I was talking to Bob Saunders of Superior Dive Works yesterday, and he was telling me that the hull bottom growth has been terrible this year, and there has been a brown carpet-like fungus that grows from the bottom up. So far, it has not been marina specific - just all over. They are having to scrape the fungus off and they wipe the bottom. Obviously, this requires more time and more frequent cleanings.
I mention this because if you are set up for quarterly cleanings, your bottom may be not as clean as you expect. You should always have your bottom cleaned before each race, but if you do not clean the bottom everytime, you are leaving a lot of boatspeed on the course.
Bob's diver who cleans Stinger's bottom told me the same thing some time ago. I have also seen a lot of the yellow algae in my pool. Never have had trouble with that before. Harvey? Warmer water?
I have Bob's crew clean Stinger's bottom as often as possible. Certainly before every race, including the Icicle and Rum races. If you are racing and not doing that, I can vouch for the fact that your boat gets slower as time progresses.