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                                                                  EXHIBIT 10.40



                                SECOND AMENDMENT

          SECOND AMENDMENT, dated as of April 23, 1997 (this "Amendment"), to
the Credit Agreement, dated as of September 30, 1996" (as amended by the Global
Amendment and Assignment and Acceptance, dated as of October 9, 1996 and as may
be further amended, supplemented or otherwise modified from time to time, the
"Credit Agreement"), among RIGCO NORTH AMERICA, L.L.C., a Delaware limited
liability company (the "Borrower"), the several banks and other financial
institutions from time to time parties thereto (the "Lenders"), LEHMAN
COMMERCIAL PAPER INC. ("LCPI"), as Advisor, Syndication Agent and Arranger,
HIBERNIA NATIONAL BANK, as Collateral and Documentation Agent and BHF-BANK
AKTIENGESELLSCHAFT, as Administrative Agent.


                              W I T N E S S E T H

          WHEREAS, pursuant to the Credit Agreement, the Lenders have agreed to
make, and have made, certain Loans to the Borrower; and

          WHEREAS, the Borrower has requested that the Lenders amend, and the
Lenders have agreed to amend, certain of the provisions of the Credit
Agreement, upon the terms and subject to the conditions set forth below;

          NOW, THEREFORE, the parties hereto hereby agree as follows:

          1. Defined Terms. (a) As used herein, terms defined in this Amendment
or in the Credit Agreement are used herein as so defined.

          (b) There shall be added to subsection 1.1 of the Credit Agreement in
the appropriate alphabetical order the following new defined terms:

          "Second Amendment": the Second Amendment, dated as of April 23, 1997,
     to this Agreement.

          "Second Amendment Effective Date": the date of effectiveness of the
     Second Amendment.

          "Additional Term Loan": the term loan made by Lehman Commercial Paper
     Inc. to the Borrower on the Second Amendment Effective Date in the amount
     of $12,000,000 pursuant to the Second Amendment."

          2. Amendment to Section 2.1. Subsection 2.1 of the Credit Agreement
is hereby amended to read in its entirety as follows:

               "2.1 Loans. Subject to the terms and conditions hereof, each
     Lender severally agrees to make a term loan to the Borrower on the Closing
     Date in an amount not to exceed the amount of the Commitment of such
     Lender then in effect, and subject to the terms and conditions set forth
     in the Second Amendment, LCPI agrees to make a term loan to the Borrower
     on the Second Amendment Effective Date in the principal amount of
     $12,000,000 (each such term loan, a "Loan")."



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          3. Additional Term Loan. Subject to the terms and conditions of the
Credit Agreement and this Second Amendment, LCPI agrees to make a term loan
(the "Additional Term Loan") to the Borrower on the Effective Date (as defined
below) in an amount equal to $12,000,000. Schedule I to the Credit Agreement is
hereby amended by adding to the number set forth opposite the name of LCPI, the
amount of $12,000,000. No later than 11:00 A.M., New York City time, on the
Effective Date, LCPI shall make available to the Administrative Agent in
immediately available funds at its office specified in subsection 9.2 of the
Credit Agreement the full amount of the Additional Term Loan. The
Administrative Agent shall, upon receipt of such sums, (i) credit the
Additional Term Loan Collateral Account with $3,846,000 of the proceeds of the
Additional Term Loan and (ii) disburse the remaining $8,154,000 of the
Additional Term Loan in immediately available funds to the account of DeepTech
specified by the Borrower to the Administrative Agent to reimburse DeepTech for
the portion of the Expanded Upgrade Costs (as defined below) advanced by it to
the Borrower prior to the date hereof. Prior to the Second Amendment Effective
Date the Collateral and Documentation Agent shall establish a cash collateral
account (the "Additional Term Loan Collateral Account") over which the
Collateral and Documentation Agent shall have sole dominion and control and
from which the Borrower shall have no right of withdrawal. As provided in the
immediately preceding sentence, on the Second Amendment Effective Date
$3,846,000 of the proceeds of the Additional Term Loan will be deposited in the
Additional Term Loan Collateral Account. Upon presentation to the Collateral
and Documentation Agent of (i) a copy of notices issued in good faith by the
Charterer to the Borrower to the effect that it is undertaking commitments to
obtain goods and services (and providing reasonable detail of such goods and
services) in accordance with the Shoemaker Upgrade Agreement and (ii) the
Borrower's written request to the Collateral and Documentation Agent to release
funds from the Additional Term Loan Collateral Account in the amount specified
in such notices and so long as no Default or Event of Default shall have
occurred and be continuing, the Collateral and Documentation Agent will release
such funds and transfer the same as directed by the Charterer for safekeeping,
pending payment of invoices for such goods and services; provided that no funds
shall be withdrawn from the Additional Term Loan Collateral Account until all
amounts in the Construction Fund Collateral Account and the Restricted Funds
Collateral Subaccount shall have been exhausted in accordance with the terms of
subsection 2.2(b) of the Credit Agreement; and provided, further, upon
completion of the upgrade contemplated by the Shoemaker Upgrade Agreement, the
Collateral and Documentation Agent shall, upon request of the Borrower, release
to the Borrower the sum then on deposit in the Additional Term Loan Collateral
Account and such sum may be used by the Borrower for general working capital
purposes in accordance with the terms of the Credit Agreement.

