Based on the promising properties of a family of Al-Mg-Li alloys known as Weldalite(R) 050 alloys, a series of experimental variants were fabricated and evaluated. After being cast, extruded into rectangular bars, and heat treated, a series of mechanical tests was performed to select a composition for marine applications. The alloy variant selected as the most promising candidate displays tensile properties of 438 MPa yield strength, 543 MPa ultimate tensile strength, 5% elongation and 79 GPa elastic modulus, with excellent corrosion and stress corrosion cracking resistance at a density of 2.51 gcm(-3).