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                                                                    EXHIBIT 4d

                              ROWAN COMPANIES, INC.
                           CERTIFICATE OF DESIGNATIONS
               Providing for an Issue of Series B Preferred Stock
             Pursuant to Section 151 of the General Corporation Law
                            of the State of Delaware



      ROWAN COMPANIES, INC., a Delaware corporation (the "Corporation"),
certifies that, pursuant to the authority contained In Article Fourth of its
Certificate of Incorporation and in accordance with the provisions of Section
151 of the General Corporation Law of the State of Delaware, the 1998 Debenture
Plan Committee of the Board of Directors duly approved at its April 22, 1999
meeting (at which a quorum was present), and the Board of Directors duly
ratified and approved at its April 23, 1999 meeting (at which a quorum was
present), the empowerment of and the issuance of a directive to the proper
officers of the Corporation for the purpose of having such officers take the
appropriate actions which, in their opinion, may be necessary or proper to
create and provide for the issuance of a series of shares of Preferred Stock as
described below, and further providing for the voting powers, designations,
preferences and relative, participating, optional or other rights thereof, and
the qualifications, limitations or restrictions thereof, in addition to those
set forth in said Certificate of Incorporation, all in accordance with the
provisions of Section 151 of the General Corporation Law of the State of
Delaware, and that the approval creating such empowerment and establishing such
directive has at all times since remained in effect and is now in effect and
unamended:

     (1)  Pursuant to Paragraph A of Article Fourth of the Certificate of
          Incorporation of the Corporation, as amended (which creates and
          authorizes 5,000,000 shares of preferred stock, par value of $1.00 per
          share, hereinafter called the "Preferred Stock"), the Board of
          Directors empowered the proper officers to establish and provide for
          the issue of a series of 4,800 shares of Preferred Stock, designated
          as Series B Preferred Stock (the "Series Stock"), which shares shall
          be issuable only upon conversion of the Series B Floating Rate
          Subordinated Convertible Debentures (the "Related Debentures") of the
          Corporation and shall be convertible into shares of common stock,
          $.125 par value, of the Corporation (the "Common Stock"), pursuant to
          the terms and conditions hereinafter set forth.

     (2)  The voting powers, preferences and relative, participating, optional,
          conversion, and other rights of the shares of the Series Stock, and
          the qualifications, limitations or restrictions thereof, in addition
          to those set forth in said Article Fourth, are as follows:

          Section 1. Dividends. The holders of shares of Series Stock shall not
          be entitled to receive cash dividends on such shares.
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          Section 2. Liquidation Preference. (A) Upon the complete liquidation,
          dissolution, or winding-up of the Corporation, whether voluntarily or
          involuntarily, the Series Stock shall be entitled, before any
          distribution is made to the holders of Common Stock and of any other
          capital stock of the Corporation which ranks junior to the Series
          Stock in respect of distributions of assets on liquidation,
          dissolution or winding-up of the Corporation, to be paid $1.00 per
          share, and shall not be entitled to any further payment.

               (B) In case the net assets of the Corporation are insufficient to
               pay all outstanding shares of Series Stock, and any other class
               of stock of the Corporation ranking in parity upon a liquidation,
               dissolution, or winding-up with the Series Stock ("Parity
               Stock"), the liquidation preferences to which all such shares are
               entitled, then the entire net assets of the Corporation shall be
               distributed ratably to all outstanding shares of the Series Stock
               and Parity Stock, if any, in proportion to the total amounts to
               which the holders of all such shares are entitled upon such
               liquidation, dissolution, or winding-up.

               (C) The merger or consolidation of the Corporation into or with
               another corporation or the merger or consolidation of any other
               corporation into or with the Corporation, or the sale, lease or
               conveyance of all or substantially all the assets, property or
               business of the Corporation shall not be deemed to be a
               liquidation, dissolution, or winding-up of the Corporation within
               the meaning of this Section 2.

          Section 3. Certain Restrictions. Without the consent of the holders of
          at least two-thirds of the total number of shares of Series Stock
          outstanding, given in person or by proxy, either in writing or by vote
          at a meeting called for the purpose, the Corporation shall not create
          or authorize any additional shares of Series Stock or amend, alter or
          repeal any of the rights, preferences or powers of the holders of
          Series Stock so as to affect adversely any such rights, preferences or
          powers; provided, however, that without the consent of the holders of
          all outstanding shares of Series Stock, the Corporation shall not
          amend the Series Stock to adversely affect the Conversion Ratio
          thereof.

          Section 4. Conversion. Each share of the Series Stock may be converted
          at any time within thirty days of the issuance thereof, at the option
          of the holder thereof, into shares of Common Stock of the Corporation,
          on the terms and conditions set forth below in this Section 4.

