOUNT, OR FOR THE ACCOUNT OF SUCH AN INSTITUTIONAL "ACCREDITED INVESTOR," IN A
TRANSACTION EXEMPT FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT, OR
(C) PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS
OF THE SECURITIES ACT, SUBJECT TO THE COMPANY'S AND THE TRUSTEE'S RIGHT PRIOR TO
ANY SUCH OFFER, SALE OR TRANSFER PURSUANT TO CLAUSE (B) OR (C) TO REQUIRE THE
DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/OR OTHER INFORMATION
SATISFACTORY TO EACH OF THEM, AND IN EACH OF THE FOREGOING CASES, A CERTIFICATE
OF TRANSFER IN THE FORM APPEARING ON THE OTHER SIDE OF THIS SECURITY IS
COMPLETED AND DELIVERED BY THE TRANSFEROR TO THE TRUSTEE AND IN EACH CASE IN
ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES
AND OTHER JURISDICTIONS. THE HOLDER HEREOF, BY PURCHASING THIS SECURITY,
REPRESENTS AND AGREES FOR THE BENEFIT OF THE COMPANY THAT IT IS (1) A QUALIFIED
INSTITUTIONAL BUYER OR (2) NOT A U.S. PERSON AND IS OUTSIDE THE UNITED STATES
WITHIN THE MEANING OF (OR AN ACCOUNT SATISFYING THE REQUIREMENTS OF PARAGRAPH
(k) (2) OF RULE 902 UNDER) REGULATION S UNDER THE SECURITIES ACT, AND WILL NOT,
DIRECTLY OR INDIRECTLY, ENGAGE IN ANY HEDGING TRANSACTION WITH REGARD TO THIS
SECURITY EXCEPT AS PERMITTED BY THE SECURITIES ACT, AND WILL ALSO, AND EACH
SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS NOTE

                                      A-2
<PAGE>

FROM IT OF THE RESALE RESTRICTIONS REFERRED TO ABOVE. THIS LEGEND WILL BE
REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE DATE WHICH IS TWO YEARS AFTER
THE LATER OF THE ORIGINAL ISSUANCE OF THE NOTES AND THE LAST DATE ON WHICH THE
COMPANY OR AN AFFILIATE OF THE COMPANY WAS THE OWNER OF THE SECURITY.](2)

----------

(2) These paragraphs to be included only if the Security is a Transfer
    Restricted Security.

                                      A-3
<PAGE>

                           [FORM OF FACE OF SECURITY]

                         DIAMOND OFFSHORE DRILLING, INC.

                           5.15% SENIOR NOTES DUE 2014

Issue Date: August 27, 2004                        Principal Amount: $__________

                                                   CUSIP: [25271C AF 9]
                                                          [U25265 AA 4]

Registered: No. [R-] [S-]                          ISIN: [US25271CAF95]
                                                         [USU25265AA40]

         Diamond Offshore Drilling, Inc., a Delaware corporation (herein called
the "Company", which term includes any successor corporation under the Indenture
hereinafter referred to), for value received, hereby promises to pay to Cede &
Co., or registered assigns, the principal sum of ___________________________
DOLLARS ($___________) on September 1, 2014, [or such greater or lesser amount
as is indicated in the Schedule of Exchanges of Securities on the other side of
this 2014 Note](3) and to pay interest thereon from August 27, 2004 or from the
most recent date to which interest has been paid or duly provided for,
semiannually on March 1 and September 1 in each year (each, an "Interest Payment
Date"), commencing March 1, 2005, at the rate of 5.15% per annum, until the
principal hereof is paid or duly made available for payment. Interest on these
2014 Notes shall be calculated on the basis of a 360-day year consisting of
twelve 30-day months. The interest so payable and punctually paid or duly
provided for on any Interest Payment Date will, as provided in such Indenture,
be paid to the Person in whose name this 2014 Note (or one or more Predecessor
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the February 15 or August 15 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.
Any interest which is payable, but is not punctually paid or duly provided for,
on any Interest Payment Date shall forthwith cease to be payable to the
registered Holder hereof on the relevant Regular Record Date by virtue of having
been such Holder, and may be paid to the Person in whose name this 2014 Note (or
one or more Predecessor Securities) is registered at the close of business on a
Special Record Date for the payment of such Defaulted Interest to be fixed by
the Company, notice whereof shall be given to the Holders of 2014 Notes not less
than 10 days prior to such Special Record Date, or may be paid at any time in
any other lawful manner not inconsistent with the requirements of any securities
exchange on which the 2014 Notes may be listed, and upon such notice as may be
required by such exchange, all as more fully provided in such Indenture.

