Exhibit 4.1

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                           SEABULK INTERNATIONAL, INC.
                              SEACOR HOLDINGS INC.
                                       and
                           the Guarantors named herein

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                          9 1/2% SENIOR NOTES DUE 2013

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                               THIRD SUPPLEMENTAL
                             INDENTURE AND AMENDMENT
                          DATED AS OF FEBRUARY 28, 2006

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                         U.S. BANK NATIONAL ASSOCIATION
                                     Trustee

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           This THIRD SUPPLEMENTAL INDENTURE, dated as of February 28, 2006, is
among Seabulk International, Inc., a Delaware corporation (the "Company"),
SEACOR Holdings Inc. (the "Parent"), each of the parties identified under the
caption "Subsidiary Guarantors" on the signature page hereto (the "Subsidiary
Guarantors") and U.S. Bank National Association, successor to Wachovia Bank,
National Association, as Trustee (the "Trustee").

                                    RECITALS

           WHEREAS, the Company, the initial guarantors party thereto and the
Trustee entered into an Indenture, dated as of August 5, 2003 (the "Indenture"),
pursuant to which the Company has issued $150,000,000 in principal amount of 9
1/2% Senior Notes due 2013 (the "Notes"), of which $138,500,00 aggregate
principal amount are outstanding on the date hereof;

           WHEREAS, the Company is a wholly-owned subsidiary of the Parent;

           WHEREAS, the Company desires to execute and deliver this Third
Supplemental Indenture to, among other things: (i) amend the Indenture to
provide that the reports and other information required to be provided by the
Company may instead be provided by and with respect to the Parent if the Parent
has guaranteed the payment obligations of the Company under the Notes and the
Indenture; (ii) amend the Indenture to permit certain transactions between the
Company and the Parent and the other Subsidiaries of the Parent; and (iii) add
or modify certain defined terms and related text in the Indenture (collectively,
the "Proposed Amendments");

           WHEREAS, the Board of Directors of the Company has determined that it
is in the best interests of the Company to make the Proposed Amendments;

           WHEREAS, the Board of Directors of the Parent has determined that it
is in the best interests of the Parent to fully and unconditionally guarantee
all of the Company's payment obligations under the Notes and the Indenture;

           WHEREAS, Section 9.02 of the Indenture provides that the Company, the
Subsidiary Guarantors and the Trustee may amend the Indenture with the written
consent of the Holders of at least a majority in aggregate principal amount of
the Notes then outstanding;

           WHEREAS the Holders of at least a majority in aggregate principal
amount of the Notes outstanding have consented to the amendments effected by
this Third Supplemental Indenture; and

           WHEREAS, all acts and things prescribed by the Indenture, by law and
by the Certificate of Incorporation and the Bylaws (or comparable constituent
documents) of the Company, of the Parent, of the Subsidiary Guarantors and of
the Trustee necessary to make this Third Supplemental Indenture a valid
instrument legally binding on the Company, the Parent, the Subsidiary Guarantors
and the Trustee, in accordance with its terms, have been duly done and
performed;

           NOW, THEREFORE, to comply with the provisions of the Indenture and in
consideration of the above premises, the Company, the Parent, the Subsidiary
Guarantors and the Trustee covenant and agree for the equal and proportionate
benefit of the respective Holders of the Notes as follows:


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                                    ARTICLE 1

           1.01. This Third Supplemental Indenture is supplemental to the
Indenture and does and shall be deemed to form a part of, and shall be construed
in connection with and as part of, the Indenture for any and all purposes.

                                    ARTICLE 2

           2.01. The definition of "Guarantor" set forth in Section 1.01 of the
Indenture is amended by: (A) deleting "and" from the end of subsection (b)
thereto and inserting "," in lieu thereof; (B) deleting "." from the end of
subsection (c) thereto and inserting "and" in lieu thereof; and (C) adding a
subsection (d) thereto, which shall read as follows: "and for the purposes of
Article 10 only, any direct or indirect parent of the Company that executes a
supplement to this Indenture to fully and unconditionally guarantee the
Company's Obligations under the Notes in accordance with the terms of Article 10
hereof."

