I've just been discussing this question with my eldest son, who is an extremely intelligent man, as well as being an engineer, a sailor and a scuba-diver, and he believes that an object heavier than water, such as his anchor, or his diving weights actually becomes less heavy when submerged in water. I described a scenario, whereby a solid steel, or lead weight was suspended from a spring balance and slowly lowered into a body of water, the weight reading on the spring balance would not change. He insisted that it would... I think it would not, because an object that is denser than water would not posess any buoyancy once submerged, therefore the density and weight would remain unchanged. Any comments anyone??? There's a £5 bet riding on this :)