I'm doing an event in the summer that will be on a cruise ship for approx 1500-2500 people. It is going to be out on an open deck. Any thoughts/recs on how to go estimating how much additional sound would be needed compared to a regualr outdoor event. I'm guessing the cross winds will affect the sound.
Who says there are cross winds? Unless you know which way the wind will be blowing-the direction of the ship and the speed-there may be no "wind" at all-that you feel.
When trying to "estimate" sound needed-the number of people is pretty worthless. It is the physical size of the AREA you want to cover-how loud it needs to be (be sure to state A and C weighted and fast or slow response times). Estimated headroom would also be nice to know.
Is this hard techno that you are trying to create an indoor type club sound-or smooth jazz? Those have VERY different sound requirements.
Then you have the whole issue of "where can you put the PA". That may or may not be a big factor.
Do you have unlimited power available? OR is that going to be an issue-such as having to use speakers with higher sensitivities and so forth.
So basically you need to provide a lot more information.