               (A) Subject to the provisions for adjustment hereinafter set
               forth, the number of shares of Common Stock which shall be
               deliverable upon conversion of a share of Series Stock shall not
               exceed the face value of the Related Debenture which was
               converted into such share of Series Stock divided by the mean of
               the high and low sales price of the Company's Common Stock on the
               date of sale of such Related Debenture. For the


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               purpose of this subparagraph (A) of this Section 4, the terms
               "closing price" and "Trading Date" shall have the meanings
               attributed to them in subparagraph (B)(6) of this Section 4.

               (B) The number of shares of Common Stock which shall be
               deliverable upon conversion of a share of Series Stock (the
               "Conversion Ratio") shall be adjusted from time to time as
               follows:

                    (1) In case the Corporation at any time or from time to time
                    following the date of issuance of the Related Debentures
                    which may be converted into shares of Series Stock shall pay
                    or make a dividend or other distribution on any class of
                    capital stock of the Corporation in Common Stock, the
                    Conversion Ratio in effect at the opening of business on the
                    day following the date fixed for the determination of
                    stockholders entitled to receive such dividend or other
                    distribution shall be increased by multiplying such
                    Conversion Ratio by a fraction of which the numerator shall
                    be the sum of the number of shares of Common Stock
                    outstanding at the close of business on the date fixed for
                    such determination and the total number of shares of Common
                    Stock constituting such dividend or other distribution, and
                    the denominator shall be the total number of shares of
                    Common Stock outstanding at the close of business on the
                    date fixed for such determination, such increase to become
                    effective immediately after the opening of business on the
                    day following the date fixed for such determination. For the
                    purposes of this subparagraph (13)(1), the number of shares
                    of Common Stock at any time outstanding shall not include
                    shares held in the treasury of the Corporation but shall
                    include shares issuable in respect of scrip certificates
                    issued in lieu of fractions of shares of Common Stock. The
                    Corporation will not pay any dividend on shares of Common
                    Stock held in the treasury of the Company.

                    (2) In case the Corporation shall issue rights or warrants
                    to all holders of its Common Stock entitling them (for
                    periods ending within 180 days) to subscribe for or purchase
                    shares of Common Stock at a price per share less than the
                    current market price per share (determined as provided in
                    subparagraph (B)(6) of this Section) of the Common Stock on
                    the date fixed for the determination of stockholders
                    entitled to receive such rights or warrants, the Conversion
                    Ratio in effect at the opening of business on the day
                    following the date fixed for such determination shall be
                    increased by multiplying such Conversion Ratio by a fraction
                    of which the numerator shall be the number of shares of
                    Common Stock outstanding at the close of business on the
                    date fixed for such determination plus the number of

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                    shares of Common Stock so offered for subscription or
                    purchase, and the denominator shall be the number of shares
                    of Common Stock outstanding at the close of business on the
                    date fixed for such determination plus the number of shares
                    of Common Stock which the aggregate of the offering price of
                    the total number of shares of Common Stock so offered for
                    subscription or purchase would purchase at such current
                    market price, such increase to become effective immediately
                    after the opening of business on the day following the date
                    fixed for such determination. For the purposes of this
                    subparagraph (B)(2), the number of shares of Common Stock at
                    any time outstanding shall not include shares held in the
                    treasury of the Corporation but shall include shares
                    issuable in respect of scrip certificates issued in lieu of
                    fractions of shares of Common Stock. The Corporation will
                    not issue any rights or warrants in respect of shares of
                    Common Stock held in the treasury of the Corporation.

                    (3) In case outstanding shares of Common Stock shall be
                    subdivided into a greater number of shares of Common Stock,
                    the Conversion Ratio in effect at the opening of business on
                    the day following the day upon which such subdivision
                    becomes effective shall be proportionately increased, and,
                    conversely, in case outstanding shares of Common Stock shall
                    each be combined into a smaller number of shares of Common
                    Stock, the Conversion Ratio in effect at the opening of
                    business on the day following the day upon which such
                    combination becomes effective shall be proportionately
                    decreased, such increase or reduction, as the case may be,
                    to become effective immediately after the opening of
                    business on the day following the day upon which such
                    subdivision or combination becomes effective.

                    (4) In case the Corporation shall, by dividend or otherwise,
                    distribute to all holders of its Common Stock evidences of
                    its indebtedness or assets (including securities, but
                    excluding any rights or warrants referred to in subparagraph
                    (B)(2) of this Section, any dividend or distribution paid in
                    cash out of the earned surplus of the Company and any
                    dividend or distribution referred to in subparagraph (B)(1)
                    of this Section), the Conversion Ratio shall be adjusted so
                    that the same shall equal that number determined by
                    multiplying the Conversion Ratio in effect immediately prior
                    to the close of business on the date fixed for the
                    determination of stockholders entitled to receive such
                    distribution by a fraction of which the numerator shall be
                    the current market price per share (determined as provided
                    In subparagraph (B)(6) of this Section) of the Common Stock
                    on the date fixed for such determination and the denominator
                    shall be such current market price per share of the Common
                    Stock less the then fair market value (as determined by the
                    Board of Directors, whose determination shall be conclusive
                    and described in a resolution of such Board of Directors) of
                    the portion of the assets or evidences of indebtedness so
                    distributed applicable to one share of Common Stock, such
                    adjustment to become effective immediately prior to the
                    opening of business on the day following the



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                    date fixed the determination of stockholders entitled to
                    receive such distribution.