----------
(3) To be included only if the Security is a Global Security.

                                      A-4
<PAGE>

         Payment of the principal of and interest, if any, on this 2014 Note
will be made at the office or agency of the Company maintained for that purpose
in The City of New York, in such coin or currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts; provided, however, that at the option of the Company, payment of
interest, if any, may be made by check mailed to the address of the Person
entitled thereto as such address shall appear in the Security Register.

         Reference is hereby made to the further provisions of this 2014 Note
set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

         Unless the certificate of authentication hereon has been executed by
the Trustee referred to on the reverse hereof by manual signature, this 2014
Note shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

                                      A-5
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated:
      ------------------------

                                            DIAMOND OFFSHORE DRILLING, INC.

                                            By:
                                               ---------------------------------
                                               Name:
                                                    ----------------------------
                                               Title:
                                                     ---------------------------

-----------------------------
Corporate Secretary

                                      A-6
<PAGE>

                     TRUSTEE'S CERTIFICATE OF AUTHENTICATION

         This is one of the Securities of the series designated therein referred
to in the within-mentioned Indenture.

                                                 JPMORGAN CHASE BANK, as Trustee

                                                 -------------------------------
                                                 Authorized Signature

Date of Authentication:_______________

                                      A-7
<PAGE>

                       [FORM OF REVERSE SIDE OF SECURITY]

                         DIAMOND OFFSHORE DRILLING, INC.

                           5.15% SENIOR NOTES DUE 2014

         This Security is one of a duly authorized issue of senior securities of
the Company (herein called the "Securities"), issued and to be issued in one or
more series under an Indenture, dated as of February 4, 1997, as amended by the
Fourth Supplemental Indenture thereto, dated as of August 27, 2004 (as so
amended, herein called the "Indenture"), between the Company and JPMorgan Chase
Bank (formerly known as The Chase Manhattan Bank), as Trustee (herein called the
"Trustee", which term includes any successor trustee under the Indenture), to
which Indenture and all indentures supplemental thereto reference is hereby made
for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders of the
Securities and of the terms upon which the Securities are, and are to be,
authenticated and delivered. This Security is one of the series designated on
the face hereof (herein called the "2014 Notes"), limited in aggregate principal
amount to $250,000,000 created pursuant to the Fourth Supplemental Indenture.
Capitalized terms used and not otherwise defined in this 2014 Note are used as
defined in the Indenture.

         The 2014 Notes are general unsecured and unsubordinated obligations of
the Company. The Indenture does not limit other indebtedness of the Company,
secured or unsecured.

INTEREST ON OVERDUE AMOUNTS

         If the principal amount hereof or any portion of such principal amount
is not paid when due (whether upon acceleration pursuant to Section 502 of the
Indenture, upon the date set for payment of the Redemption Price as described
under "Optional Redemption" or upon the Stated Maturity of this 2014 Note) or if
interest due hereon, if any (or any portion of such interest), is not paid when
due, then in each such case the overdue amount shall, to the extent permitted by
law, bear interest at the rate of 5.15% per annum, compounded semiannually,
which interest shall accrue from the date such overdue amount was originally due
to the date payment of such amount, including interest thereon, has been made or
duly provided for. All such interest shall be payable as set forth in the
Indenture.

METHOD OF PAYMENT

         Payments in respect of principal of and interest, if any, on the 2014
Notes shall be made by the Company in immediately available funds.

