Morgan Guaranty Trust Company of New York, as Agent under the Credit Agreement referred to below 60 Wall Street New York, NY 10260

EXHIBIT 4.05
                                                                EXHIBIT D


                                 EXTENSION AGREEMENT

      Oceaneering International, Inc.
      00000 Xxxx Xxx Xxxxx, Xxxxx 000
      Xxxxxxx, Xxxxx  00000    

      Xxxxxx Guaranty Trust Company      
          of New York, as Agent under     
          the Credit Agreement            
          referred to below               
      00 Xxxx Xxxxxx                     
      Xxx Xxxx, XX  00000

      Gentlemen:

         The undersigned hereby agree to extend, effective April 12, 1998,
      the Revolving Credit Period under the Credit Agreement dated as of
      June 12, 1996 among Oceaneering International, Inc. (the "Borrower"),
      the Banks parties thereto and Xxxxxx Guaranty Trust Company of New York,
      as agent (the  "Credit Agreement") for one year to April 12, 1999.
      Terms defined in the Credit Agreement are used herein as therein defined. 

         This Extension Agreement shall be construed in accordance
      with and governed by the law of the State of New York. 


                                           XXXXXX GUARANTY TRUST COMPANY
                                             OF NEW YORK
                                           By //Xxxxxxx Xxxxx-Xxxxx//
                                              Title: Vice President

                                           ABN AMRO BANK N.V.
                                           By //X. Xxxxxxxx/S Balette//
                                              Title: SVP/AVP

                                           CHASE BANK OF TEXAS, N.A.
                                           By //Xxxx X. Xxxx//
                                              Title:

                                           XXXXX FARGO BANK (TEXAS), NA
                                           By //Xxxxx X. Xxxxxxxxx//
                                              Title: Vice President

             Agreed and accepted:

             OCEANEERING INTERNATIONAL, INC. 
             By //Xxxxxx X. Xxxxxxx//
                Title: Treasurer

             XXXXXX GUARANTY TRUST COMPANY
               OF NEW YORK, as Agent
             By //Xxxxxxx Xxxxx-Xxxxx//
                Title: Vice President