<PAGE>
                                                                     Exhibit 4.1

                               THIRD AMENDMENT TO
             SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT

     THIS THIRD AMENDMENT TO SECOND AMENDED AND RESTATED LOAN AND SECURITY
AGREEMENT (this "Third Amendment") is made and entered into this 24th day of
October, 2002, by and among FLEET CAPITAL CORPORATION, a Rhode Island
corporation (in its individual capacity, "Fleet"), successor in interest by
assignment to Shawmut Capital Corporation ("Shawmut"), SOUTHWEST BANK OF TEXAS,
N.A., a national banking association ("Southwest"); WHITNEY NATIONAL BANK, a
national banking association ("Whitney"); (Fleet, Whitney and Southwest being
referred to herein collectively as the "Lenders"), Fleet as Agent for the
Lenders (the "Agent"); CANYON OFFSHORE, INC. ("Canyon"), a Texas corporation;
CAL DIVE INTERNATIONAL, INC., a Minnesota corporation ("Cal Dive") and ENERGY
RESOURCE TECHNOLOGY, INC., a Delaware corporation ("ERT") (Cal Dive, ERT, and
Canyon being referred to individually and collectively as the "Borrower").

                                    RECITALS

     A.  The Borrower, Aquatica, Inc., the Agent and the Lenders entered into
         that certain Second Amended and Restated Loan and Security Agreement
         (as amended, modified and supplemented from time to time, the "Loan
         Agreement"), dated as of February 22, 2002.

     B.  The Borrower, Aquatica, Inc., the Agent and the Lenders entered into
         that certain First Amendment to Second Amended and Restated Loan and
         Security Agreement dated August 9, 2002.

     C.  Aquatica, Inc., a Borrower under the Loan Agreement merged with Cal
         Dive, with Cal Dive as the surviving entity, pursuant to the Articles
         of Merger dated June 27, 2002.

     D.  The Borrower, the Agent and the Lenders entered into that certain
         Second Amendment to Second Amended and Restated Loan and Security
         Agreement dated August 30, 2002.

     E.  The Borrower, the Agent and the Lenders have agreed to amend the Loan
         Agreement to, among other things, increase the Revolving Credit
         Commitment, to waive a breach of a covenant and to modify a defined
         term, based upon the terms and conditions set forth in this Third
         Amendment.

     NOW THEREFORE, in consideration of the premises herein contained and other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties, intending to be legally bound, agree as follows:

                                    Article I
                                   Definitions

         1.01              Capitalized terms used in this Third Amendment are
used with the definitions given to them in the Loan Agreement, as amended
hereby, unless otherwise stated.

                                   Article II
                                   Amendments

     2.01         Increase in Revolving Credit Commitment.

     (a)          From and after October 29, 2002, the Revolving Credit
                  Commitment as at any date of determination shall be increased
                  to an amount equal to (a) Seventy Million Dollars
                  ($70,000,000) minus (b) the face amount of all Credit
                  Enhancements outstanding on such date.

     (b)          Each Lender's portion of the Ten Million Dollars ($10,000,000)
                  increase in the Revolving Credit Commitment is set forth on
                  Schedule 1 to this Third Amendment.

     (c)          In consideration for the increase in the Revolving Credit
                  Commitment provided for in this Section 2.01, the Borrower
                  shall pay to the Agent on the date of this Third Amendment,
                  for distribution to the Lenders, a commitment increase fee of
                  $50,000.00.

     (d)          The increase in the Revolving Credit Commitment and each
                  Lender's portion of it shall be evidenced by the Amended and
                  Restated Revolving Credit Notes of the Borrower substantially
                  in the form of Exhibits A-1, A-2 and A-3 attached hereto (the
                  "Restated Notes").
<PAGE>
         2.02              Definition of Borrowing Base.  The definition of
Borrowing Base in Section 1.1 of the Loan Agreement is hereby amended by
modifying subsection (ii) (A) of such definition to read as follows:

         "Eight Million Dollars ($8,000,000) or"

         2.03              Cash Flow Leverage Test. Compliance by the Borrower
with the Cash Flow Leverage Test contained in Section 8.3(a) of the Loan
Agreement is hereby waived for the third calendar quarter of 2002 only. The
waiver contained in this Section 2.03 shall not serve as a precedent to any
future consents, waivers or modifications concerning the Loan Agreement
requested by any party, nor bind the Lenders to agree to any other requests by
the Borrower for modifications or waivers to any provision of the Loan Agreement
or any other Loan Document.

