Float

push it under; feel it push back.

reshape steel until it floats — buoyancy, felt

The steel's weight never changes — only its shape does, and shape alone decides whether it sinks or floats. Buoyant force equals the weight of water shoved aside, so spreading the same mass into a wider, hollower hull displaces more water, until eventually there is enough of it to hold the steel up.

Concepts: buoyancy.

An interactive you play with one thumb, on Wundr.