GUARANTY

Exhibit 10.15

GUARANTY

given by

GULFMARK OFFSHORE, INC.

in favor of

DVB BANK NV,
as Security Trustee

July 1, 2008

GUARANTY

          THIS GUARANTY (this “Guaranty”), dated as of July 1, 2008, is made by GULFMARK OFFSHORE, INC., a corporation organized and existing under the laws of Delaware (the “Guarantor”), in favor of DVB BANK NV, a bank incorporated under the laws of the Kingdom of the Netherlands (“DVB”), as security trustee (the “Security Trustee”) for and on behalf of the Lenders (as such term is defined herein).

WITNESSETH THAT:

          WHEREAS:

          (A) Pursuant to that certain that Senior Secured Credit Facility Agreement dated as of December 28, 2005, as amended by Amendment No. 1 thereto dated as of February 28, 2006, by Amendment No. 2 thereto dated as of May 9, 2007 and by Amendment No. 3 (“Amendment No. 3”) thereto dated July 1, 2008 (as so amended, the “Facility Agreement”), made by and among, inter alios , (i) Rigdon Marine Corporation, as borrower (the “Borrower”), (ii) the banks and financial institutions listed on Schedule 1 of the Facility Agreement, as lenders (together with any bank or financial institution which becomes a Lender pursuant to Article 10 of the Facility Agreement (the “Lenders”)), and (iii) DVB, as security trustee and as facility agent, the Lenders have agreed to provide the Borrower a loan facility in an aggregate principal amount of up to US$224,000,000 (the “Facility”) in three tranches, Tranche A, Tranche B and Tranche C, for the purposes described in Section 3.1 thereof.

          (B) The Borrower is a wholly owned subsidiary of the Guarantor; and

          (C) It is a condition precedent to the effectiveness of Amendment No. 3 that the Guarantor enter into this Guaranty and otherwise agree to be bound by the terms of this Guaranty.

          NOW, THEREFORE, in consideration of the premises and for other valuable consideration, the receipt and adequacy of which the Guarantor hereby acknowledges, the Guarantor hereby agrees as follows:

          SECTION 1. Defined Terms . Except as otherwise defined herein, terms defined in the Facility Agreement shall have the same meaning when used herein. The words and expressions specified below shall, except where the context otherwise requires, have the meanings attributed to them below:

          (a) “ Compliance Certificate ” means a certificate of the Chief Financial Officer of the Guarantor to be delivered to the Facility Agent substantially in the form attached hereto as Exhibit 1;

          (b) “ Determination Date ” means:

               (i) the last day of each calendar quarter;

               (ii) after the occurrence of an Event of Default which is continuing, any date designated by the Facility Agent upon at least three (3) Banking Days’ prior written notice to the Guarantor; and

               (iii) each Drawdown Date.

          (c) “ EBITDA ” means, for any twelve month period ending on a Determination Date, the consolidated profit on ordinary activities of the Group before Taxes:

               (i) adjusted to exclude interest received or receivable and other similar income to the extent not already excluded;

               (ii) before the depreciation of fixed assets but after excluding any loss or gain arising on the disposal of fixed assets or shares;

               (iii) before the deduction of Interest Expense for such period;

               (iv) before any charge for the amortization of goodwill, merger differences, acquisition costs or any other intangible asset; and

               (v) before adding or deducting extraordinary or exceptional items (to include, for the avoidance of doubt, any redundancy costs and foreign exchange profits and losses in relation to the funding of the business) in each case for such period;

          (d) “ Group ” means the Guarantor and each of its Subsidiaries;

          (e) “ Interest Expense ” means the interest paid by any member of the Group on the Total Debt in the twelve month period ending on a Determination Date;

          (f) “ Taxes ” means all taxes (including, without limitation, property, sales, use, consumption, franchise, capital, occupational, license, value added, excise, stamp, levies and imposts taxes and customs and other duties), assessments, fees (including, without limitation, documentation, license, filing and registration fees) and charges, of any kind or nature whatsoever, together with any penalties, fines, additions to tax or interest thereon, however imposed, withheld, levied, or assessed by any country or governmental subdivision thereof or therein, any international authority or any other taxing authority other than taxes on the overall net income of a Creditor or branch thereof;

