BMS - if you think Savannah water is bad come on south to New Smyrna/Daytona area. Yes I use prop speed and its a great product. Barnacles will fling off when the props start turning. Make sure its applied correctly or it will not stick to props.
Not quite that bad here, a lot of hulls get cleaned every two weeks but others let them go a month. The growth slows considerably in the winter months.
Application is critical with prop speed and you still get growth on it, but it falls right off when the wheels turn. HOWEVER, electrolysis will peel it right off in a hurry. So if the boat eats zincs, the prop speed will be gone in a month for sure. It it's a boat where zincs last 6 months, then if applied properly, it will work very well and you'll usually gain 30-50 rpm's with it top end from what I've seen.......