Boats made of aluminium clearly has the longest life span of the two. A very high material strength, good corrosion resistance, and other advantages of aluminum makes it possible for an aluminum boat to easily live 30-40 years. This longevity also results in a low impairment and a high resale value.
GRP material is extremely brittle and is thus subject to cracking and fracture during high impacts while aluminium has considerable ductility, i.e., the ability to withstand permanent deformation without rupture. This is because aluminium has low modulus of elasticity, it absorbs the energy of the impact and prevents damages.
Aluminium boats are 30% to 40% lighter than fiberglass boats and 45% to 55% lighter than steel boats. This weight saving provides many advantages, including lower fuel consumption, higher speeds and greater payload. Less weight also makes it easier to transport and handle the boat ashore.
Aluminium is not affected by ultraviolet rays from the sun, which can damage the fiberglass boat gelcoat, the hull and underlying structure. This will make fiberglass boats fragile over time.
Aluminium does not burn. GRP boats contain petroleum based resins which burn energetically. Fire retardant resin makes them harder to “light”, but nonetheless the burning is energetic once started.
Aluminium is 100% recyclable making it a more environmentally friendly material to use than fiberglass. Recovering fiberglass is a longer, more complicated, less efficient (~ 80%) and expensive process, which makes dumping of disused fiberglass boats a problem that the Norwegian Ministry of Environment has raised its concern about.