Antifouling Bare hull ?

[Brookey]

Well I've decided after reading many of threads already on here to get my new to me prout 33 (first proper yacht) wet blasted, as it seems to have as many layers of old antifouls as years its been in the water, and I don't have the time or will power to spend scraping away underneath.

My question is though assuming all goes to plan and no major osmosis found and left with an intact gel coat what would you recommend for then re antifouling, and what base coat primer etc would I require. Don't think I want to go down the copper coat or similiar route as quite happy to reapply antifoul each season or two as required once I know what I'm going on top of.

And if osmosis is found (probably likely) what action can I take.

Anyone fancy giving a newbie some advice, anything appreciated.

 

[Pasarell]

Welcome to the forum. Surprised nobody has answered yet but this will get you back to the top where it will be noticed.
If the boat is blasted there will be at least a small amount of erosion of the gel coat, possibly quite a lot, so worth replacing that barrier coat. Epoxy is the most common to use. Lots of them available but look carefully at the instructions as temperature during application, and temperature variations between coats will be important to a successful job. If you are outside it is unlikely the weather will be suitable before late March in the UK.
You could also use a conventional primer like Primocon but since you have all the preparation done for an epoxy it seems to make sense to go that route. Make sure you put enough coats on to be worthwhile. Depending on the product you use 4 will be a minimum and probably more. Same applies to both epoxy or conventional products.
If there are any damaged areas in the gelcoat fill them with a solvent free epoxy filler before priming.
If you find osmosis you have to choose what route to take, ranging from ignore through to expensive full treatment. You will get plenty of advice, not all informed, from "no boat has ever sunk" up to "essential to pay £'000s without delay. First thing, in my opinion, is to understand the scale of the problem and make your own mind up about cost of repair v value of boat. If the problem is minor you can grind out the blisters, wash thoroughly, lea ve to dry as long as possible then fill and coat over. If the problem is big you may be advised to get a surveyor involved, but find one with a good reputation and explain exactly what you want his opinion on. If you have a good local yard their advice might be the best to take even though they will be trying to sell you something.
Get the blasting done as soon as possible. That way you have some time before you can prime the hull to evaluate any problem and deal with it. Also some time to dry out will not be a bad thing even though it is too short for any great effect.
No doubt there will be plenty of other advice along shortly now you're back at the top

 

[pcatterall]

If there are no obvious signs of blistering then you could justwash the hull scrape off any loose bits of antifoul and bung on another coat and focus your attention elsewhere.
If you are determined to have it blasted then it will be well worth considering doing a proper job, moisture readings and if all ok then full epoxy or top up epoxy if there are some coats on already. Have you the boats history or old surveys.
I did the full treatment last year and will send you the info if you wish.

 

[oldsaltoz]

Well I've decided after reading many of threads already on here to get my new to me prout 33 (first proper yacht) wet blasted, as it seems to have as many layers of old antifouls as years its been in the water, and I don't have the time or will power to spend scraping away underneath.

My question is though assuming all goes to plan and no major osmosis found and left with an intact gel coat what would you recommend for then re antifouling, and what base coat primer etc would I require. Don't think I want to go down the copper coat or similiar route as quite happy to reapply antifoul each season or two as required once I know what I'm going on top of.

And if osmosis is found (probably likely) what action can I take.

Anyone fancy giving a newbie some advice, anything appreciated.

The chances of having an intact gelcoat and no sign of the big O are remote, wet blasting will find all sorts of minor pin holes and perhaps some old repairs.

If you plan to keep for some time you should consider using one of the many shield coats or an epoxy, then think about antifoul and the right primer/s.

But even before all this, have the hull checked for moisture content as sealing the moisture in will be another problem down the track.

Good luck and fair winds.

 

[nigelmercier]

I've decided .. to get my new to me prout 33 (first proper yacht) wet blasted ...

If I were in your situation, I wouldn't consider anything other than CopperCoat.

 

[Twister_Ken]

If I were in your situation, I wouldn't consider anything other than CopperCoat.

Ditto that. You loose the chore of redoing a/f every year which is bad enough on a mono. On a cat you've got getting on for twice the surface area to do, and working low-down between the hulls must be a real PITA.

 

[Caer Urfa]

Anyone fancy giving a newbie some advice, anything appreciated.

If your going to the expense of having all the old antifoul blasted off you would be mad to just consider directly anitfouling just the bare Gelcoat.

Primocon is a primer and is not suitable to apply over the bare hull, once the hull has dried you need to clean it with something like International thinners No7 (wear protective clothing and glasses) then jet wash again and allow to dry.

Then probably 5 coats of a protective coating like Gelshied 200, THEN a coat of Primocon then 2 coats of whatever antifoul you like best.

The results will last you for many years and you will just need antifouling when required, BUT, make sure you have at least 5 degrees IN THE NIGHT for good curing process when you apply any two pack epoxy, not just in the day, 8-10 degrees in the day will be also be better for the applications.

All the above can be applied with a roller.

Mike

 

[A1Sailor]

I blasted then epoxied my Sadler25 years ago - in the month of May. February just doesn't seem the right time of year to do anything other than re-antifoul imho.

 

[Brookey]

Thanks everyone for all the replies and thanks Pasarell for getting me back to the top.

Looks like I might have to have another look at the copper coating again only really rulled it out due to the quite timing/temperature critical nature of applying the coats.

If I go down the epoxy or copper coat route from what I understand making sure the hull is dry seems to be one of the main concerns. The boat should be blasted in the next week or so hopefully if it warms up a bit, but the crane for re splashing is booked for end of March. If i wait till the weekend befor to do the bottom would this be long enough to dry the hull out, (should I try to tent the boat or is it better to let the wind get to it?)

And as the water tanks are moulded in the hull keels is this a problem.

Thanks in advance

 

[Monique]

If I were in your situation, I wouldn't consider anything other than CopperCoat.

Me too. The big O repairs, epoxy application, epoxy primer... Why just stop short?

 

[Marine Reflections]

If I were in your situation, I wouldn't consider anything other than CopperCoat.

+1