Hi All,
Boat bags were all the rage 10 to 15 years ago. They did work.
They were easy to get in and out of. There was a rope on either side at the back that you used to pull the boat into the bag with and then just pulled up to the quarters. They usually had a floating chlorine dispenser that had a pool tablet in it. The chlorine killed everything. They took up no more space than the boat they were intended for.
At one stage Maritime were going around sampling the water and fining boat owners if they had anything different to seawater in the bag, even fresh water. Yes fresh water is a pollutant.
I'd check with maritime to see if they are legal and how to use them if you're thing of getting one.
Cleaning off your boat in the water is also a no no.
I was thinking how practical those small floating docks are. Why not just raise the boat out of the water on the mooring. You don't need antifouling at all, you can have a perfectly smooth bare fibreglass hull, the boat can't sink.
Greg