PAYING AGENT AND SECURITY REGISTRAR

         Initially, the Trustee will act as Paying Agent and Security Registrar.
The Company may appoint and change any Paying Agent, Security Registrar or
co-registrar without notice, other than notice to the Trustee, except that the
Company will maintain at least one Paying Agent in the State of New York, City
of New York, Borough of Manhattan, which shall initially be an office or agency
of the Trustee. The Company or any of its Subsidiaries or any of their
Affiliates may act as Paying Agent, Security Registrar or co-registrar.

                                      A-8
<PAGE>

OPTIONAL REDEMPTION

         No sinking fund is provided for the 2014 Notes. The 2014 Notes are
redeemable in whole at any time, or in part from time to time, at the option of
the Company in accordance with the Indenture at a Redemption Price equal to the
greater of (i) 100% of the principal amount of the 2014 Notes to be redeemed or
(ii) the sum, as determined by the Quotation Agent, of the present values of the
principal amount of the 2014 Notes to be redeemed and the remaining scheduled
payments of interest thereon from the Redemption Date to Maturity of the 2014
Notes to be redeemed (the "Remaining Life"), discounted from their respective
scheduled payment dates to the Redemption Date on a semiannual basis (assuming a
360-day year consisting of 30-day months) at the Treasury Rate, plus 20 basis
points (the "Make-Whole Premium"), plus, in either case, accrued and unpaid
interest on the principal amount of the 2014 Notes redeemed to, but excluding,
the Redemption Date.

         If the Company redeems less than all of the Outstanding 2014 Notes, the
Trustee will select the 2014 Notes to be redeemed (i) by lot; (ii) pro rata; or
(iii) by another method the Trustee considers fair and appropriate.

NOTICE OF REDEMPTION

         Notice of redemption will be mailed by first-class mail at least 15
days but not more than 60 days before the Redemption Date to each Holder of the
2014 Notes to be redeemed at its registered address. The 2014 Notes in
denominations larger than $1,000 principal amount may be redeemed in part, but
only in whole multiples of $1,000. On and after the Redemption Date, subject to
the deposit with the Paying Agent of funds sufficient to pay the Redemption
Price and accrued and unpaid interest, all interest shall cease to accrue on the
2014 Notes or portions thereof called for redemption.

TRANSFER

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this 2014 Note is registrable in the Security
Register, upon surrender of this 2014 Note for registration or transfer at the
office or agency in a Place of Payment for the 2014 Notes, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Security Registrar duly executed by, the Holder hereof or his
attorney duly authorized in writing, and thereupon one or more new 2014 Notes,
of any authorized denominations and for the same aggregate principal amount,
executed by the Company and authenticated and delivered by the Trustee, will be
issued to the designated transferee or transferees.

         The Securities are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof. As provided in the
Indenture and subject to certain limitations set forth therein and on the face
of this 2014 Note, 2014 Notes are exchangeable for a like aggregate principal
amount of 2014 Notes of a different authorized denomination as requested by the
Holder surrendering the same.

                                      A-9
<PAGE>

         No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

         Prior to due presentment of this 2014 Note for registration of
transfer, the Company, the Trustee or any agent of the Company or the Trustee
may treat the Person in whose name this 2014 Note is registered as the owner
hereof for all purposes, whether or not this 2014 Note be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

AMENDMENT, SUPPLEMENT AND WAIVER

         The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Company and the Trustee with the
consent of the Holders of a majority in principal amount of the Securities at
the time Outstanding of each series to be affected. The Indenture also contains
provisions permitting the Holders of specified percentages in principal amount
of the Securities of each series at the time Outstanding, on behalf of the
Holders of all Securities of such series, to waive compliance by the Company
with certain past defaults under the Indenture and their consequences. Any such
consent or waiver by the Holder of this 2014 Note shall be conclusive and
binding upon such Holder and upon all future Holders of this 2014 Note and of
any 2014 Notes issued upon the registration of transfer hereof or in exchange
hereof or in lieu hereof, whether or not notation of such consent or waiver is
made upon this 2014 Note.

SUCCESSOR CORPORATION

         When a successor corporation assumes all the obligations of its
predecessor under the 2014 Notes and the Indenture in accordance with the terms
and conditions of the Indenture, the predecessor corporation will (except in
certain circumstances specified in the Indenture) be released from those
obligations.

