The following table illustrates the Company’s debt portfolio as of March 31, 2013 and December 31, 2012:

9.125% Senior Notes, due April 2018

On March 22, 2010, we issued $300.0 million aggregate principal amount of 9.125% Senior Notes (9.125% Notes) pursuant to an Indenture between the Company and The Bank of New York Mellon Trust Company, N.A., as trustee. Net proceeds from the 9.125% Notes offering were primarily used to redeem the $225.0 million aggregate principal amount of our 9.625% Senior Notes due 2013 and to repay $42.0 million of borrowings under our senior secured revolving credit facility (Revolver).

On April 25, 2012, we issued an additional $125.0 million aggregate principal amount of 9.125% Notes under the same indenture at a price of 104.0% of par, resulting in gross proceeds of $130.0 million. Net proceeds from the offering were utilized to refinance $125.0 million aggregate principal amount of the 2.125% Convertible Senior Notes due July 2012 (2.125% Notes). We repurchased $122.9 million aggregate principal amount of the 2.125% Notes tendered pursuant to a tender offer on May 9, 2012 and paid off the remaining $2.1 million at their stated maturity on July 15, 2012.

The 9.125% Notes are general unsecured obligations of the Company and rank equal in right of payment with all of our existing and future senior unsecured indebtedness. The 9.125% Notes are jointly and severally guaranteed by substantially all of our direct and indirect domestic subsidiaries other than immaterial subsidiaries and subsidiaries generating revenues primarily outside the United States. Interest on the 9.125% Notes is payable on April 1 and October 1 of each year. Debt issuance costs related to the 9.125% Notes of approximately $11.6 million ($7.2 million, net of amortization) are being amortized over the term of the notes using the effective interest rate method.

At any time prior to April 1, 2013, we may redeem up to 35 percent of the aggregate principal amount of the 9.125% Notes at a redemption price of 109.125 percent of the principal amount, plus accrued and unpaid interest to the redemption date, with the net cash proceeds of certain equity offerings by us. On and after April 1, 2014, we may redeem all or a part of the 9.125% Notes upon appropriate notice, at a redemption price of 104.563 percent of the principal amount, and at redemption prices decreasing each year thereafter to par beginning April 1, 2016. If we experience certain changes in control, we must offer to repurchase the 9.125% Notes at 101.0 percent of the aggregate principal amount, plus accrued and unpaid interest and additional interest, if any, to the date of repurchase.

The Indenture restricts our ability and the ability of certain subsidiaries to: (i) sell assets, (ii) pay dividends or make other distributions on capital stock or redeem or repurchase capital stock or subordinated indebtedness, (iii) make investments, (iv) incur or guarantee additional indebtedness; (v) create or incur liens; (vi) enter into sale and leaseback transactions; (vii) incur dividend or other payment restrictions affecting subsidiaries, (viii) merge or consolidate with other entities, (ix) enter into transactions with affiliates, and (x) engage in certain business activities. Additionally, the Indenture contains certain restrictive covenants designating certain events as Events of Default. These covenants are subject to a number of important exceptions and qualifications.

Amended and Restated Credit Agreement

On December 14, 2012, we entered into an Amended and Restated Credit Agreement (Credit Agreement) consisting of a senior secured $80.0 million Revolver and senior secured term loan facility (Term Loan) of $50.0 million. The Credit Agreement amended and restated our existing credit agreement dated May 15, 2008 (Existing Credit Agreement). The Credit Agreement provides that, subject to certain conditions, including the approval of the Administrative Agent and the lenders’ acceptance (or additional lenders being joined as new lenders), the amount of the Term Loan or Revolver can be increased by an additional $50.0 million, so long as after giving effect to such increase, the aggregate commitments are not be in excess of $180.0 million.

Our obligations under the Credit Agreement are guaranteed by substantially all of our domestic subsidiaries, each of which have executed guaranty agreements; and are secured by first priority liens on our accounts receivable, specified barge rigs and rental equipment. The Credit Agreement contains customary affirmative and negative covenants with which we were in compliance as of March 31, 2013 and December 31, 2012. The Credit Agreement matures on December 14, 2017.

Revolver

Our Revolver is available for general corporate purposes and to support letters of credit. Interest on Revolver loans accrues at a Base Rate plus an Applicable Rate or LIBOR plus an Applicable Rate. Under the Credit Agreement, the Applicable Rate varies from a rate per annum ranging from 2.50 percent to 3.00 percent for LIBOR rate loans and 1.50 percent to 2.00 percent for base rate loans, determined by reference to the consolidated leverage ratio (as defined in the Credit Agreement). Revolving loans are available subject to a borrowing base calculation based on a percentage of eligible accounts receivable, certain specified barge drilling rigs and rental equipment of the Company and its subsidiary guarantors. There were no revolving loans outstanding at March 31, 2013 and December 31, 2012. Letters of credit outstanding as of March 31, 2013 and December 31, 2012 totaled $2.8 million and $4.5 million, respectively.

Term Loan

The Term Loan originated at $50.0 million on December 14, 2012 and requires quarterly principal payments of $2.5 million, which began March 31, 2013. Interest on the Term Loan accrues at a Base Rate plus 2.00 percent or LIBOR plus 3.00 percent. The outstanding balance on the Term Loan at March 31, 2013 and December 31, 2012 was $47.5 million and $50.0 million, respectively