"How often should my boat's hull be cleaned?"
This is a question hull divers are often asked. It is a common misconception that frequent hull cleaning reduces the length of time your anti fouling paint remains viable. But by employing an experienced, knowledgeable hull cleaner using Best Management Practices, quite the opposite is true.
The key to making your anti fouling paint last a long time is to never let it get so dirty that it cannot be cleaned with the softest cleaning media (and by that we mean carpet or a white pad.) A typical hull cleaning frequency here in the San Francisco Bay Area is every three months. This schedule virtually ensures that within the first year, your diver will have to clean the boat with something more abrasive. And that means scrubbing paint off unnecessarily which, of course, shortens your paint's lifespan. A typical bottom job cleaned on a quarterly schedule will last about two years.
You paid a lot of money for your bottom job and you want it last as long as possible. Here in the San Francisco Bay Area, a 2-month cleaning frequency is recommended.
This ensures that your diver can use the softest pad when cleaning your hull, often for the entire life of the paint. A less frequent regimen means a more abrasive pad will have to be used, which not only shortens the lifespan of your anti fouling paint but releases more copper into the water than otherwise would be. Further, with the 2-month cleaning cycle, your hull is clean more of the time, thereby improving performance both under power and sail and reducing your fuel consumption and carbon emissions. By gently cleaning your hull just 6 times per year (as opposed to 4 times) your bottom paint can last three years or more, potentially saving you thousands of dollars in haulout/bottom painting costs.
Here's the math for 10 years of ownership of a 40' sailboat:
3-month hull cleaning schedule (painted every 2 years)
$2700 bottom job X 5 = $13,500
$90.00 hull cleaning (4 times/year X 10) = $3600
Total expenditure (10 years) = $17,100
2-month hull cleaning schedule (painted every 3 years)
$2700 bottom job X 3 = $8100
$90.00 hull cleaning (6 times/year X 10) = $5400
Total expenditure (10 years) = $13,500
Total savings = $3600
That's quite a savings. Not to mention your fuel cost savings from operating the boat with a clean bottom more of the time. And consider also that the cost of the bottom job is only going to increase in the future.
The fact is that relatively frequent, gentle cleanings are better for the boat, better for the environment and better for your wallet than less frequent, more abrasive cleanings. Ask your hull cleaner if he is a member of the California Professional Divers Association
. CPDA divers are trained and certified in the use of industry standard In-water Hull Cleaning Best Management Practices, making them the best trained, best educated hull cleaners in California.