DEFAULTS AND REMEDIES

         Under the Indenture, Events of Default include (i) default in the
payment of interest when it becomes due and payable or in the payment of any
Liquidated Damages which default in either case continues for a period of 30
days; (ii) default in payment of the principal amount or Redemption Price, as
the case may be, in respect of the Securities when the same becomes due and
payable; (iii) failure by the Company to comply with other agreements in the
Indenture or the Securities, subject to notice and lapse of time; (iv) default
under any bond, debenture, note or other evidence of indebtedness for money
borrowed of the Company or any Subsidiary having an aggregate outstanding
principal amount of in excess of $25,000,000 (excluding such indebtedness of any
Subsidiary other than a Significant Subsidiary, all the indebtedness of which is
nonrecourse to the Company or any other Subsidiary), which default shall be with
respect to payment or shall have resulted in such indebtedness being
accelerated, without such indebtedness being discharged or such acceleration
having been rescinded or annulled, subject to notice and passage of time; and
(v) certain events of bankruptcy, insolvency or reorganization of

                                      A-10
<PAGE>

the Company or any Significant Subsidiary. If an Event of Default with respect
to Securities of this series shall occur and be continuing, the principal amount
through the acceleration date of and accrued and unpaid interest on the
Securities of this series may be declared due and payable in the manner and with
the effect provided in the Indenture. If an Event of Default occurs as a result
of certain events of bankruptcy, insolvency or reorganization of the Company,
the principal amount of and accrued and unpaid interest on the Securities
Outstanding shall become due and payable immediately without any declaration or
other act on the part of the Trustee or any Holder, all as and to the extent
provided in the Indenture.

NO RECOURSE AGAINST OTHERS

         No recourse shall be had for the payment of the principal of or the
interest, if any, on this 2014 Note, for any claim based hereon, or otherwise in
respect hereof, or based on or in respect of the Indenture or any indenture
supplemental thereto, against any incorporator, shareholder, officer or
director, as such, past, present or future, of the Company or of any successor
corporation, whether by virtue of any constitution, statute or rule of law or by
the enforcement of any assessment of penalty or otherwise, all such liability
being, by acceptance hereof and as part of the consideration for the issue
hereof, expressly waived and released.

AUTHENTICATION

         This 2014 Note shall not be valid until the Trustee or an
authenticating agent manually signs the certificate of authentication on the
other side of this 2014 Note.

INDENTURE TO CONTROL; GOVERNING LAW

         In the case of any conflict between the provisions of this 2014 Note
and the Indenture, the provisions of the Indenture shall control.

         THE INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO THE
CONFLICTS OF LAW RULES OF SAID STATE.

ABBREVIATIONS AND DEFINITIONS

         Customary abbreviations may be used in the name of the Holder or an
assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the
entireties), JT TEN (= joint tenants with right of survivorship and not as
tenants in common),

CUST (= Custodian) and U/G/M/A (= Uniform Gifts to Minors Act).

         All terms defined in the Indenture and used in this 2014 Note but not
specifically defined herein are defined in the Indenture and are used herein as
so defined.

                                      A-11
<PAGE>

                      SCHEDULE OF EXCHANGES OF SECURITIES(4)

         The following exchanges or redemptions of a part of this Global
Security have been made:

<Table>
<Caption>
                                               AMOUNT OF DECREASE IN             AMOUNT OF INCREASE IN
                                             PRINCIPAL AMOUNT OF THIS           PRINCIPAL AMOUNT OF THE
            DATE OF TRANSACTION                   GLOBAL SECURITY                   GLOBAL SECURITY
            -------------------              ------------------------           -----------------------
<S>                                          <C>                                <C>

</Table>

----------

(4) This schedule should be included only if the Security is a Global Security.

                                      A-12
<PAGE>

                                   EXHIBIT B-1

                  CERTIFICATE TO BE DELIVERED UPON EXCHANGE OR
               REGISTRATION OF TRANSFER OF RESTRICTED SECURITIES(5)

         Re: 5.15% Senior Notes due 2014 (the "Securities") of Diamond Offshore
         Drilling, Inc.

