The first partially aluminum cutter Le Migron was built in Switzerland in 1891. Several years later a 58-metre torpedo boat was built from aluminum in Scotland. It was very sturdy and achieved a speed of 32 knots, which was unheard of at the time. The boat was called the Hawk and was built for the Russian navy.
Modern seafaring vessels are increasingly being built from so-called marine aluminum, an umbrella term that refers to a broad range of aluminum-magnesium alloys (magnesium content varies between 3 and 6%) used in mechanical engineering. These alloys have outstanding corrosion resistance in both fresh- and seawater.
Important properties of marine aluminum include strength and ease of welding. Aluminum sheets and slabs for ship building are made using cold or hot rolling while extrusions, rods and pipes can be made using rolling, pulling or pressing.
Duralumin or magnalium are also used for building high-speed hydrofoil passenger boats that travel at speeds in excess of 80 kph. To ensure high speed and manoeuvrability, these boats need to be very light, thus aluminum comes to the rescue again.
Marine aluminum is 100 times less prone to corrosion than steel. In the first year of operation steel gets covered in corrosion at a rate of 120 mm per year, while aluminum at a rate of only 1 mm per year. In addition, marine aluminum has outstanding strength. It’s flexible, and even a powerful blow can’t punch a hole in the body of a welded-aluminum boat. Aluminum frames improve seaworthiness, deliver better security and reduce maintenance costs.
It is for this reason that aluminum is used in yachts, motor boats, cutters as well as underwater craft. As a rule, sporting boats are built from aluminum from keel to mast, which gives them a speed advantage, while high capacity vessels are built from steel while the superstructure and other auxiliary equipment is made from aluminum to save weight and increase the cargo carrying capacity.
Reprint From UC RUSAL