New fouling above the antifouling line

MM5AHO

MM5AHO

Well-Known Member
Joined
1 Oct 2007
Messages
2,553
Location
Central Scotland
Visit site
This summer is my first on a mooring after years in a marina.
I have now encountered fouling above the line of the anti-fouling where ferry wash and other wave action frequently wets the area.
Below the line, the antifouling is working OK - as well as before, and being soft antifouling, a vigorous sailing session seems to clean it up nicely. (self eroding doesn't erode with just the tide, needs a bit more speed)

My options to cure this seem to include:
* raise the top of the antifouling by about 100mm (might make it look like the boat is lightly loaded and floating too high?)
* add some different colour or antifouling (currently no different coloured "boot strap" or similar.
* vinyl wrap at that point (doubt this would stop growth)

Any other ideas?
Which cure might be best?
 
+1 for raising the WL, but beware that eroding AF will go hard when not immersed and is always the hardest bit to scrape off when you want to take it back at any point...
 
It is some years since I was on a swinging mooring, but in those days I used "boot-top" antifouling, but I imagine that hard scrubbable would do as well. Ultimately, there is no substitute for going round the waterline with a sponge or brush regularly, which is not hard when one has arrived in a dinghy anyway (unless you are posh and use a club launch).
 
I spent two hours scrubbing the waterline last week from lying in the dinghy. In retrospect, if I'd done its a few times it would have been easier, 4 months of growth. The difference between above the antifoul and below that line is astounding, and helps realisation of what a job that paint does.
Also surprising how tenacious that growth is, and how hard it is to remove. Stiff crush and a scouring pad to get it clean!
 
Not only is it hard to remove, but you can get pitting of the surface as well. I had a boot top on both my boats, a bit of a pain at fitting out time, but can look good with the right colour scheme and saves a lot of work during the season. Raising the waterline by a couple of inches does not look right, it is worth angling the boot top up a bit towards the bow as the wetted zone is a bit higher there I found.

I used to use Seajet for the main a/f and Trilux for the boot top.
 
I think that whether having the waterline a few inches above the, er, waterline looks right depends on the type of boat. On a high-sided AWB it helps to reduce the visual impact of the freeboard. On a low-freeboard traditional boat it doesn't look right. A different colour boot-top can look great, or can look too fussy again depending on the boat (and the colours) - it's also far too much faff for me, but then I'm lazy and prefer the simple look.
 
i have raised the water line on all 3 of my last boats precisely because og that same reason, 5 cm allround was enough and barely noticeable. besides , i think you will agree that looking at waterline paint is better than seeing the Green/brown streaks above a low waterline which looks nasty and makes the boat look uncared for.
 
Choose a calm day, wait until there's a gap between ferries, into the dinghy and spray the waterline with Sodium Hypochlorite solution (I had Dettol Anti-mould handy), leave it till the next ferry then wipe off anything left with a sponge. Repeat for the really stubborn bits. You could spray some oxalic acid on the yellow bits while passing!
 
Wait for a calm day and go round spraying the waterline with your favourite concentrate of Oxalic Acid. Green weed and brown stains will have disappeared by the time you have put the kettle on and had a cup of tea. Best to wait for a warm day (I know, I know) and do it a few times a season. Works for me at Kames where it can be a tad rough and the bow dipping in the sea is the worst part.
Donald
 
Our boot top is painted with Trilux.

This might appear a very odd choice but

Here in Oz our AF is sold in 4l or its nearest imperial equivalent. We use red for the hull(s) and the boot top needs to be a different colour. Trilux is sold for props, as well as hulls, and thus comes in 1l tins. If I bought 4l of black AF it would last for decades, so had to go for Trilux. Having 2 hulls its a bit too much to borrow. The boot top is just a bit wider than those little, cheap, paint rollers.

When we are in full cruising mode with all the water, fuel, extra fuel, life raft (this lot alone is 700kg) then + sails, food, drink the boot top becomes fouled, normally it would be just clear of splashing.
 
You must log in or register to reply here.

Share this page

Top