Had a sail at my local lake at Wicksteed Park today, between the rain showers, with my RAF Armoured Target Boat.
Its a very strange vessel that only the RAF could have had the idea for. The principle was simple... if you wanted to bomb a boat for real you needed a boat to practice against, but instead of towing a target behind the boat, the boat was the target!
The steering position and engine rooms were armoured with steel plating so the bombs could 'bounce' harmlessly off!
But I hear you say, what about the rest of the boat? It was just a wooden deck with a wooden hull underneath so the even the practice 9lb bombs would rip their way through!
We met an elderly gentleman who actually worked on them and he told us that they carried on board various shaped bits of wood to wedge/jam into the hull and deck where the bombs 'had missed' the armoured structure.
As you can imagine the idea was dropped after a few years of use and switched to towed targets instead.