EXHIBIT 10.173
                                                                         
              FIFTH AMENDMENT TO LETTER OF CREDIT AGREEMENT
                                    
          FIFTH  AMENDMENT  TO LETTER OF CREDIT AGREEMENT,  dated  as  of
February  22,  1999 (this "Amendment"), among R&B FALCON  CORPORATION,  a
Delaware corporation (the "Obligor") and CHRISTIANIA BANK OG KREDITKASSE,
NEW  YORK BRANCH (the "Bank").  All capitalized terms used herein and not
otherwise defined shall have the meanings provided such terms in the  L/C
Agreement (as defined below).

                          W I T N E S S E T H :
                                    
          WHEREAS,  the Bank and the Obligor are parties to a  Letter  of
Credit Agreement, dated as of December 30, 1996 (as amended to date,  the
"L/C Agreement"); and

          WHEREAS, the parties thereto and hereto wish to amend  the  L/C
Agreement as herein provided;

          NOW, THEREFORE, it is agreed:

I.  Amendments to L/C Agreement and Other Terms.

          1.   Section  6  of  the  L/C Agreement is  hereby  amended  by
inserting  the  following new Section 6.11 immediately following  Section
6.10:

          6.11  Backstop Letter of Credit.  The Obligor agrees that on or
     before March 31, 1999, it shall deliver to the Bank, as beneficiary,
     an  irrevocable sight letter of credit issued by a bank satisfactory
     to  the Bank and otherwise in form and substance satisfactory to the
     Bank,  which letter of credit shall support the Obligations  of  the
     Obligor hereunder, with such letter of credit to have an expiry date
     not earlier than one month after the Maturity Date.
     
          2.   Section 7.01 of the L/C Agreement is hereby amended by (i)
deleting  clause (e) thereof in its entirety and inserting the  following
new clause (e) in lieu thereof:

          (e)   Indebtedness of the Obligor created under the R&B  Falcon
     Credit  Agreement  in  an  aggregate  principal  amount  not  exceed
     $200,000,000.
     
,  (ii)  deleting the word "and" at the end of clause (h)  thereof,  (ii)
redesignating  clause (i) thereof as clause (j), and (iii) inserting  the
following new clause (i) immediately following clause (h) thereof:

          (i)   Senior  unsecured Indebtedness of the Obligor  (including
     any refinancing thereof, provided that any such refinancing does not
     increase the principal amount thereof beyond that outstanding on the
     date  of such refinancing) in an aggregate principal amount  not  to
     exceed $350,000,000; provided that such Indebtedness (or refinancing
     thereof, as the case may be) shall at all times (i) be unsecured and
     (ii)  have  a  maturity date not earlier than  one  year  after  the
     Maturity  Date  (as such term is defined from time to time)  (except
     for  any refinancing which results solely in the conversion of  such
     Indebtedness  into,  or  exchange for,  other  Indebtedness  of  the
     Obligor,  in  an  aggregate  principal amount  not  to  exceed  that
     outstanding on the date of such refinancing, which is unsecured  and
     has  a  maturity date not earlier than one year after  the  Maturity
     Date (as such term is defined from time to time)); and
     
          3.   Section 7.11 of the L/C Agreement is hereby amended by (i)
deleting clause (iii) thereof in its entirety and inserting the following
new clause (iii) in lieu thereof:

     and  (iii)  sales  of properties and assets which shall  not  exceed
     $50,000,000 in fair market value in the aggregate in any fiscal year
     of  the  Obligor;  provided that in addition to the above  permitted
     asset sales, the Obligor and its Subsidiaries shall be permitted  to
     sell Non-Core Assets not exceeding $250,000,000 in fair market value
     in the aggregate in any fiscal year of the Obligor.
     
          4.   Section  7.10  of the L/C Agreement is hereby  amended  by
deleting  said  section in its entirety and inserting the  following  new
Section 7.10 in lieu thereof:

          7.10.   Interest Coverage Ratio.  The Obligor will  not  permit
     its  Interest Coverage Ratio at the end of any fiscal quarter of the
     Obligor  (calculated quarterly at the end of each fiscal quarter  of
     the  Obligor)  to be less than (i) at any time prior to  January  1,
     2000,  1.50:1.00  and (ii) at any time thereafter,  1.75:1.00.   For
     purposes  of this Section 7.10, the "Interest Coverage Ratio"  shall
     mean  the  ratio of (x) EBITDA for the four fiscal quarters  of  the
     Obligor ending on such date to (y) Consolidated Interest Expense for
     the four fiscal quarters of the Obligor ending on such date.
     
          5.   Section  7.13  of the L/C Agreement is hereby  amended  by
deleting  said  section in its entirety and inserting the  following  new
Section 7.13 in lieu thereof:

          Section  7.13   Restriction  on  Certain  Debt  Payments.   The
     Obligor  shall not (i) repay any indebtedness incurred  pursuant  to
     Section 7.01(h) except out of net proceeds from the issuance by  the
     Obligor of (x) capital stock permitted to be issued hereunder or (y)
     refinancing  Indebtedness  permitted pursuant  to  Section  7.01(h);
     provided  that, so long as no Default or Event of Default exists  or
     would  result immediately after giving effect to such payment,  this
     Section  7.13(i)  shall not be deemed to prevent  the  Obligor  from
     making  regularly  scheduled payments of accrued  interest  on  such
     Indebtedness  or  (ii)  make any optional or  voluntary  payment  or
     prepayment  on  or redemption or acquisition for value  of,  or  any
     prepayment  or redemption as a result of any asset sale,  change  of
     control  or  similar event of any indebtedness incurred pursuant  to
     Section 7.01(i).
     
