tophatyachts.com

Hi All,

The antifoul on my MkII is getting too thick and is flaking in places. The local marina has suggested that I should think about stripping off the antifoul totally and repriming before recoating (they quoted about $3K to do this). To save money I am tempted to just give the hull a heavy sand to take off a few of the old layers and to ensure the new antifoul has a firm base, spot prime and put an another coat of Altec 5.

Is there and problem in putting a complete struip off for a year or two? I would be interested to hear what others have done.

Cheers,
Mark
Storm Petrel (MkII)


Strip the whole lot off you will probably save 60-70 kg's. We did it and won the next race by 2 minutes. Get rid of the old stuff. You won't know your self.
Cheers
Johnno
Sombrero R1421

Ouch, $3000! That's one of the jobs I have to do at some stage (after making sure the mast stays up and we don't sink at the mooring, etc).

How would the marina remove the antifouling? When I got my boat surveyed at purchase, the surveyor said to get it sandblasted below the waterline at some stage. But I was reading one of Don Casey's DIY boat repair books and he says never but never sandblast a fibreglass hull because it makes the gelcoat porous and sets you up for osmosis down the track, which is a nasty prospect.

Cheers

Peter
Dragonfly


I am faced with a similar job on Tales and are wary of sandblasting too.
Dry ice blasting is available and sounds much safer. I am planning on getting a quote soon so will post details then.
Cheers,
Tom

The $3000 included complete removal of the old antifoul (by a subcontractor), priming and new antifoul. I think they use a chemical stripper because he said it only takes a couple of hours (the marina swears by this method). I have been warned that sanding would take about two man-days and if you do not do it yourself would cost about $64 per hour for labour plus material costs.

I do not race my boat and I am tempted to just sand off enough of the old antifoul to form a base for the new antifoul. If I had the money I would go the whole hog as Johnno suggetsted, but there are probably more importntant things I could spend it on - like a new main. A picture of my boat showing the thick antifouling is attached.

I will be interested to hear what they quote you Tom and anyone elses opinion on this.

Cheers,
Mark
Storm Petrel Showing thick and peeling antifouling.doc


Mark,

If I had to do that I would be considering getting the bottom done with cop-r-bot which could last for 5-10 years. That means only going up to check seacocks etc. on the odd occasion.

Phillip
SEAKA


Hi Mark
The girls with the previous reply obviously dident need their bottoms sand blasted . My boat has a thick coat of old antifoul on it. I got quoted by soda blast $1800 to remove. I opted to use some antifoul stripper and got off about half. I then coated with a different colour and will go again next antifouling. I found when giving the bum a scrum on tuesday that some spots where the antifoul has flaked off. I have friends that have removed their antifoul with chisels. 3 guys overs 2 days, little by little. Horrible job but no easy way. Re Prime and start again.
Cheers
Phil


Hi Mark

Its best to totally prime rather than spot prime. Also, check for osmosis before you start work. Hempel system is better value for money. A quick sand after Peel-Away stripper ( No 6) will do.

Antifouling part of my trade - happy to give any further advice.

Brett


Some advice i got given last time I enquired about having antifoul removed professionally was to wait till winter when marinas are less busy and more negotiable on price.

I wonder if we could line up a group deal if 3 or 4 of us wanted to have antifoul strip and repaint doen at once??

Gavin
Wigwam


Gavin,

If you're based in Pittwater, happy to join in. I'm due for my annual recoat shortly - haven't been stripped back since 99.

Mark


Hi Brett

The antifouling stripper sheets you are recommending sound like a neat, painless and environmentally friendly solution. Looking on the web I found a brand called "Hull-Strip" and another called "Peel-Away". Have you any experience with those? I couldn't find a site for Hempel Paints.

How long does the stuff stay on for? (I'm thinking of the cost of sitting on the slipway for days)

Is there a risk of the stripper softening the gelcoat?

You also said check for osmosis before you start, but I don't quite understand that. Wouldn't you want to remove the antifouling first so you can more easily check for osmosis bubbles?

Lots of questions, but if you have answers to any of them, I'd be really grateful.

Thanks

Peter


Hi there Peter, I hope you dont mind me putting my nose into this thread.
I stripped my previous boat, a fibreglass bluebird, with Hull Strip a few years ago. In my opinion and I dont have experience with any other products, Hull Striip worked a treat. It is the consistency of porridge (almost) and I put it on thickly with a 3" brush. Grease proof paper is gently pressed onto the hull strip once it has been applied so as to prevent it drying out in the process.
I left the treatment on for about 8 hours and then came back with a wide stripping knife and set to it. The paper, hullstrip and antifoul came off in big sheets (all stuck together) like wet newspaper. There was no softening of the gelcoat in any way.
The thick sheets of waste were then easily collected off the ground ( a large tarp under the boat helps here) for disposal.
The clean hull can then be inspected for osmosis which may not be evident under thick antifoul.
A quick sanding with about 80-120grit paper on an orbital sander gave a key for the subsequent application of epoxy layers and "Interprotect".
The "Hull Strip process including the sanding only took 2 days on the bluebird.