            This certificate relates to $___________ principal amount of
Securities owned in (check applicable box)

         [ ] book-entry or

         [ ] definitive form

by _________________________________________________(the "Transferor").

         The Transferor has requested a Security Registrar or the Trustee to
exchange or register the transfer of such Securities.

         In connection with such request and in respect of each such Security,
the Transferor does hereby certify that the Transferor is familiar with transfer
restrictions relating to the Securities as provided in Section 102 of the Fourth
Supplemental Indenture dated as of August 27, 2004 (the "Indenture"), between
Diamond Offshore Drilling, Inc. and JPMorgan Chase Bank (formerly known as The
Chase Manhattan Bank), as trustee.

         In connection with any transfer of any of the Securities evidenced by
this certificate occurring prior to the expiration of the period referred to in
Rule 144(k) under the Securities Act after the later of the date of original
issuance of the Securities and the last date, if any, on which such Securities
were owned by the Company or any Affiliate of the Company, the undersigned
confirms that such Securities are being transferred in accordance with its
terms:

CHECK ONE BOX BELOW

         (1) [ ]  to the Company or a subsidiary of the Company; or

         (2) [ ]  pursuant to an effective registration statement under the
                  Securities Act of 1933; or

         (3) [ ]  to a "qualified institutional buyer" (as defined in Rule 144A
                  under the Securities Act of 1933) that purchases for its own
                  account or for the account of a qualified institutional buyer
                  to whom notice is given that such

----------
(5) This certificate should only be included if this Security is a Transfer
    Restricted Security.

                                     B-1-1
<PAGE>

                  transfer is being made in reliance on Rule 144A, in each case
                  pursuant to and in compliance with Rule 144A under the
                  Securities Act of 1933; or

         (4) [ ]  to an institutional accredited investor, defined in Rule
                  501(a)(1), (2), (3) or (7) of Regulation D under the
                  Securities Act; or

         (5) [ ]  pursuant to another available exemption from registration
                  under the Securities Act of 1933.

Unless one of the boxes is checked, the Trustee will refuse to register any of
the Securities evidenced by this certificate in the name of any person other
than the registered holder thereof, provided, however, that if box (4) or (5) is
checked, the Trustee may require, prior to registering any such transfer of the
Securities, such legal opinions, certifications and other information as the
Company has reasonably requested to confirm that such transfer is being made
pursuant to an exemption from, or in a transaction not subject to, the
registration requirements of the Securities Act of 1933, such as the exemption
provided by Rule 144 under such Act.

                                        ----------------------------------------
                                        Signature

Signature Guarantee:

-------------------------------------   ----------------------------------------
Signature must be guaranteed            Signature

              TO BE COMPLETED BY PURCHASER IF (3) ABOVE IS CHECKED.

         The undersigned represents and warrants that it is purchasing this
Security for its own account or an account with respect to which it exercises
sole investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act of
1933, and is aware that the sale to it is being made in reliance on Rule 144A
and acknowledges that it has received such information regarding the Company as
the undersigned has requested pursuant to Rule 144A or has determined not to
request such information and that it is aware that the transferor is relying
upon the undersigned's foregoing representations in order to claim the exemption
from registration provided by Rule 144A.

Dated:
      -------------------------------   ----------------------------------------
                                        NOTICE: To be executed by an executive
                                                officer

                                     B-1-2
<PAGE>

                                   EXHIBIT B-2

             FORM OF LETTER TO BE DELIVERED BY ACCREDITED INVESTORS

Diamond Offshore Drilling, Inc.
15415 Katy Freeway
Houston, Texas  77094

Attention:  Corporate Secretary

JPMorgan Chase Bank, as Security Registrar
Institutional Trust Services
4 New York Plaza
New York, NY 10004
Attention:  Corporate Trust Administration

Dear Sirs:

         We are delivering this letter in connection with the proposed transfer
of $_____________ principal amount of the 5.15% Senior Notes due 2014 (the
"Notes") of Diamond Offshore Drilling, Inc. (the "Company").

