How do you clean the bottom?
I already cleaned sometime the bottom of a boat and it is a hard work. If the length of your boat is bigger than ten meters I don''t recommend you unless you dive with an aqualung or you have a very big lungs.
To clean the bottom, the best is water at full pressure although if you have time you can also use a spatula taking care of the paint.
The best solution it''s to take off the boat from the water, to clean it on land and to paint the bottom with a special paint to avoid seaweed because if you don''t do that, you will have to dive for cleaning every months.
Another good solution: don''t clean it and wait until mussels have a good size to eat them.