          6.   Section  9 of the L/C Agreement is hereby amended  by  (i)
deleting  the  definitions of "EBITDA" and "Eurodollar Margin"  appearing
therein  and  (ii) inserting the following new definitions in appropriate
alphabetical order:

               "Consolidated  Interest  Expense"  shall  mean,  for   any
         period,  total interest expense (including that attributable  to
         Capital  Lease Obligations) of the Obligor and its  Subsidiaries
         in   accordance  with  GAAP  (provided  that,  in   any   event,
         Consolidated  Interest  Expense shall  not  include  capitalized
         interest)   on  a  consolidated  basis  with  respect   to   all
         outstanding  Indebtedness of the Obligor and  its  Subsidiaries,
         including,  without limitation, all commissions, discounts,  and
         other  fees and charges owed with respect to letters  of  credit
         and bankers' acceptance financing.
         
               "EBITDA"   shall  mean,  for  any  period,  the   sum   of
         Consolidated  Net  Income  for such period  plus  the  following
         expenses  or  charges to the extent deducted  from  Consolidated
         Net  Income  in  such period: interest, dividends  on  preferred
         stock,   taxes,   depreciation,  depletion   and   amortization.
         Notwithstanding the foregoing, the calculation of  EBITDA  shall
         not  take  into account any extraordinary gains or  losses,  any
         non-cash items, or any non-recurring gains or charges.
         
               "Non-Core  Assets"  shall  mean  (i)  the  drilling   rigs
         Seillean,  Iolair,  Peregrine VI (Hull), Peregrine  VIII  (Hull)
         and  Rig  82,  (ii)  Equipment Packages  for  Peregrine  VI  and
         Peregrine  VIII  and  (iii) four supply boats  located  in  West
         Africa   on  the  Fifth  Amendment  Effective  Date,   each   as
         determined on the Fifth Amendment Effective Date.
         
               "Fifth  Amendment" shall mean the Fifth Amendment to  this
         Agreement, dated as of February 22, 1999.
         
               "Fifth  Amendment Effective Date" shall have  the  meaning
         provided in the Fifth Amendment.
         
          7.   Notwithstanding  anything to  the  contrary  contained  in
Section  1.01 of the L/C Agreement or in any other provision thereof,  as
of the Fifth Amendment Effective Date, (i) the Bank shall not be required
to issue, nor shall the Obligor be entitled to request, any new Letter of
Credit  under the L/C Agreement and (ii) no Letter of Credit  outstanding
under  the L/C Agreement on the Fifth Amendment Effective Date  shall  be
extended beyond the then applicable expiry date of such Letter of Credit,
in  each case without the express prior written consent of the Bank.   In
addition,  as  of  the  Fifth Amendment Effective  Date,  the  Unutilized
Commitment shall be deemed to be $0 for all purposes of the L/C Agreement
(including, without limitation, for purposes of Section 2.01(b)).

          8.   Pursuant  to Section 7.12 of the L/C Agreement,  the  Bank
hereby  consents  to  the  Fourth Amendment  to  the  R&B  Falcon  Credit
Agreement,  and the granting of the collateral contemplated  therein,  in
the  form  delivered  to the Bank prior to the Fifth Amendment  Effective
Date.

II  Miscellaneous Provisions.

          1.   In  order to induce the Bank to enter into this Amendment,
the Obligor hereby represents and warrants that:

          (a)   no  Default or Event of Default exists as  of  the  Fifth
     Amendment Effective Date both before and after giving effect to this
     Amendment; and
     
          (b)  all of the representations and warranties contained in the
     L/C Agreement and the other Credit Documents are true and correct in
     all  material  respects on the Fifth Amendment Effective  Date  both
     before  and  after giving effect to this Amendment,  with  the  same
     effect  as though such representations and warranties had been  made
     on and as of the Fifth Amendment Effective Date (it being understood
     that any representation or warranty made as of a specific date shall
     be  true  and  correct in all material respects as of such  specific
     date).
     
          2.   This  Amendment  is  limited as specified  and  shall  not
constitute a modification, acceptance or waiver of any other provision of
the L/C Agreement or any other Credit Document.

          3.    This   Amendment  may  be  executed  in  any  number   of
counterparts   and   by  the  different  parties   hereto   on   separate
counterparts,  each  of  which counterparts when executed  and  delivered
shall be an original, but all of which shall together constitute one  and
the same instrument.  A complete set of counterparts shall be lodged with
the Obligor and the Bank.

          4.   THIS  AMENDMENT  AND  THE RIGHTS AND  OBLIGATIONS  OF  THE
PARTIES HERETO SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY  THE
LAW OF THE STATE OF NEW YORK.

          5.   This Amendment shall become effective as of 12:01 AM  (New
York  time) on the date (the "Fifth Amendment Effective Date")  when  (i)
each  of the Obligor and the Bank shall have signed a counterpart  hereof
(whether  the  same or different counterparts) and shall  have  delivered
(including by way of facsimile transmission) the same to the Bank at  its
Notice Office, and (ii) the Obligor shall have consummated an issuance of
its  convertible  preferred stock and received cash  proceeds  from  such
issuance of not less than $250,000,000 less fees and commissions.

          6.   From  and  after the Fifth Amendment Effective  Date,  all
references in the L/C Agreement and each of the other Credit Documents to
the  L/C  Agreement shall be deemed to be references to the L/C Agreement
as amended hereby.

          IN WITNESS WHEREOF, the parties hereto have caused their duly
authorized officers to execute and deliver this Amendment as of the date
first above written.

                              R&B FALCON CORPORATION
                              
                              
                              By:_________________________
                                    Title:
                              
                              
                              CHRISTIANIA BANK OG KREDITKASSE, NEW YORK
                              BRANCH
                              
                              
                              By:_________________________
                                    Title:
                              
                              By:_________________________
                                    Title: