After testing this machine in his garden pond (specially built for the purpose) Lethbridge dived on a number of wrecks: four English men-of-war, one East Indiaman (both English and Dutch), two Spanish galleons and a number of galleys. He became very wealthy as a result of his salvages. One of his better-known recoveries was on the Dutch Slot ter Hooge, which had sunk off Madeira with over three tons of silver on board.[3]