Eroding antifouling

NDG

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Is this stuff any good? My boat has been in the water for about 4 - 5 months and has got a nice coating of slime on it already (has been used a few times over the winter, but not much). If I dry it out against the quay and hose all the crap off, is is good enough to apply another coat with a roller straight over the old coat, or should I take all the old anti foul off with wet & dry or pressure hose and reapply from scratch? Presumably quite a lot will come off with a pressure hose when I hose the slime off anyway.

The stuff was applied by the last owner when I bought the boat, and I have no idea if it is any good or not. Does the boat need to be moving through the water a lot for it to be effective in keeping nature's finest off the hull?

Any views/experience gratefully received.
 

DoctorD

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Should be good. You can keep painting over antifouling (long as its clean - i.e. slime sprayed off) until the paint sticks no more (usually 3 or four seasons). Then you have to get all the old stuff off (usuallly with slurry) before starting again.

Be careful with high pressure hose - can damage gelcoat, but excellent for getting slime off.

What most people do (i.e. me) is wash down when boat comes out at end of season and then paint with anti-fouling before putting back in water. So long as paint goes on ok everything is fine.

In mid season I may take the boat out for a quick spray to get rid of slime/weed (e.g. before a long cruise or race).

You can also use some boat scrubber do-hicky as you are sailing along (forget the name).

Hope this helps - more knowledgeable people will surely improve on my response.

Graham
 

tonyleigh

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If you find an antifoul that combats slime tell us all!!! Provided you have neither weed nor barnacles it is probably doing its job though warming weather will accelerate growth. Most eroding antifoulings can be applied layer on layer but in time you will get cracking and flaking especially with the cheaper ones. Depending on your sailing water and the time you are stationary you can expect a coating of slime to build up (quite quickly in many areas) but a hose down or light wipe with a brush clears it.
 

Boathook

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Have only used eroding paint for the last 14 years. As the boat only comes out every other year 2 coats last for 2 years. For the first time had to 'sand' the bottom this winter to remove lose and flaking paint otherwise I just paint over the finish left by the yards jet washer. In the second season I will anchor in shallow water and sponge of the excess slime. The boat is moored in brakish water most of the time.
 

PeterGibbs

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Slime you have to live with - the only 100% solution is to lift the boat after every sail.

Anti fouling paint will adhere to any sound substrate. This is not really what the manufacturers' booklets say, but they are not inclined to inhibit us sploshing the stuff on, as you've noticed! Rubbing down with a damp piece of "green toast" will remove all loose material; I never work on dry anti-foul, it gets into your eyes and hair etc and is NO GOOD!

Anti fouling primer will strengthen adhesion if used where old paint has flaked off; just run it over the adjoining AF paint to give a serviceable substrate.

Removing all old paint is only necessary for racers who fuss over every micro crenulation that could inhibit glorious success round the cans. If they saved their money and put it into renewing their shot sails, they would be amazed at their turn of fortune!

For regular cruisers who've been at it some time, removing all the old AF is rare - usually to epoxy the hull for protective purposes. Giving the areas that are closer to sunshine (the first foot or so under the waterline) and best weed growth conditions a heavy blast of AF paint each year is good practice I think. Just one coat for the rest of the underwater area is probabaly effective for most conditions. If your conditions are such that you get heavy weed all over the underside by late June you will need to dry and scrape then whatever the paint you apply!

But getting rid of all loose paint is a basic - even I would ensure this!

PWG
 
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