With the single V belt on a 110 amp alternator on my Yanmar, I had to cut the output to about 50 amps and still got a lot of black dust. I bought the flat belt kit from the company in upstate New York, expensive but their customer service is great, and now can get 100 amps out of the alternator with no dust, and haven't had to adjust the belt since installation.
That and swapping engines from a 2 gm yanmar that just couldn't push a 7 ton boat against 20 knots and some chop to a 3gm yanmar that can do all that and more. Headed down the ICW now, getting in an hour or hour and a half earlier every day. Just realized the other day that it does mean I burn more fuel, was close to running out pulling into the fuel dock and didn't even realize it.
Lots of wind in South Carolina for the next couple days.