There can be no bigger job than replacing both engines in a motor boat. When we bought our 1938 Silver Class twin-screw diesel yacht, Silver Bird in May 2023, she was on her second set of engines, a pair of 1960 BMC Commodores. The engines had a capacity of somewhere between 3.4 and 3.8 litres, and claimed to produce 60hp at 2,000rpm, to give close to her hull speed of 8.3 knots. So much for the theory! In practice, the engines felt stressed at over 1,800rpm but cruised happily at 1,750, giving somewhere between 6 and 7 knots. At 80dB(A), the main problem was noise but on the plus side, they gave no problems, so long as you turned a blind eye to mild incontinence and a messy bilge.
ENGINE…