           2.02 The definition of "Permitted Investment" set forth in Section
1.01 of the Indenture is amended by: (A) deleting "and" from the end of
subsection (7) thereto; (B) deleting "." from the end of subsection (8) thereto
and inserting "; and" in lieu thereof; and (C) adding a subsection (9) thereto,
which shall read as follows: "loans and advances made to the Parent or any
direct or indirect Subsidiary of the Parent (other than the Company and its
Restricted Subsidiaries)."

           2.03. Section 1.01 of the Indenture is amended to include the
following definition in its proper alphabetical location:

           "Parent" means SEACOR Holdings Inc., a Delaware corporation, or any
other direct or indirect parent company of the Company.

           2.04. Section 4.03 of the Indenture is amended by: (A) restating
subsection (b) in its entirety to read as follows: "Notwithstanding the
foregoing, if the Parent executes and delivers a full and unconditional
guarantee of the Notes, the reports and other information required by this
Section 4.03 may be filed by and be those of the Parent." and (B) deleting
subsection (c) in its entirety.

           2.05. Section 4.09 of the Indenture is amended by: (A) inserting
"(i)" after the first "Indebtedness" in subsection (6) thereto and (B) deleting
", provided" after the first "Restricted Subsidiaries" in subsection (6) thereto
and inserting "or (ii) by the Company and any of its Restricted Subsidiaries
from the Parent and any of its Subsidiaries (other than the Company and its
Restricted Subsidiaries), provided, in each such case," in lieu thereof.

           2.06. Section 4.11 of the Indenture is amended by: (A) deleting "and"
from the end of subsection (2)(b)(G) thereto; (B) deleting "." from subsection
(2)(b)(H) thereto; (C) adding a new subsection (2)(b)(I), which shall read as
follows: "transactions between or among the Company and its Restricted
Subsidiaries, on the one hand, and the Parent and any direct or indirect
Subsidiary of the Parent (other than the Company and its Restricted
Subsidiaries) on the other hand, so long as such transaction is on terms that
are no less favorable to the Company or relevant Restricted Subsidiary than


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those that would have been obtained in a comparable transaction by the Company
or such Restricted Subsidiary in arm's length dealings with an unrelated Person
or, if there is no such comparable transaction, on terms that are fair and
reasonable to the Company or such Restricted Subsidiary; and"; and (D) adding a
new subsection (2)(b)(J), which shall read as follows: "the incurrence of any
Indebtedness permitted under Section 4.09."


                                    ARTICLE 3

           3.01. The Parent hereby fully and unconditionally guarantees on the
terms and subject to the conditions set forth in Article 10 of the Indenture (as
the same applies to the Subsidiary Guarantees), jointly and severally with the
Subsidiary Guarantors, to each Holder and to the Trustee and its successors and
assigns the full and punctual payment of principal of and interest on the Notes
when due, whether at maturity, by acceleration, by redemption or otherwise, and
all other monetary obligations of the Company under the Indenture and the Notes
and the full and punctual performance within all applicable grace periods of all
other obligations of the Company under the Indenture and the Notes.

                                    ARTICLE 4

           4.01. The provisions of this Third Supplemental Indenture became
effective upon its execution; provided, that the amendments to the Indenture set
forth in Article 2 of this Third Supplemental Indenture shall become operative
on the date (the "Payment Date") on which the Company pays the consent fee for
valid consents delivered pursuant to the Consent Solicitation Statement and
Prospectus and accompanying Consent Form, dated as of February 14, 2006, and any
amendments, modifications or supplements thereto. Prior to the Payment Date, the
Company may terminate this Third Supplemental Indenture upon written notice to
the Trustee (it being understood that the Company may, subsequent thereto, enter
into a substitute supplemental indenture).