Cheers for now
Austin

I recently went through this excercise. I scraped off the old stuff with a tungstan scraper. Took about 3 hrs a side. Filled the gouges that i caused when getting impatient with epoxy. Then gave 2 coats of interprotect prior to antifouling. Cheap, and effective.
Cheers
Phil

Ive got a big job ahead of me this year removing maybe 10 years (or more) of build up on the bottom of my mk 3.

Im not racing her, so speed is not the be all and end-all, though it would be nice to have a cleaner bottom and may save on the fuel consumption somewhat

Im going to have to hard stand her for about a week, to strip and grind out a bit of ozzy and do some general repair work. Has anyone else used this hull strip product? is it as straight forward as many suggest?

How easy is it to repair osmosis? Is there a general rule on proper curing/drying out time for such a procedure?

Also, whats the best bet for buffing above the water line, she's a little chalky/dull and would be nice to get a good shine back if possible


cheers
dan

I slipped my Mk3 after an extended period without antifouling. Needless to say, I had a fair bit of growth below. I originally planned to only have out of the water for the weekend, but when water blasting it sections came off right down to the gelcoat. I decided to take it all off and reapply the expoxy before antifouling again. It took me two days using the blaster to get the bulk of it off. My doctor thinks I may have torn a ligament from the repeated jerking of the blaster. The small amount that refused to come as sanded off by the marina staff who also did a few minor fiberglass repairs, reapplied the antifoul and polished the hull. I was on the slip for a total of 10 days, but was given the last 3 days free.

This was about 4 weeks ago. I finally got the invoice a few days ago. $3950!!!. Not happy at all, especially with the poor job they did. They failed get to all the stains off the white hull when acid washing it and then polished over the top of the stains and left mould at the stern. The polishing was very patchy with whole sections missed. I suppose there is not a lot I can do about it. I repeated asked how much I could expect to pay before and while the work was being done and was told that "We'll look after you" and that they'll try to keep costs down.

G'day Richardm you have my sympathy, seems like an excessive amount for a poor job i hope you have some success with the boatyard redoing your polishing at least. Regarding the subject of removing stubborn old anti foul,i,m working in a boat yard at the moment where they use a very high pressure spray to do this about 3000 psi and it does a remarkable job , i have not done this my self but i have seen the results,not much left to remove by hand ,it seems to me this is worth a try ,does any one know of a problem with this method......Cheers taunto

Bringing up an oldish subject here

My mark 3 is (over)due to come out of the water, have been somewhat pre-occupied with other matters..

My question to you all is, just how much of a performance increase could i expect from stripping back all the old antifoul? I need to weigh it up against the cost (aesthetics aside). Im not racing or cruising long-distance so performance is not really key to me, id rather spend the 000' on a spanking new headsail, furler and chartplotter

thoughts anyone?

Hi Dan,
Dont think you'll notice much, if any difference if you strip the old antifoul off, others may disagree, ive not had very much experience with antifouling to really comment.

In your earlier post about restoring the chalky hull, ive had a good result by loosely following some advice that was on cruisersforum (post by maine sail) here:
http://www.cruisersforum.com/forums/f55 ... 235-2.html

On the slip, before antifouling i gave the hull above the waterline an acid wash & a very fine sand with wet & dry sandpaper, then after antifouling i taped just on the new antifoul with that masking tape that has a little plastic skirt (so i would not smudge the new antifoul onto the white hull sides with the power buffer/polisher.
Then with the power buffer used a buffing/cutting compound (K&T brand), then used meguires #7 i think its called by hand, then finished with Nu-Finish polish (in the orange bottle, i found it at Auto-Pro) by hand.
Unfortunately i ran out of time on the slip to finish the job entirely, but was happy with the area i did finish.
Having to finish the work while back on the mooring.

Hi guys as for sand blasting a hull try to get the guy who is doing the job to guarantee in writing how far he is going to go.... he cant.... SO DONT DO IT.... you will end up losing some of your precious boat even if its only a small amount.... old fashion hard work with the electric sander will do the job and a lot less messy than those gells.... A case of the good old marinas making a killing.... if you still want to spend the three grand give me a call i really need the money

The other option is soda blasting. Apparently it works as well as sandblasting, but doesn't go as far as the sand....

http://www.sbasodablastaustralia.com/index.htm is the first link a Google search comes up with.

Our guys in the car club swear by it....

DISCLAIMER - I haven't tried it, and have no real idea how good it is from a personal level, just anecdotal evidence. Your results may vary....
Michael

Well Auriga is out of the water for the next 3 days on the hard stand,

I had intended to take to the old antifoul with some very course wet/dry paper however the shipwright just didnt think it'd be worth the effort (rightly so!)

Instead we're going to let the antifoul dry up a bit over the weekend then hit it with the high pressure hose on Monday which he thinks will remove a fair bit more than i would by hand. A little bit of rubbing back by hand before spot priming and repainting she'll be back in the water

Dan