Buoyancy and gravity

[TheOldDog]

TL;DR

What are the effects of varying gravity on buoyancy?
Does the draft of a boat change with gravity?

Fairly simple - I think - but I may have missed something; HS physics was decades ago.

If a boat in a body of water on Earth has a draft of 1m, will the draft of the boat in a similar body of water on, say, Mars have the same draft? (Assume the same temperature of water.) I figured the change in water density would be minimal on the surface, even if it's an ocean we're considering.

This originally came up while reading a SciFi book where the 'artificial' gravity was changing but it got me thinking. After reviewing basic buoyancy I don't recall where gravity really played a role. Buoyancy is dependent on the mass of displacement and the mass of the object, right? I don't see where gravity enters into it - assuming there is *some* gravity (not 'weightless').

Any thoughts? Please let me know ...

 

[haruspex]

TL;DR: What are the effects of varying gravity on buoyancy?
Does the draft of a boat change with gravity?

Buoyancy is dependent on the mass of displacement and the mass of the object, right?

Archimedes' principle is usually expressed in terms of force and weight, not mass, but since the weight of the vessel and weight of the fluid displaced are both proportional gravity…

 

[Demystifier]

The pressure of the water is $p = \rho g h$, so gravity enters through the $g$. But the force of the water $pA$ (where $A$ is the area) acting upwards has to be balanced by the gravitational force $mg$ acting downwards, so the $g$'s cancel, i.e. the draft does not depend on gravity.