What if I don't clean the hull?

The RIB stands in my yard on its trailer. It has been in the water for 7 months and despite the expensive white anti fouling came out with a lot of marine growth.

Everything substantial now has been removed with the pressure washer but still it looks far from clean. I would normally crawl under it armed with sanding paper or steel wool and stay there until the gel coat is white again, but at my age that's real agony.

What if I don't clean it? The waterline in bow area I can reach without too much effort, but everything else I can see only when the boat is on the trailer. Will an occasional full throttle run at 35 kn not be enough to keep the growth under control?

 

Did anyone ever hear about results from the forumite who rubbed his hull with, IIRC, coconut oil because some old timer once told him he'd never seen barnacles on a coconut?

 

Spray it with some bleach before pressure cleaning it again, imo. I doubt the coconut oil will repel much, but might leave a nice fragrance and a small slick !

 

I'd do nothing until you are ready to splash it again (springtime?). Benign neglect has its virtues.

 

I've seen plenty of coconuts washed up that had obviously been at sea a good while ( the contents is almost always inedible), but can't recall seeing any barnacles attached. Maybe I'm not a good observer of such things. If they come ashore clean, it would be interesting to know why.

 

Someone gave me a spray can labeled "scale & rust remover" that helped removing the brown belt around the waterline. I didn't dare using on the tube because it contains 30% hydrochloric acid, that may harm PVC and the glue.
Bleach seems less aggressive, it is worth a try.

 

White paint is always going to show stains, maybe you could rub it in the affected areas with a household cleaner like "Jif".

 

Get a piece of PVC and douse it with HCl also known as muriatic or hydrochloric acid as a test. I doubt it will be harmed because the Chlorine is already in the plastic. The CaCO3(or unprotected skin) will definitely be dissolved by HCl.

 

PVC itself is quite inert for both caustics and acids, but I am not so sure about the plasticizers in it. They are much less stable and are affected by exposure to UV, solvents and to a certain extent even seawater.

There is also the problem of finding the right equipment for spraying HCl because it rapidly attacks anything containing copper. When I used it to clean the Mercruiser legs on my previous boat I sacrificed a household spray can that survived less than 3 minutes until the acid had dissolved the mechanism.

To apply acid on a 6m RIB I need something more durable wit a long spout so I don't have to crawl under it.

 

Have you tried an all plastic garden sprayer?

http://acehardwaremaldives.com/product/lawn-garden/7215031/#.VlRiVDZdFlY

 

Frankly, I don't know if "all plastic" exists.
The sprayer I use for pesticides looks a lot like the one from Ace Hardware, but both the pump and the valve in the pistol grip contain metal parts like valves, valve seats and springs.

 

Brick and Mortar cleaning fluid is a more dilute version of Hydrochloric acid, maybe a bit kinder to an applicator? Might be worth giving oxalic acid a try, even a wipe with rhubarb leaves....

 

What happens if you don't wipe your butt, just knocking off the hunks?

 

If you can hire a kid up the block to lightly sand the remains scum of the boat without scratching the gel coat, I would switch the anti fouling paint to an ablative paint.
The ablative paint sluffs (sloughs?) off when running and leaves the hull looking clean when the boat is pulled.
You cannot pressure wash this though as the paint will come off with pressure

We switched to an ablative paint and applied three coats on our 40. It lasted 4 years ( 7 months in salt water, 5 months blocked) then a light scuff with 120 grit sandpaper and a quick wipe with the manufacturers solvent and then applied a couple of coats and are back in business.
Any growth that accumulates between trips disappears quickly at 20 knots.

 

I'm sitting here watching my sister with cerebral palsy, who won't even knock off the hunks herself at such times ... so I know all too well one possible answer to that question.