         We hereby confirm that:

                  (i) we are an "accredited investor" within the meaning of Rule
         501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act of
         1933, as amended (the "Securities Act"), or an entity in which all of
         the equity owners are "accredited investors" within the meaning of Rule
         501(a)(1), (2), (3) or (7) of Regulation D under the Securities Act (an
         "Institutional Accredited Investor");

                  (ii) the purchase of Notes by us is for our own account or for
         the account of one or more other Institutional Accredited Investors or
         as fiduciary for the account of one or more trusts, each of which is an
         "accredited investor" within the meaning of Rule 501(a)(7) under the
         Securities Act and for each of which we exercise sole investment
         discretion or (B) we are a "bank," within the meaning of Section
         3(a)(2) of the Securities Act, or a "savings and loan association" or
         other institution described in Section 3(a)(5)(A) of the Securities Act
         that is acquiring Notes as fiduciary for the account of one or more
         institutions for which we exercise sole investment discretion;

                  (iii) we will acquire Notes having a minimum principal amount
         of not less than $100,000 for our own account or for any separate
         account for which we are acting;

                  (iv) we have such knowledge and experience in financial and
         business matters that we are capable of evaluating the merits and risks
         of purchasing Notes; and

                                      B-2-1
<PAGE>

                  (v) we are not acquiring Notes with a view to distribution
         thereof or with any present intention of offering or selling Notes,
         except as permitted below; provided that the disposition of our
         property and property of any accounts for which we are acting as
         fiduciary shall remain at all times within our control.

         We understand that the Notes were originally offered and sold in a
transaction not involving any public offering within the United States within
the meaning of the Securities Act and that the Notes have not been registered
under the Securities Act, and we agree, on our own behalf and on behalf of each
account for which we acquire any Notes, that if in the future we decide to
resell or otherwise transfer such Notes prior to the date (the "Resale
Restriction Termination Date") which is two years after the later of the
original issuance of the Notes and the last date on which the Company or an
affiliate of the Company was the owner of the Note, such Notes may be resold or
otherwise transferred only (i) to the Company or any subsidiary thereof, or (ii)
for as long as the Notes are eligible for resale pursuant to Rule 144A, to a
person we reasonably believe to be a "qualified institutional buyer" (as defined
in Rule 144A under the Securities Act) that purchases for its own account or for
the account of such a qualified institutional buyer to which notice is given
that the transfer is being made in reliance on Rule 144A, or (iii) to an
Institutional Accredited Investor that is acquiring the Notes for its own
account, or for the account of such an Institutional Accredited Investor for
investment purposes and not with a view to, or for offer or sale in connection
with, any distribution in violation of the Securities Act, or (iv) pursuant to
another available exemption from registration under the Securities Act (if
applicable), or (v) pursuant to a registration statement which has been declared
effective under the Securities Act and, in each case, in accordance with any
applicable securities laws of any State of the United States or any other
applicable jurisdiction and in accordance with the legends set forth on the
Notes. We further agree to provide any person purchasing any of the Notes other
than pursuant to clause (v) above from us a notice advising such purchaser that
resales of such Notes are restricted as stated herein. We understand that the
trustee or the transfer agent, as the case may be, for the Notes will not be
required to accept for registration of transfer any Notes pursuant to (iii) or
(iv) above except upon presentation of evidence satisfactory to the Company and
the trustee that the foregoing restrictions on transfer have been complied with.
We further understand that any Notes will be in the form of definitive physical
certificates and that such certificates will bear a legend reflecting the
substance of this paragraph other than certificates representing Notes
transferred pursuant to clause (v) above.

         We acknowledge that the Company, others, the Trustee, the Security
Registrar and you will rely upon our confirmations, acknowledgments and
agreements set forth herein, and we agree to notify you promptly in writing if
any of our representations or warranties herein ceases to be accurate and
complete.

                                      B-1-2
<PAGE>

         THIS LETTER SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE
INTERNAL LAWS OF THE STATE OF NEW YORK.

                                        ----------------------------------------
                                        (Name of Purchaser)

                                        By:
                                           -------------------------------------
                                           Name:
                                           Title:
                                           Address:

                                      B-1-3

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