The description of the process you gave is very good one.
I am trying to imagine doinmg that on a boat... In my house I do not have any space constrains, but once in a while wife complain about the bottles, buckets etc. in the wrong places.
I do not know how expensive is the beer "in the islands" but I dout it would justify getting a bigger boat.
Then there is the problem of water, both for cleaning the vessels, (both bottles and fermenting buckets) and the idea of boiling 5 gallons of worth on the boat stove...
The bottling could be avoided if you stick with the ales "British style", flat pumped or poured into glass (and there are some very decent ales suitable for this treatment) or by using CO2 carbonation units for the whole quantity.
It is doable but does it worth it?
I brew my beer at home because I like it and my calculations are it is not considerably cheaper than decent quality store beer. Maybe, if you control your costs and compare the final product to Bud, it makes sence $$wise, but when you add the boatlife realities...