                                   ARTICLE III
                              Conditions Precedent

         3.01              Conditions to Effectiveness.  The effectiveness of
this Third Amendment is subject to the satisfaction of the following conditions
precedent, unless specifically waived in writing by the Agent:

     (a)      The Agent shall have received this Third Amendment and the
              Restated Notes, duly executed by each Borrower;

     (b)      The Agent shall have received a certificate from each Borrower
              certified by the Secretary or Assistant Secretary of each Borrower
              acknowledging (A) that such Borrower's Board of Directors has
              adopted, approved, consented to and ratified resolutions which
              authorize the execution, delivery and performance by such Borrower
              of this Third Amendment and all other documents and agreements
              contemplated herein, and (B) the names of the officers of such
              Borrower authorized to sign this Third Amendment and all other
              documents and agreements contemplated herein (including the
              certificates contemplated herein) together with specimen
              signatures of such officers;

     (c)      The representations and warranties contained in this Third
              Amendment and in the Loan Agreement and the other Loan Documents
              shall be true and correct as of the date hereof, as if made on the
              date hereof;

     (d)      No Default or Event of Default shall have occurred and be
              continuing, unless such Default or Event of Default has been
              specifically waived in writing by the Agent; and

     (e)      All corporate proceedings taken in connection with the
              transactions contemplated by this Third Amendment and all
              documents, instruments and other legal matters incident thereto
              shall be satisfactory to the Agent and its legal counsel.

     (f)      The Agent shall have received the consent of Bank One N.A. as
              agent of the Gunnison Platform credit facility to this Third
              Amendment in form and substance satisfactory to the Agent.

                                   ARTICLE IV
                  Ratifications, Representations and Warranties

         4.01              Ratifications. The terms and provisions set forth in
this Third Amendment shall modify and supersede all inconsistent terms and
provisions set forth in the Loan Agreement and the other Loan Documents, and,
except as expressly modified and superseded by this Third Amendment, the terms
and provisions of the Loan Agreement and the other Loan Documents are ratified
and confirmed and shall continue in full force and effect. The Borrower, the
Agent and the Lenders agree that the Loan Agreement and the other Loan
Documents, as amended by this Third Amendment, shall continue to be legal,
valid, binding and enforceable in accordance with their respective terms.

         4.02              Representations and Warranties. Each Borrower hereby
represents and warrants to the Agent and the Lenders that (a) the execution,
delivery and performance of this Third Amendment and any and all other Loan
Documents executed or delivered in connection herewith have been authorized by
all requisite corporate action on the part of such Borrower and will not violate
the Articles or Certificate of Incorporation or Bylaws of such Borrower; (b)
presently effective resolutions of such Borrower's Board of Directors authorize
the execution, delivery and performance of this Third Amendment and any and all
other Loan Documents executed and/or delivered in connection herewith; (c) the
representations and warranties contained in the Loan Agreement, as amended by
this Third Amendment, and any other Loan Document are true and correct on and as
of the date hereof
<PAGE>
and on and as of the date of execution hereof as though made on and as of each
such date; (d) no Default or Event of Default under the Loan Agreement, as
amended by this Third Amendment, has occurred and is continuing, unless such
Default or Event of Default has been specifically waived in writing by the Agent
on behalf of the Lenders; (e) each Borrower is in full compliance with all
covenants and agreements contained in the Loan Agreement and the other Loan
Documents, as amended by this Third Amendment; and (f) no Borrower has amended
its Articles or Certificate of Incorporation or its Bylaws since the date of the
Loan Agreement, except for such amendments, if any, which are attached as
exhibits to the certificates referred to in Section 3.01(b) above.

                                   ARTICLE V
                            Miscellaneous Provisions

         5.01              Survival of Representations and Warranties. All
representations and warranties made in the Loan Agreement or any other Loan
Document, including, without limitation, any document furnished in connection
with this Third Amendment, shall survive the execution and delivery of this
Third Amendment and the other Loan Documents in accordance with Section 7.3 of
the Loan Agreement, and no investigation by the Agent or the Lenders or any
closing shall affect the representations and warranties or the right of the
Agent or the Lenders to rely upon them.

         5.02              Reference to Loan Documents. Each of the Loan
Agreement and the other Loan Documents, and any and all other agreements,
documents or instruments now or hereafter executed and delivered pursuant to the
terms hereof or pursuant to the terms of the Loan Documents, as amended hereby,
are hereby amended so that any reference in the Loan Agreement and such other
Loan Documents to any other Loan Document shall mean a reference to the Loan
Documents as amended by this Third Amendment.

