A welded aluminium hull is more durable and easier to repair and modify for different applications than a hull constructed from polyester.
Aluminium is the preferred material of various governments for ships from 6 to 20 metre in length. It is often used for small to medium-sized “fisheries” ships in the north-west of America and Canada and in most tenders used by the authorities in the Gulf of Mexico. Aluminium has long been accepted as “the material” for sailing and motor yachts.
Aluminium has a better strength/weight ratio than most shipbuilding materials and is exceptionally dimensionally stable. Aluminium ships weigh 30% to 40% less than comparable polyester ships and 45% to 55% less than comparable steel ships. Lightweight structures have a number of significant advantages, being able to achieve higher speeds and use less fuel with the same propulsion power for given dimensions and shape. They also have a greater shipping capacity so that they can carry larger cargoes. The use of a lighter material results in a ship with a shallower draught.
Durability and reparability
Aluminium is very strong and withstands violent distortion, only bending under forces that will fracture steel or polyester. Aluminium is similar to steel in that it deforms easily, or in other words: it can withstand permanent deformation without rupture. In the event of a collision, aluminium absorbs the energy released over a larger surface area than steel. Polyester, on the other hand, is very fragile and is more likely to crack and break under the same conditions.
Aluminium ships are simpler to repair than polyester ships, particularly if the latter have foam-filled spaces. Dents in aluminium can usually be beaten out fairly easily using a hammer and, if necessary, a damaged piece can be sawn out and replaced without too much difficulty.
Aluminium is not combustible. Polyester, on the other hand, consists partly of mineral oil-based resins, which means that it is combustible. The use of fire-retardant resins in polyester makes it more difficult to ignite, but once it burns, it burns energetically.
Easy to modify
Because, unlike polyester ships, aluminium ships are not formed in a mould, modifications are easy to carry out. Components such as pilot houses, decks, tanks and air chambers can be moved and modified comparatively simply and at low costs.
The aluminium we use, AlMg 4.5 Mn is highly resistant to corrosion. Ships without any corrosion protection that are more than five years old show few, if any, signs of corrosion when used in a marine environment.