Re: What's with the slime??
How long a bottom paint lasts will depend on how many layers you put on. One layer, 12-18mos round here. 2 layers, 36ish. Also, FB tells me that regular gentle scrubbing will tend to extend the life of the bottom paint, as opposed to infrequent hard scrubs.
I also tend to get barnacles (SF Bay), on the prop and the rudder. My theory on the rudder is that the propwash causes accelerates the "ablative wear" of the paint, as my rudder barnacles are almost exclusively directly behind the prop.
Some slime is inevitable - but generally bottom paints work really well. I accidentally let my power cord hang in the water while I was away for a month. I swear I got about 1 foot of weed hanging down from it; the hull was bit slimy, that is all. Well, very slimy. But no foot-long weed trailing...however, the prop was invisible behind a soccer-ball sized ball of weed!! In 4 weeks! Sheesh.