EXHIBIT 4.1 GREAT LAKES DREDGE & DOCK CORPORATION as Issuer,and ANY GUARANTORS PARTY HERETO,as Guarantors$325,000,0008.000% Senior Notes due 2022 INDENTURE Dated as of May 24, 2017 Wells Fargo Bank, National Association,as Trustee CROSS-REFERENCE TABLE TIA Section Reference Indenture Section (a) (1) (a) (2) (a) (3) N.A. (a) (4) N.A. (a) (5) (b) 7.08, 7.10 (a) (b) (a) (b) (c) (a) (b) (1) N.A. (b) (2) 7.06, 7.07 (c) 7.06, 12.02 (d) (a) 4.03, 4.04, 12.02 (b) N.A. (c) (1) (c) (2) N.A. (c) (3) N.A. (d) N.A. (e) (a) (b) 7.05, 12.02 (c) (d) (e) (a) (last sentence) (a) (1) (A) (a) (1) (B) (a) (2) N.A. (b) (c) (a) (1) (a) (2) (b) (a) N.A. means Not Applicable.