          (g) “ Total Assets ” means the amount which is equal to the total consolidated assets of the Guarantor as shown in the Guarantor’s latest audited consolidated balance sheet less the goodwill (if any) of the Guarantor as shown in the Guarantor’s latest audited balance sheet;

          (h) “ Total Debt ” means the aggregate of:

               (i) the amount calculated in accordance with GAAP shown as each of “long term debt”, “short term debt” and “current portion of long term debt” on the latest consolidated balance sheet of the Guarantor; and

               (ii) the amount of any liability in respect of any lease or hire purchase contract entered into by the Guarantor or any of its Subsidiaries which would, in accordance with GAAP, be treated as a finance or capital lease; and

          (i) “ Total Shareholder Equity ” means the aggregate of the amount paid up on the issued share capital of the Guarantor and the amount standing to the credit of its capital and revenue reserves (including any share premium account or capital redemption reserve but excluding any revaluation reserve) plus or minus the amount standing to the credit or debit (as the case may be) of its profit and loss account.

          SECTION 2. Guaranty .

          2.1 Guaranty of Payment and Performance . The Guarantor, as primary obligor and not merely as surety, hereby irrevocably, unconditionally and absolutely guarantees to the Security Trustee, for the benefit of the Creditors, on first demand (a) the full and prompt payment, when due, whether by acceleration or otherwise, of all amounts owing by the Borrower to the Creditors under the Facility Agreement, the Note and the Security Documents (collectively, the “Transaction Documents”), together with any costs and expenses (including, without limitation, attorneys’ fees) incurred in connection therewith by the Creditors and the performance by the Borrower of its obligations and, in case of extension of time of payment or renewal in whole or in part of the said obligations of the Borrower, the prompt payment when due of all said amounts according to such extension or extensions or renewal or renewals, whether by acceleration or otherwise and (b) the punctual and full performance and compliance by the Borrower of each and every duty, covenant, agreement and obligation thereof under the Transaction Documents (all obligations referred to in clauses (a) and (b) above are herein referred to as the “Obligations”).

          2.2 Nature of Guaranty . This Guaranty is a guaranty of payment, performance and compliance and not of collection and the Guarantor expressly agrees that it shall not be necessary or required that the Creditors exercise any right, assert any claim or demand or enforce any remedy whatsoever against the Borrower or any other Person before or as a condition to the obligations of the Guarantor hereunder. This Guaranty is a primary obligation of the Guarantor and shall be an absolute, unconditional, present, and continuing obligation and shall not be subject to any counterclaim, setoff, deduction, diminution, abatement, recoupment, suspension, deferment, reduction, or defense based on any claim the Guarantor or any other Person may have against the Borrower, the Creditors or any other Person. This Guaranty shall only be discharged by the complete and indefeasible satisfaction of all of the Obligations and shall not be released, discharged or affected by any circumstance whatsoever, including without limitation:

          (a) the unenforceability, invalidity, irregularity or lack of genuineness of the Transaction Document or any of the obligations under the Transaction Documents;

          (b) any amendment, modification, termination, or removal of, or addition or supplement to, the Transaction Documents, or any change in time, manner, or place of payment or performance of any Obligation;

          (c) any assignment, mortgage, release, exchange, addition, or transfer of any Collateral;

          (d) any failure, refusal, omission or delay on the part of the Borrower, any Creditor or any other Person to conform or comply with any term of the Transaction Documents or any other agreement;

          (e) any waiver, consent, extension, indulgence, surrender, settlement, subordination, release, compromise, or other agreement, or the exercise or non-exercise of any right or remedy thereunder, with or without consideration;

          (f) the occurrence and/or continuance of any bankruptcy, insolvency, reorganization, liquidation, arrangement, adjustment of debt, relief of debtors, dissolution, or similar proceeding with respect to the Borrower, any Creditor, or any other Person, including without limitation any modification of the Borrower’s obligations under any Transaction Document in connection with any such proceeding;

          (g) any defect in the title, condition, compliance with specifications, design, operation, or fitness for use of, or any damage to or loss of, or governmental prohibition or restriction, condemnation, requisition, or seizure of, any Collateral for any reason;

          (h) any merger, consolidation, restructuring, termination of existence, sale of assets, or change in the ownership of any membership interests, shares of capital stock or other equity interest of the Borrower or the Guarantor;

          (i) any present or future law, regulation, or order in any jurisdiction (whether of right or in fact) or any agency thereof affecting any term of any Obligation or any rights of any Creditor with respect thereto, including, without limitation, any law, regulation or order purporting to vary the terms of payment or to restrict the right or power of the Borrower or of the Guarantor or either of them to make payment of any of their respective Obligations to the Creditors; or

          (j) any other circumstances whatsoever which might otherwise constitute a defense available to, or a discharge of, either the Borrower or the Guarantor.