         5.03              Expenses of Lender. As provided in the Loan
Agreement, the Borrower agrees to pay on demand all costs and expenses incurred
by the Agent and the Lenders in connection with the preparation, negotiation,
and execution of this Third Amendment and the other Loan Documents executed
pursuant hereto and any and all amendments, modifications, and supplements
thereto, including, without limitation, the costs and fees of the Agent's legal
counsel, and all costs and expenses incurred by the Agent and the Lenders in
connection with the enforcement or preservation of any rights under the Loan
Agreement, as amended by this Third Amendment, or any other Loan Document,
including, without limitation, the costs and fees of the Agent's and the
Lenders' legal counsel.

         5.04              Severability. Any provision of this Third Amendment
held by a court of competent jurisdiction to be invalid or unenforceable shall
not impair or invalidate the remainder of this Third Amendment and the effect
thereof shall be confined to the provision so held to be invalid or
unenforceable.

         5.05              Successors and Assigns. This Third Amendment is
binding upon and shall inure to the benefit of the Agent, the Lenders and the
Borrower and their respective successors and assigns, except that the Borrower
may not assign or transfer any of its rights or obligations hereunder without
the prior written consent of the Agent.

         5.06              Counterparts.  This Third Amendment may be executed
in one or more counterparts, each of which when so executed shall be deemed to
be an original, but all of which when taken together shall constitute one and
the same instrument.

         5.07              Effect of Waiver. No consent or waiver, express or
implied, by the Agent or the Lenders to or for any breach of or deviation from
any covenant or condition by the Borrower shall be deemed a consent to or waiver
of any other breach of the same or any other covenant, condition or duty.

         5.08              Headings.  The headings, captions, and arrangements
used in this Third Amendment are for convenience only and shall not affect the
interpretation of this Third Amendment.

         5.09              Applicable Law.  THIS THIRD AMENDMENT SHALL BE DEEMED
TO HAVE BEEN MADE AND TO BE PERFORMABLE IN AND SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF TEXAS.
<PAGE>
         5.10              Final Agreement. THE LOAN AGREEMENT AND THE OTHER
LOAN DOCUMENTS, EACH AS AMENDED BY THIS THIRD AMENDMENT, REPRESENT THE ENTIRE
EXPRESSION OF THE PARTIES WITH RESPECT TO THE SUBJECT MATTER HEREOF ON THE DATE
THIS THIRD AMENDMENT IS EXECUTED. THE LOAN AGREEMENT AND THE OTHER LOAN
DOCUMENTS, AS AMENDED BY THIS THIRD AMENDMENT 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. NO MODIFICATION,
RESCISSION, WAIVER, RELEASE OR AMENDMENT OF ANY PROVISION OF THIS THIRD
AMENDMENT SHALL BE MADE, EXCEPT BY A WRITTEN AGREEMENT SIGNED BY THE BORROWER
AND THE LENDERS.