          4. Amendment to Subsection 2.3. Subsection 2.3 of the Credit
Agreement is hereby amended by deleting the number "$63,250,000" in the
penultimate line thereof and substituting in lieu thereof the number
"$75,250,000".

          5. Amendment to Subsection 2.5(a). Subsection 2.5(a) of the Credit
Agreement is hereby amended by inserting in the third line thereof immediately
after the words "other than" the words "the Additional Term Loan and other
than".

          6. Addition of new Subsection 2.5(d). (a) Subsection 2.5(d) and
subsection 2.5(e) of the Credit Agreement shall be renumbered, "2.5(e)" and
"2.5(f)", respectively, (b) Each reference in the Credit Agreement to
subsection 2.5(d) or subsection 2.5(e) shall be changed to "subsection 2.5(e)"
and "subsection 2.5(f)" respectively and (c) there shall be added to the Credit
Agreement the following new subsection 2.5(d):



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               "(d) Upon receipt by the Borrower of the Mobilization Fees from
     Amoco with respect to the Shoemaker, in the approximate amount of
     $4,180,000 and which are expected to be received in July 1997, 100% of the
     amount thereof shall be applied toward prepayment of the Loans as set
     forth in subsection 2.5(e)."

          7. Amendment to Subsection 5.13. Subsection 5.13 of the Credit
Agreement is hereby amended by deleting the number "$40,000,000" in the last
line thereof and substituting in lieu thereof the number "$48,000,000".

          8. Amendment to Subsection 6.1(a). Subsection 6.1(a) of the Credit
Agreement is hereby amended by inserting immediately after the word "ended" in
the sixth line thereof but immediately prior to the closed parenthetical the
phrase: "and provided, further, to the extent deducted in computing Net Worth
in accordance with GAAP during the fiscal quarter then ended or in any previous
fiscal quarter, Net Worth shall include the amount of any deferred corporate
income taxes of the Borrower (less any reductions in deferred corporate income
taxes of the Borrower during any of such periods) resulting from an election by
the Borrower to be treated as a corporation for U.S. federal income tax
purposes".

          9. Amendment to Subsection 6.1(b). Subsection 6.1(b) of the Credit
Agreement is hereby amended by (i) deleting the ratio "2.00 to 1.00" set forth
opposite September 30, 1997 and substituting in lieu thereof the ratio "1.75 to
1.00" and (ii) deleting the ratio "2.75 to 1.00" set forth opposite December
31, 1997 and substituting in lieu thereof the ratio "2.50 to 1.00".

          10. Waiver. The Lenders hereby waive any Default or Event of Default
which may have occurred prior to the date hereof resulting solely from the
incurrence of a portion of the Expanded Upgrade Costs and the advance of funds
by DeepTech to the Borrower to fund such portion of the Expanded Upgrade Costs.

          11. Fees. In consideration for its agreement to this Amendment, the
Borrower agrees to pay to each Lender which is a signatory hereto, a fee in the
amount of 0.25% of such Lender's Commitment, payable on the date hereof in
immediately available funds.

          12. Effectiveness. The amendments provided for herein shall become
effective on the date (the "Effective Date") of satisfaction of the following
condition precedent:

          (a) The Administrative Agent shall have received counterparts of this
     Second Amendment, duly executed and delivered by the Borrower and each of
     the other parties hereto.

          (b) LCPI shall have received a new promissory note in exchange for
     its existing Note, which includes the amount of the Additional Term Loan.

          (c) The Administrative Agent shall have received, with a counterpart
     for each Lender, a copy of the resolutions, in form and substance
     satisfactory to the Arranger and the Administrative Agent, of the
     Management Committee of the Borrower authorizing (i) the execution,
     delivery and performance of this Second Amendment, (ii) the borrowings
     contemplated hereunder, certified by the Management Committee of the
     Borrower as of the date hereof, which certificate shall be in form and
     substance satisfactory to the Administrative Agent and the Arranger and
     shall state that the resolutions thereby certified have not been amended,
     modified, revoked or rescinded.




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          (d) The Administrative Agent shall have received, with a counterpart
     for each Lender, a certificate of the Management Committee of the
     Borrower, dated the date hereof, as to the incumbency and signature of the
     members or managers of the Borrower executing this Second Amendment
     satisfactory in form and substance to the Administrative Agent and the
     Arranger.

          (e) The reasonable costs and expenses of the Administrative Agent,
     the Collateral and Documentation Agent and the Arranger in connection with
     this Amendment, including without limitation, legal fees and expenses, and
     the fees set forth in paragraph 11 shall have been paid by the Borrower.

