Why once a month in South Florida
Growth on a hull comes in stages. In the first weeks a soft film of slime forms. Within a month or two, algae follow — the green or brown beard you see at the waterline. After that, barnacles and oysters start to settle, and they hold on hard.
In colder places growth slows down for the winter. In Miami the water stays warm all year, so it doesn’t. A monthly cleaning takes the hull back to clean paint while the growth is still soft — before anything hard can attach.
When to clean more often
Every two weeks makes sense for yachts that are kept show-ready, and for boats that sit at the dock for weeks without running. A boat that moves sheds some growth; a boat that sits in warm, still water — a canal or a quiet marina — collects it faster.
It also pays to clean right before a long trip, a race or a sale, when speed, fuel and the look of the hull matter most.
After a new paint job
With fresh antifouling, the first cleaning is usually about 3–4 weeks after launch. New paint is at its strongest, so the first months need only a light cleaning — the point is to keep slime from building up, not to work the paint hard.
What waiting costs
The longer the gap, the longer the job. A 45 ft boat cleaned monthly is $303.75. At about two months since the last cleaning the price is × 1.5 — $455.63 for the same boat. After three months or more, barnacles and oysters have taken hold and the work is charged by the hour, $150 per hour, with an estimate first.
Waiting costs the boat, too. A fouled bottom is slower and burns more fuel, and scraping off heavy growth wears down the bottom paint that protects the hull.
Signs your hull is due
A green or brown beard at the waterline. Lower top speed or more fuel at the same RPM. A hull that feels rough to the touch. Or simply more than a month since the last cleaning — in Miami, that is reason enough.