         5.11              Release. EACH BORROWER HEREBY ACKNOWLEDGES THAT AS OF
THE DATE HEREOF IT HAS NO DEFENSE, COUNTERCLAIM, OFFSET, CROSS-COMPLAINT, CLAIM
OR DEMAND OF ANY KIND OR NATURE WHATSOEVER THAT CAN BE ASSERTED TO REDUCE OR
ELIMINATE ALL OR ANY PART OF ITS LIABILITY TO REPAY THE OBLIGATIONS OR TO SEEK
AFFIRMATIVE RELIEF OR DAMAGES OF ANY KIND OR NATURE FROM THE LENDERS. THE
BORROWER HEREBY VOLUNTARILY AND KNOWINGLY RELEASES AND FOREVER DISCHARGES THE
AGENT AND THE LENDERS, THEIR PREDECESSORS, OFFICERS, DIRECTORS, EMPLOYEES,
AGENTS, SUCCESSORS AND ASSIGNS, FROM ALL POSSIBLE CLAIMS, DEMANDS, ACTIONS,
CAUSES OF ACTION, DAMAGES, COSTS, EXPENSES, AND LIABILITIES WHATSOEVER, KNOWN OR
UNKNOWN, ANTICIPATED OR UNANTICIPATED, SUSPECTED OR UNSUSPECTED, FIXED,
CONTINGENT, OR CONDITIONAL, AT LAW OR IN EQUITY (EXCEPT FOR POSSIBLE CLAIMS,
DEMANDS, ACTIONS, CAUSES OF ACTION, DAMAGES, COSTS, EXPENSES AND LIABILITIES
CAUSED BY THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF THE AGENT OR THE
LENDERS, THEIR PREDECESSORS, AGENTS, EMPLOYEES, SUCCESSORS AND ASSIGNS),
ORIGINATING IN WHOLE OR IN PART ON OR BEFORE THE DATE THIS THIRD AMENDMENT IS
EXECUTED, WHICH THE BORROWER MAY NOW OR HEREAFTER HAVE AGAINST THE AGENT OR THE
LENDERS, THEIR PREDECESSORS, OFFICERS, DIRECTORS, EMPLOYEES, AGENTS, SUCCESSORS
AND ASSIGNS), IF ANY, AND IRRESPECTIVE OF WHETHER ANY SUCH CLAIMS ARISE OUT OF
CONTRACT, TORT, VIOLATION OF LAW OR REGULATIONS, OR OTHERWISE, AND ARISING FROM
ANY LOANS, INCLUDING, WITHOUT LIMITATION, ANY CONTRACTING FOR, CHARGING, TAKING,
RESERVING, COLLECTING OR RECEIVING INTEREST IN EXCESS OF THE HIGHEST LAWFUL RATE
APPLICABLE, THE EXERCISE OF ANY RIGHTS AND REMEDIES UNDER THE LOAN AGREEMENT OR
OTHER LOAN DOCUMENTS, AND NEGOTIATION FOR AND EXECUTION OF THIS THIRD AMENDMENT.

   IN WITNESS WHEREOF, this Third Amendment has been executed as of October 24,
2002.

                           CAL DIVE INTERNATIONAL, INC.


                           By: /s/   A. WADE PURSELL
                           -------------------------------------------------
                           A. Wade Pursell
                           Senior Vice President and Chief Financial Officer


                           ENERGY RESOURCE TECHNOLOGY, INC.


                           By: /s/   A. WADE PURSELL
                           -------------------------------------------------
                           A. Wade Pursell
                           Senior Vice President and Chief Financial Officer


                           CANYON OFFSHORE, INC.
<PAGE>
                           By: /s/   A. WADE PURSELL
                           -------------------------------------------------
                           A. Wade Pursell
                           Vice President and Chief Financial Officer


                           FLEET CAPITAL CORPORATION, as Agent for the Lenders


                           By:  /s/  E. JAMES BECKEMEIER
                           -------------------------------------------------
                           Name:  E. James Beckemeier
                           Title:  Vice President


                           FLEET CAPITAL CORPORATION


                           By:  /s/  E. JAMES BECKEMEIER
                           -------------------------------------------------
                           Name:  E. James Beckemeier
                           Title:  Vice President


                           SOUTHWEST BANK OF TEXAS, N.A.


                           By:  /s/  PAUL W. COLE
                           -------------------------------------------------
                           Name:  Paul W. Cole
                           Title:  Vice President


                           WHITNEY NATIONAL BANK


                           By:  /s/  HARRY C. STAHEL
                           -------------------------------------------------
                           Name:  Harry E. Stahel
                           Title:  Senior Vice President
<PAGE>
                          SCHEDULE 1 TO THIRD AMENDMENT

<TABLE>
<CAPTION>
                  Lender                              Portion of Increase in Revolving Credit Commitment
                  ------                              --------------------------------------------------
<S>                                                   <C>
                  Fleet Capital Corporation                             USD 4,000,000

                  Whitney National Bank                                 USD 5,000,000

                  Southwest Bank of Texas, N.A.                         USD 1,000,000
</TABLE>
<PAGE>
                                                                     Exhibit A-1

                   AMENDED AND RESTATED REVOLVING CREDIT NOTE

$39,000,000.00                                                  October 24, 2002
Houston, Texas

     FOR VALUE RECEIVED, the undersigned (hereinafter referred to collectively
as "Borrower"), hereby PROMISES TO PAY to the order of FLEET CAPITAL
CORPORATION, a Rhode Island corporation ("Lender"), or its registered assigns,
at the office of Fleet Capital Corporation, as Agent for such Lender, or at such
other place in the United States of America as the holder of this Note may
designate from time to time in writing, in lawful money of the United States of
America and in immediately available funds, the principal amount of THIRTY-NINE
MILLION AND NO/100 Dollars ($39,000,000.00), or such lesser principal amount as
may be outstanding pursuant to the Loan Agreement (as hereinafter defined) with
respect to the Revolving Credit Loan, together with interest on the unpaid
principal amount of this Note outstanding from time to time.

