If you can get Safe Boat Skin to work in the Solent, I will eat Des's hat
Stu and I have both had mixed results from antifouling but smooth gel coat will simply mean the antifouling just falls off, you really have to abraid it. Normally use the strongest stuff I can find from International with extra copper (tin has a red plastic top to it) but this year tried the cheaper XM antifouling. Lets just say I will be back to International in the Spring as the XM didn't stick very well and triffids grew all over it
The Solent has warm water, lots of nutrients and good tidal flow, all encourage things to grow on your hull. If thats not bad enough the mud will block the antifouling so she will need a good scrub during the season.