FIRST SUPPLEMENTAL INDENTURE

Exhibit 4.18

XXXXXXXX OFFSHORE SERVICES, INC. and
the Guarantors named herein 1.500% Convertible Senior Notes due 2019
FIRST SUPPLEMENTAL INDENTURE
Dated as of October 6, 2015

XXXXX FARGO BANK, NATIONAL ASSOCIATION
Trustee

FIRST SUPPLEMENTAL INDENTURE

THIS FIRST SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of October 6, 2015, among Xxxxxxxx Offshore International, LLC (the “Guaranteeing Subsidiary”), a subsidiary of Xxxxxxxx Offshore Services, Inc. (or its permitted successor), a Delaware corporation (the “Company”), the Company, the other Guarantors (as defined in the Indenture referred to herein) and Xxxxx Fargo Bank, National Association, as trustee under the Indenture referred to below (the “Trustee”).

WITNESSETH

WHEREAS, the Company has heretofore executed and delivered to the Trustee an Indenture, dated as of August 13, 2012 (the “Indenture”), providing for the issuance of 1.500% Convertible Senior Notes due 2019 (the “Securities”);

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally guarantee all of the Company’s Obligations under the Securities and the Indenture on the terms and conditions set forth herein (the “Subsidiary Guarantee”); and

WHEREAS, pursuant to Section 3.09 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Securities as follows:

1. Capitalized Terms. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2. Agreement to Guarantee. The Guaranteeing Subsidiary hereby agrees to provide an unconditional Guarantee on the terms and subject to the conditions set forth in the Subsidiary Guarantee and in the Indenture including but not limited to Article 13 thereof.

3. No Recourse Against Others. No past, present or future director, officer, employee, incorporator, stockholder or agent of the Guaranteeing Subsidiary (other than the Company or a Guarantor in its capacity as a stockholder of a Subsidiary), as such, shall have any liability for any obligations of the Company or any Guaranteeing Subsidiary under the Securities, any Subsidiary Guarantees, the Indenture or this Supplemental Indenture or for any claim based on, in respect of or by reason of, such obligations or their creation. Each Holder of the Securities by accepting a Security waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Securities. Such waiver may not be

effective to waive liabilities under the federal securities laws and it is the view of the SEC that such a waiver is against public policy.

4. New York Law to Govern. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE.

5. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

6. Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction hereof.

7. The Trustee. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiary and the Company.

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

XXXXXXXX OFFSHORE SERVICES, INC.
By:	/s/ Xxxxx X. Xxxx, Xx.
	Name: Xxxxx X. Xxxx, Xx.
	Title: Executive Vice President and Chief Financial Officer

GUARANTORS:
ENERGY SERVICES PUERTO RICO, LLC
XXXXXXXX OFFSHORE SERVICES, LLC
XXXXXXXX OFFSHORE TRANSPORTATION, LLC
XXXXXXXX OFFSHORE OPERATORS, LLC
HOS-IV, LLC
XXXXXXXX OFFSHORE TRINIDAD & TOBAGO, LLC
HOS PORT, LLC
XXXXXXXX OFFSHORE INTERNATIONAL, LLC
By:	/s/ Xxxxx X. Xxxx, Xx.
	Name: Xxxxx X. Xxxx, Xx.
	Title: Executive Vice President and Chief Financial Officer
XXXXX FARGO BANK, NATIONAL ASSOCIATION,
as Trustee
By:	/s/ Xxxx Xxxxxxxx
	Name: Xxxx Xxxxxxxx
	Title: Vice President