          SECTION 3. Representations and Warranties . The Guarantor hereby represents and warrants to the Security Trustee, for the benefit of the Creditors, (which representations and warranties shall survive the execution and delivery of this Guaranty) as follows:

          3.1 Due Organization and Power . The Guarantor is duly formed and is validly existing in good standing under the laws of its jurisdiction of incorporation or formation, has full power to carry on its business as now being conducted and to enter into and perform its obligations under this Guaranty, and has complied with all statutory, regulatory and other requirements relative to such business and such agreements;

          3.2 Authorization and Consents . All necessary corporate action has been taken to authorize, and all necessary consents and authorities have been obtained and remain in full force and effect to permit, the Guarantor to enter into and perform its obligations under this Guaranty;

          3.3 Binding Obligations . This Guaranty constitutes the legal, valid and binding obligations of the Guarantor enforceable against the Guarantor in accordance with its terms, except to the extent that such enforcement may be limited by equitable principles,

principles of public policy or applicable bankruptcy, insolvency, reorganization, moratorium or other laws affecting generally the enforcement of creditors’ rights;

          3.4 No Violation . The execution and delivery of, and the performance of the provisions of, this Guaranty do not contravene any applicable law or regulation existing at the date hereof or any contractual restriction binding on the Guarantor or the certificate of incorporation or by-laws thereof.

          SECTION 4. Covenants .

          4.1 Affirmative Covenants . The Guarantor hereby covenants and undertakes with the Security Trustee, for the benefit of the Creditors, that from the date hereof and so long as any Obligation remains unsatisfied, it shall:

          (a) duly perform and observe the terms of this Guaranty;

          (b) immediately upon obtaining knowledge thereof, inform the Security Trustee of the occurrence of (i) any Event of Default or of any event which, with the giving of notice or lapse of time, or both, would constitute an Event of Default, (ii) any litigation or governmental proceeding pending or threatened against it which could reasonably be expected to have a material adverse effect on its or the Borrower’s business, assets, operations, property or financial condition and (iii) any event or condition which is reasonably likely to have a material adverse effect on its ability to perform its obligations under this Guaranty; and

          (c) obtain every consent and do all other acts and things which may from time to time be necessary or advisable for the continued due performance of all its obligations under this Guaranty.

          4.2 Financial Covenants . The Guarantor hereby covenants and undertakes with the Security Trustee, for the benefit of the Creditors, that from the date hereof and so long as any Obligation remains unsatisfied, it shall:

          (a) maintain a ratio of Total Shareholder Equity to Total Assets of at least thirty-five percent (35%);

          (b) maintain a ratio of EBITDA to Interest Expense of no less than 2.25:1.00; and

          (c) deliver a completed and executed Compliance Certificate to the Facility Agent on such dates as the Borrower is required to deliver its financial statements in accordance with Sections 9.1(d)(i) and 9.1(d)(ii) of the Facility Agreement.

          SECTION 5. Payments .

          5.1 Payment . (a) All payments by the Guarantor under this Guaranty shall be made in the same manner as the Borrower is required to make payments under the Facility Agreement as specifically set forth therein.

          (b) On any amount or amounts for which the Guarantor is liable hereunder interest shall be due at the Default Rate specified in Section 6.2 in the Facility Agreement from

the due date thereof under the Facility Agreement until the date of payment of such amount by the Guarantor or the Borrower.

          5.2 Currency of Account . (a) If for the purpose of obtaining or enforcing a judgment in any court in any country, it becomes necessary to convert into any other currency (the “Judgment Currency”) an amount due in Dollars under this Guaranty then the conversion shall be made, in the discretion of the Security Trustee, at the rate of exchange prevailing either on the date of default or on the day before the day on which the judgment is given or the order for enforcement is made, as the case may be (the “Conversion Date”) provided that the Security Trustee shall not be entitled to recover under this clause any amount in the Judgment Currency which exceeds at the Conversion Date the amount in Dollars due under this Guaranty.

          (b) If there is a change in the rate of exchang