Wiil ships float lower or higher in tropical waters? Thanks

It won't make much difference. The density of surface sea water varies by at most 1% throughout the oceans. In the tropics, surface temperatures are higher but salinity levels are also usually higher, and the two effects (upon density) tend to cancel out. The density will depend more upon local surface temperatures and the proximity to river outlets, such as the Amazon, than upon latitude.

Ships will float higher in denser water.