Duralumin is an aluminium-copper alloy widely used in aviation. An early alloy containing 4% copper hardened after quenching when left at room temperature for several days. Its use in Soviet torpedo boats is linked to aircraft designer Andrei Tupolev and a preference for aluminium construction. A captured Soviet officer, possibly a boat commander, reportedly described haul-outs for cleaning and corrosion treatment every five to seven days in summer and roughly ten to fifteen days in winter. Sacrificial zinc anodes were already a known form of protection, yet these boats lacked them. Mooring an alloy boat beside a steel cruiser could make the smaller hull behave like a sacrificial anode for the larger ship. The frequent maintenance reduced the time a fast boat could remain available for operations.
Notable Point · 2:05:41-2:15:33
How an aviation alloy became a naval maintenance burden
Duralumin gave Soviet fast boats a light structure, but aircraft-derived design choices imposed relentless corrosion control in salt water.