                                    ARTICLE 5

           5.01. Except as specifically modified herein, the Indenture and the
Notes are in all respects ratified and confirmed (mutatis mutandis) and shall
remain in full force and effect in accordance with their terms with all
capitalized terms used herein without definition having the same respective
meanings ascribed to them as in the Indenture.

           5.02. Except as otherwise expressly provided herein, no duties,
responsibilities or liabilities are assumed, or shall be construed to be
assumed, by the Trustee by reason of this Third Supplemental Indenture. This
Third Supplemental Indenture is executed and accepted by the Trustee subject to
all the terms and conditions set forth in the Indenture with the same force and
effect as if those terms and conditions were repeated at length herein and made
applicable to the Trustee with respect hereto.

           5.03. THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED
IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

           5.04. The parties may sign any number of copies of this Third
Supplemental Indenture. Each signed copy shall be an original, but all of such
executed copies together shall represent the same agreement.


                          [NEXT PAGE IS SIGNATURE PAGE]

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           IN WITNESS WHEREOF, the parties hereto have caused this Third
Supplemental Indenture to be duly executed, all as of the date first written
above.

                                       SEABULK INTERNATIONAL, INC.

                                       By:  /s/ Richard Ryan
                                           -------------------------------------
                                           Name:   Richard Ryan
                                           Title:  Senior Vice President

                                       SEACOR HOLDINGS INC.

                                       By: /s/ Richard Ryan
                                           -------------------------------------
                                           Name:  Richard Ryan
                                           Title: Senior Vice President

                                       SUBSIDIARY GUARANTORS
                                       LONE STAR MARINE SERVICES, INC.
                                       SEABULK ARIZONA USA, INC.
                                       SEABULK ENERGY CARRIERS, INC.
                                       SEABULK ENERGY TRANSPORT, INC.
                                       SEABULK GLOBAL CARRIERS, INC.
                                       SEABULK GLOBAL TRANSPORT, INC.
                                       SEABULK MARINE INTERNATIONAL, INC.
                                       SEABULK MARINE SERVICES, INC.
                                       SEABULK OCEAN TRANSPORT, INC.
                                       SEABULK OFFSHORE ABU DHABI, INC.
                                       SEABULK OFFSHORE DUBAI, INC.
                                       SEABULK OFFSHORE INTERNATIONAL, INC.
                                       SEABULK OFFSHORE OPERATORS, INC.
                                       SEABULK OPERATORS, INC.
                                       SEABULK OVERSEAS TRANSPORT, INC.
                                       SEABULK PETROLEUM TRANSPORT, INC.
                                       SEABULK TANKERS, INC.
                                       SEABULK TOWING, INC.
                                       SEABULK TOWING SERVICES, INC.
                                       SEABULK TRANSMARINE II, INC.
                                       SEABULK TRANSPORT, INC.

                                       By: /s/ Richard Ryan
                                           -------------------------------------
                                           Name:   Richard Ryan
                                           Title:  Vice President


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                                   SEABULK TANKERS, LTD.

                                   By:  SEABULK TRANSPORT, INC.,
                                          General Partner

                                   By:  /s/ Richard Ryan
                                       -----------------------------------------
                                       Name:   Richard Ryan
                                       Title:  Vice President

                                   SEABULK AMERICA PARTNERSHIP, LTD.
                                   SEABULK OFFSHORE, LTD.
                                   SEABULK TRANSMARINE PARTNERSHIP, LTD.

                                   By:  SEABULK TANKERS, LTD.,
                                          General Partner
                                   By:  SEABULK TRANSPORT, INC.,
                                          General Partner

                                   By:  /s/ Richard Ryan
                                       -----------------------------------------
                                        Name:   Richard Ryan
                                        Title:  Vice President

                                   U.S. BANK NATIONAL ASSOCIATION, as TRUSTEE

                                   By:  /s/ John H. Speichert
                                       -----------------------------------------
                                       Name:   John H. Speichert
                                       Title:  Authorized Signature


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