          (f) All governmental and third party approvals (including landlords'
     and other consents) necessary or advisable in connection with this Second
     Amendment and the making of the Additional Term Loan shall have been
     obtained and be in full force and effect, and all applicable waiting
     periods shall have expired without any action being taken or threatened by
     any competent authority which would restrain, prevent or otherwise impose
     materially adverse conditions on the Credit Agreement as amended by this
     Second Amendment or the making of the Additional Term Loan.

          (g) The Administrative Agent shall have received the executed legal
     opinions of (i) Akin, Gump, Strauss, Hauer & Feld, counsel to the Borrower
     and (ii) Graham, Thompson & Co., Nassau, special Bahamian counsel to the
     Lenders, each dated the date hereof and in form and substance satisfactory
     to the Administrative Agent.

          (h) The Administrative Agent and LCPI shall have received such
     information with respect to the upgrade and make-ready of the Shoemaker
     which is to be funded by the Additional Term Loan (such increased upgrade
     and make-ready costs, the "Expanded Upgrade Costs") as it shall reasonably
     request.

          (i) The Administrative Agent shall have received evidence in form and
     substance satisfactory to it that all filings, recordings, registrations
     and other actions, including, without limitation, any filings with respect
     to the Mortgages, necessary or, in the opinion of the Administrative
     Agent, desirable to maintain the perfection of the Liens created by the
     Security Documents after giving effect to this Second Amendment shall have
     been completed.

          (j) The Arranger shall have received the results of a recent search
     of the Uniform Commercial Code, judgement and tax lien filings which may
     have been filed with respect to personal property of the Borrower in each
     of the jurisdictions and offices where assets of the Borrower or its
     Subsidiaries are located or recorded, and such search shall reveal no
     material liens on any of the assets of the Borrower or its Subsidiaries
     except for liens permitted by the Loan Documents.

          (k) All limited liability company and other proceedings, and all
     documents, instruments and other legal matters in connection with the
     transactions contemplated by this Second Amendment shall be satisfactory
     in form and substance to the Arranger and the Administrative Agent.

          13. Representations and Warranties. After giving effect to the
amendments contained herein, on the Effective Date, the Borrower hereby
confirms, reaffirms and restates the representations 




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and warranties set forth in Section 3 of the Credit Agreement; provided that
each reference in such Section 3 to "this Agreement" shall be deemed to be a
reference both to this Second Amendment and to the Credit Agreement as amended
by this Second Amendment.

          14. Continuing Effect; No Other Amendments. Except as expressly
amended or waived hereby, all of the terms and provisions of the Credit
Agreement and the other Loan Documents are and shall remain in full force and
effect. The amendments contained herein shall not constitute an amendment or
waiver of any other provision of the Credit Agreement or the other Loan
Documents or for any purpose except as expressly set forth herein.

          15. No Default. Other than as contemplated by paragraph 10 above, no
Default or Event of Default shall have occurred and be continuing as of the
Effective Date after giving effect to this Second Amendment.

          16. Counterparts. This Second Amendment may be executed in any number
of counterparts by the parties hereto, each of which counterparts when so
executed shall be an original, but all the counterparts shall together
constitute one and the same instrument.

          17. GOVERNING LAW. THIS SECOND AMENDMENT SHALL BE GOVERNED BY, AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW
YORK.


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

                                           RIGCO NORTH AMERICA, L.L.C.


                                           By:
                                              Title:


                                           BHF-BANK AKTIENGESELLSCHAFT, as 
                                           Administrative Agent and as a Lender


                                           By:
                                              Title:



                                           By:
                                              Title:


                                           HIBERNIA NATIONAL BANK, as 
                                           Collateral and Documentation
                                           Agent and as a Lender


                                           By:
                                              Title:


                                           LEHMAN COMMERCIAL PAPER INC., as 
                                           Syndication Agent and as a Lender


                                           By:
                                              Title:


                                           VAN KAMPEN AMERICAN CAPITAL PRIME
                                           RATE INCOME TRUST


                                           By:
                                              Title:



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                                           PROTECTIVE LIFE INSURANCE COMPANY


                                           By:
                                              Title:

                                           MERRILL LYNCH PRIME RATE PORTFOLIO

                                           By: MERRILL LYNCH ASSET MANAGEMENT 
                                           L.P., as Investment Adviser


                                           By:
                                              Title:

                                           MERRILL LYNCH SENIOR FLOATING RATE
                                           FUND, INC.


                                           By:
                                              Title:

                                           MERRILL LYNCH DEBT STRATEGIES 
                                           PORTFOLIO

                                           By: MERRILL LYNCH ASSET MANAGEMENT 
                                           L.P., as Investment Adviser


                                           By:
                                              Title:

                                           ML CBO IV (CAYMAN) LTD.

                                           By: Protective Asset Management, 
                                           L.L.C.,
                                           as Collateral Manager


                                           By:
                                              Title: