My answer to What are popular method to clean hull for big boat?
Answer by Desmond Last:
Hello Jimmy. I can only answer for Australia where I owned Sydney Boat Sales for 12 years until a Criminal Group undermined my business. I am returning to Sydney shortly to arrest those involved.
There are several methods.
The first and popular on larger boats is hull diving. This is where a diver will dive on teh hull from his work-boat and scrape and blast the marine growth off. Some authorities do not like it as the growth and any residue of anti-foul paint will then pollute the local water. Race-yachts do not have anti-foul they are scraped before every race.
You can also put the boat on the slip or travel-lift. You can water blast the hull for anti-fouling or for sandblasting.
When the anti-foul builds up after several years of anti-foul it is a good idea to tke it back to the bare hull – though you will need to primer the hull to prepare for the anti-foul.
Environmental considerations are important and the residue from cleaning should go thought a waste trap so the water can be cleaned. Non polluting anti-foul paint should be used.
Whenever the boat is slipped the skin fittings shoudl be checked and plastic which becomes brittle overtime replaced with brass. The hull should be moisture (fiber-glass) checked for osmosis, steel for rust, timber for re-caulking and rot. Rudder bearings checked and any anodes replaced. Rudders should also be checked for water ingress.
What are popular method to clean hull for big boat?