     This Note is one of the Notes referred to in, and issued pursuant to, that
certain Second Amended and Restated Loan and Security Agreement dated as of
February 22, 2002, as amended, by and among Borrower, the lenders signatory
thereto (including Lender) and Fleet Capital Corporation ("FCC"), as agent for
such Lenders (FCC in such capacity, the "Agent") (as amended, modified or
restated, from time to time, the "Loan Agreement"), and is entitled to all of
the benefits and security of the Loan Agreement. All of the terms, covenants and
conditions of the Loan Agreement and the other Loan Documents are hereby made a
part of this Note and are deemed incorporated herein in full. All capitalized
terms herein, unless otherwise defined, unless otherwise specifically defined in
this Note, shall have the meanings ascribed to them in the Loan Agreement.

     The principal amount of the indebtedness evidenced hereby shall be payable
in the amounts and on the dates specified in the Loan Agreement and, if not
sooner paid in full, on the last day of the Term, unless the term hereof is
extended in accordance with the Loan Agreement. Interest thereon shall be paid
until such principal amount is paid in full at such interest rates and at such
times as are specified in the Loan Agreement.

     Upon and after the occurrence, and during the continuation, of an Event of
Default, this Note shall or may, as provided in the Loan Agreement, become or be
declared immediately due and payable.

     The right to receive principal of, and stated interest on, this Note may
only be transferred in accordance with the provisions of the Loan Agreement.

     Demand, presentment, protest and notice of nonpayment and protest are
hereby waived by Borrower.

     This Note is the amendment, restatement, renewal and extension of the
promissory note of the Borrower dated February 22, 2002 and evidences among
other things, the increase in the Lenders portion of the increased Revolving
Credit Commitment as agreed by the Lenders and the Borrower in the Third
Amendment to the Loan Agreement dated October 24, 2002.

     This Note shall be interpreted, governed by, and construed in accordance
with, the internal laws of the State of Texas.

                           CAL DIVE INTERNATIONAL, INC.,
                           a Minnesota corporation

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

                           ENERGY RESOURCE TECHNOLOGY, INC.,
                           a Delaware corporation

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

                           CANYON OFFSHORE, INC.,
                           a Texas corporation

                           By:
                              --------------------------------------------------
                           Name:
                                ------------------------------------------------
                           Title:
                                 -----------------------------------------------
<PAGE>
                                                                     Exhibit A-2

                   AMENDED AND RESTATED REVOLVING CREDIT NOTE

$25,000,000.00                                                  October 24, 2002
Houston, Texas

     FOR VALUE RECEIVED, the undersigned (hereinafter referred to collectively
as "Borrower"), hereby PROMISES TO PAY to the order of WHITNEY NATIONAL BANK, a
national banking association ("Lender"), or its registered assigns, at the
office of Fleet Capital Corporation, as Agent for such Lender, or at such other
place in the United States of America as the holder of this Note may designate
from time to time in writing, in lawful money of the United States of America
and in immediately available funds, the principal amount of TWENTY-FIVE MILLION
AND NO/100 Dollars ($25,000,000.00), or such lesser principal amount as may be
outstanding pursuant to the Loan Agreement (as hereinafter defined) with respect
to the Revolving Credit Loan, together with interest on the unpaid principal
amount of this Note outstanding from time to time.

     This Note is one of the Notes referred to in, and issued pursuant to, that
certain Second Amended and Restated Loan and Security Agreement dated as of
February 22, 2002, as amended, by and among Borrower, the lenders signatory
thereto (including Lender) and Fleet Capital Corporation ("FCC"), as agent for
such Lenders (FCC in such capacity, the "Agent") (as amended, modified or
restated, from time to time, the "Loan Agreement"), and is entitled to all of
the benefits and security of the Loan Agreement. All of the terms, covenants and
conditions of the Loan Agreement and the other Loan Documents are hereby made a
part of this Note and are deemed incorporated herein in full. All capitalized
terms herein, unless otherwise defined, unless otherwise specifically defined in
this Note, shall have the meanings ascribed to them in the Loan Agreement.

     The principal amount of the indebtedness evidenced hereby shall be payable
in the amounts and on the dates specified in the Loan Agreement and, if not
sooner paid in full, on the last day of the Term, unless the term hereof is
extended in accordance with the Loan Agreement. Interest thereon shall be paid
until such principal amount is paid in full at such interest rates and at such
times as are specified in the Loan Agreement.

