Quick Question About Heat the Volume of Water

[Ontophile]

Two questions

1) Say you had a small boat with no motor or paddles; no propulsive device save the one I'm about to describe: mounted on the boat's outer hull and submerged in the water, there is a water-heating-mechanism at the bow and a water-cooling-mechanism at the stern. Since heat makes water contract and the absence of heat makes water expand, would these heating- and cooling-mechanics propel the ship forward?

 

[Geezer]

Two questions

1) Say you had a small boat with no motor or paddles; no propulsive device save the one I'm about to describe: mounted on the boat's outer hull and submerged in the water, there is a water-heating-mechanism at the bow and a water-cooling-mechanism at the stern. Since heat makes water contract and the absence of heat makes water expand, would these heating- and cooling-mechanics propel the ship forward?

Liquid water does expand and contract at room temperature, but not by much.

My observation:

The cooling system on the boat is going to produce more waste heat than it removes from the water; if that waste heat is "dumped" back into the water near the stern, then the area around the stern is actually going to WARM up, not cool off.

 

[Drakkith]

Also remember that the change in water temperature is going to cause currents going down and up also.