Ah, boat detailing in Florida in the summer.
It's my least favorite form of detailing and I charge extra because of it. I am pretty selective about the boats I do and I always look at them before I give a price.
Most guys charge by the linear foot with boats and that works for the smaller boats that are used for fishing or skiing. When you get boats with cabins or bathrooms, the linear foot pricing doesn't really work IMO.
I just estimate time. Decide how much you want to make per hour and multiply it by the hours it will take you. That will be tough for you since you are new to boat detailing, you won't have a good idea of how long it will take you. All I can say is it will take you longer than you think.
Here is an example;
I am doing a 22' open fisher next week and it has no oxidized surfaces and it is on a trailer. To do it from top to bottom including compartments it will take me roughly 5 hours.
I charge $80 per hour for boats so it will be $400.00.