                    (5) The reclassification (including any reclassification
                    upon a consolidation or merger in which the Corporation is
                    the continuing corporation) of Common Stock into securities
                    including other than Common Stock shall be deemed to involve
                    (a) a distribution of such securities other than Common
                    Stock to all holders of Common Stock (and the effective date
                    of such reclassification shall be deemed to be "the date
                    fixed for the determination of stockholders entitled to
                    receive such distribution" and "the date fixed for such
                    determination" within the meaning of subparagraph (B)(4) of
                    this Section), and (b) a subdivision or combination, as the
                    case may be, of the number of shares of Common Stock
                    outstanding immediately prior to such reclassification into
                    the number of shares of Common Stock outstanding immediately
                    thereafter (and the effective date of such reclassification
                    shall be deemed to be "the day upon which such subdivision
                    becomes effective" or "the day upon which such combination
                    becomes effective," as the case may be, and "the day upon
                    which such subdivision or combination becomes effective"
                    within the meaning of subparagraph (B(3) of this Section).

                    (6) For the purpose of any computation under subparagraphs
                    (B)(2) and (B)(4) of this Section, the current market price
                    per share of Common Stock on any date shall be deemed to be
                    the average of the daily closing prices for the 15
                    consecutive "Trading Days" selected by the Company
                    commencing not less than 20 nor more than 30 Trading Days
                    before the day in question, The closing price for each day
                    shall be the last reported sales price regular way or, in
                    case no such reported sale takes place on such day, the
                    average of the reported closing bid and asked prices regular
                    way, in either case on the New York Stock Exchange or, if
                    the Common Stock is not listed or admitted to trading on
                    such Exchange, on the principal national securities exchange
                    on which the Common Stock is listed or admitted to trading
                    or, if not listed or admitted to trading on any national
                    securities exchange, the average of the closing bid and
                    asked prices as furnished by any New York Stock Exchange
                    member firm selected from time to time by the Corporation
                    for that purpose. The term "Trading Date" shall mean a day
                    on which the principal national securities exchange on which
                    shares of the Common Stock are listed or admitted to trading
                    is open for the transaction of business or, if not listed or
                    admitted to trading on any national securities exchange, a
                    Monday, Tuesday, Wednesday, Thursday or Friday on which
                    banking institutions in the City of Houston, Texas are not
                    authorized or obligated by law or executive order to close.

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                    (7) The Corporation may make such increases in the
                    Conversion Ratio, in addition to those required by
                    subparagraphs (B)(1), (B)(2), (B)(3) and (B)(4) of this
                    Section. as it considers to be advisable in order that any
                    event treated for Federal Income tax purposes as a dividend
                    of stock or stock rights shall not be taxable to the
                    recipients.

                    (8) No adjustment in the Conversion Ratio shall be required
                    unless such adjustment would require an increase or decrease
                    of at least one percent in such Conversion Ratio; provided,
                    however, that any adjustment which by reason of this
                    subparagraph (B)(8) is not required to be made shall be
                    carried forward and taken into account in any subsequent
                    adjustment. All calculations under this Article shall be
                    made to the nearest 1/100 of a share.

               (C) The holder of any shares of the Series Stock may exercise his
               option to convert such shares into shares of Common Stock by
               surrendering for such purpose to the Corporation, at its
               principal office or at such other office or agency maintained by
               the Corporation for that purpose, a certificate or certificates
               representing the shares of Series Stock to be converted
               accompanied by a written notice stating that such holder elects
               to convert all or a specified whole number of such shares in
               accordance with the provisions of this Section 4. As promptly as
               practicable, and in any event within five business days after the
               surrender of such certificates and the receipt of such notice
               relating thereto, the Corporation shall deliver or cause to be
               delivered (i) certificates representing the number of validly
               issued, fully paid and nonassessable shares of Common Stock of
               the Corporation to which the holder of the Series Stock so
               converted shall be entitled and (ii) If less than the full number
               of shares of the Series Stock evidenced by the surrendered
               certificate or certificates are being converted, a new
               certificate or certificates, of like tenor, for the number of
               shares evidenced by such surrendered certificate or certificates
               less the number of shares converted. Conversions shall be deemed
               to have been made at the close of business on the date of giving
               of such notice and of such surrender of the certificate or
               certificates representing the shares of the Series Stock to be
               converted so that the rights of the holder shall cease with
               respect to such surrendered certificates except for the right to
               receive Common Stock of the Corporation in accordance herewith,
               and the converting holder shall be treated for all purposes as
               having become the record holder of such Common Stock of the
               Corporation at such time.