     Upon and after the occurrence, and during the continuation, of an Event of
Default, this Note shall or may, as provided in the Loan Agreement, become or be
declared immediately due and payable.

     The right to receive principal of, and stated interest on, this Note may
only be transferred in accordance with the provisions of the Loan Agreement.

     Demand, presentment, protest and notice of nonpayment and protest are
hereby waived by Borrower.

     This Note is the amendment, restatement, renewal and extension of the
promissory note of the Borrower dated February 22, 2002 and evidences among
other things, the increase in the Lenders portion of the increased Revolving
Credit Commitment as agreed by the Lenders and the Borrower in the Third
Amendment to the Loan Agreement dated October 24, 2002.

     This Note shall be interpreted, governed by, and construed in accordance
with, the internal laws of the State of Texas.

                           CAL DIVE INTERNATIONAL, INC.,
                           a Minnesota corporation

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

                           ENERGY RESOURCE TECHNOLOGY, INC.,
                           a Delaware corporation

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

                           CANYON OFFSHORE, INC.,
                           a Texas corporation

                           By:
                              --------------------------------------------------
                           Name:
                                ------------------------------------------------
                           Title:
                                 -----------------------------------------------
<PAGE>
                                                                     Exhibit A-3

                   AMENDED AND RESTATED REVOLVING CREDIT NOTE

$6,000,000.00                                                   October 24, 2002
Houston, Texas

     FOR VALUE RECEIVED, the undersigned (hereinafter referred to collectively
as "Borrower"), hereby PROMISES TO PAY to the order of SOUTHWEST BANK OF TEXAS,
N.A., a national banking association ("Lender"), or its registered assigns, at
the office of Fleet Capital Corporation, as Agent for such Lender, or at such
other place in the United States of America as the holder of this Note may
designate from time to time in writing, in lawful money of the United States of
America and in immediately available funds, the principal amount of SIX MILLION
AND NO/100 Dollars ($6,000,000.00), or such lesser principal amount as may be
outstanding pursuant to the Loan Agreement (as hereinafter defined) with respect
to the Revolving Credit Loan, together with interest on the unpaid principal
amount of this Note outstanding from time to time.

     This Note is one of the Notes referred to in, and issued pursuant to, that
certain Second Amended and Restated Loan and Security Agreement dated as of
February 22, 2002, as amended, by and among Borrower, the lenders signatory
thereto (including Lender) and Fleet Capital Corporation ("FCC"), as agent for
such Lenders (FCC in such capacity, the "Agent") (as amended, modified or
restated, from time to time, the "Loan Agreement"), and is entitled to all of
the benefits and security of the Loan Agreement. All of the terms, covenants and
conditions of the Loan Agreement and the other Loan Documents are hereby made a
part of this Note and are deemed incorporated herein in full. All capitalized
terms herein, unless otherwise defined, unless otherwise specifically defined in
this Note, shall have the meanings ascribed to them in the Loan Agreement.

     The principal amount of the indebtedness evidenced hereby shall be payable
in the amounts and on the dates specified in the Loan Agreement and, if not
sooner paid in full, on the last day of the Term, unless the term hereof is
extended in accordance with the Loan Agreement. Interest thereon shall be paid
until such principal amount is paid in full at such interest rates and at such
times as are specified in the Loan Agreement.

     Upon and after the occurrence, and during the continuation, of an Event of
Default, this Note shall or may, as provided in the Loan Agreement, become or be
declared immediately due and payable.

     The right to receive principal of, and stated interest on, this Note may
only be transferred in accordance with the provisions of the Loan Agreement.

     Demand, presentment, protest and notice of nonpayment and protest are
hereby waived by Borrower.

     This Note is the amendment, restatement, renewal and extension of the
promissory note of the Borrower dated February 22, 2002 and evidences among
other things, the increase in the Lender's portion of the increased Revolving
Credit Commitment as agreed by the Lenders and the Borrower in the Third
Amendment to the Loan Agreement dated October 24, 2002.

     This Note shall be interpreted, governed by, and construed in accordance
with, the internal laws of the State of Texas.

                           CAL DIVE INTERNATIONAL, INC.,
                           a Minnesota corporation

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

                           ENERGY RESOURCE TECHNOLOGY, INC.,
                           a Delaware corporation

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

                           CANYON OFFSHORE, INC.,
                           a Texas corporation

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