               (D) In connection with the conversion of any shares of the Series
               Stock, no fractions of shares or Common Stock shall be issued,
               but the Corporation shall pay a cash adjustment in respect of
               such fractional interest in an amount equal to the market value
               of such fractional interest. In such event, the market value of a
               share of Common Stock of the Corporation shall be the current
               market price per share (as defined in subparagraph (B)(6) of

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               this Section 4) of such shares on the last Trading Date on which
               such shares were traded immediately preceding the date upon which
               such shares of Series Stock are deemed to have been converted.

               (E) The Corporation shall at all times reserve and keep available
               out of its authorized Common Stock the full number of shares of
               Common Stock of the Corporation issuable upon (a) the conversion
               of all outstanding shares of the Series Stock, and (b) the
               conversion or exercise of any other outstanding securities or
               rights convertible or exercisable into Common Stock, including
               outstanding Related Debentures.

          Section 5. Adjustments for Certain Corporate Transactions. In case of
          any consolidation of the Corporation with, or merger of the
          Corporation into, any other corporation (other than a consolidation or
          merger in which the Corporation is the continuing corporation and in
          which no change is made in the outstanding Common Stock), or in case
          of any sale or transfer of all or substantially all of the assets of
          the Corporation, the corporation formed by such consolidation or the
          corporation resulting from such merger or the person which shall have
          acquired such assets, as the case may be, shall make adequate
          provision providing that the holder of each share of Series Stock then
          outstanding shall have the right thereafter to convert such Series
          Stock into the kind and amount of stock or other securities and
          property receivable upon such consolidation, merger, sale or transfer
          by a holder of the number of shares of Common Stock into which such
          Series Stock might have been converted immediately prior to such
          consolidation, merger, sale or transfer. Adequate provision shall also
          be made to provide for adjustments which, for events subsequent to
          such consolidation, merger, sale or transfer, shall be as nearly
          equivalent as may be practicable to the adjustments provided for in
          Section 4. The above provisions of this Section 5 shall similarly
          apply to successive consolidations, mergers, sales or transfers.

          Section 6. Reports Of Adjustments. Whenever the Conversion Ratio is
          adjusted as provided in Sections 4 and 5, the Corporation shall
          promptly compute such adjustment and promptly mail to each registered
          holder of the Series Stock and the Related Debentures a certificate,
          signed by the chief financial officer of the Corporation, setting
          forth the number of shares of Common Stock into which each share of
          the Series Stock is convertible as a result of such adjustment, a
          brief statement of the facts requiring such adjustment and the
          computation thereof and when such adjustment will become effective.

          Section 7. Voting. Except as otherwise provided elsewhere in the
          Certificate of Incorporation of the Corporation or required by law,
          the holders of Series Stock shall have no voting power in the election
          of directors or for any other purposes.

     (3)  Before the Corporation shall issue any shares of the Series Stock,
          a certificate of designations pursuant to Section 151 of the General
          Corporation Law of the State

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          of Delaware shall be made, executed, acknowledged, filed and recorded
          in accordance with the provisions of said Section 151; and the proper
          officers of the Corporation are hereby authorized and directed to do
          all acts and things which may be necessary or proper in their opinion
          to carry into effect the purposes and intent of this and the other
          actions required to be taken to create and provide for the issuance of
          a series of shares of Preferred Stock as described above.

     IN WITNESS WHEREOF, ROWAN COMPANIES, INC. has caused this Certificate to be
duly executed by its Senior Vice President and attested to by its Secretary and
has caused its corporate seal to be affixed hereto, this 24th day of June, 1999.


                                                 ROWAN COMPANIES, INC.

                                                 By:
                                                    ---------------------------
                                                    Senior Vice President
[Corporate Seal]




ATTEST:


----------------------
Secretary




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THE STATE OF TEXAS )
                   )
COUNTY OF HARRIS   )


     Before me, a Notary Public, on this day personally appeared E. E. Thiele,
known to me to be the person and officer whose name is subscribed to the
foregoing instrument and acknowledged to me that the same was the act of Rowan
Companies, Inc., a Delaware corporation, that he has executed the same as the
act of such corporation for the purposes and consideration therein expressed,
and that the facts stated therein are true.

         Given under my hand and seal of office this 24th day of June, 1999.



                                   --------------------
                                                      Notary Public, in and for
                                                      the State of Texas


My Commission Expires:

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