Returning antifouled hull to shiny gelcoat?

SnaxMuppet

SnaxMuppet

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I am not thinking of doing this... i need my antifoul!

But I am about to start dry berthing at Yacht Haven Quay, Plymouth and they are doing a special offer to blast off the antifoul from the hull and return it to a shiny gelcoat.

Can this be done without risk of damage to the hull? My hull was etched with a hand-sander prior to priming, as many properly prepared hulls have been, so if the antifoul was blasted off I imagine it would take a fair bit of work to return it to shiny, undamaged, gel?

I am curious... has anyone had this done and how successful was it?
 
Long John has. Did it just up the Cattewater. Slurry I think. Anyway, ask him.

Mind you, I would not think yours needs doing for another ten years. Whilst, I think I've got about 20 coats on mine.
 
I wouldn't do it to mine because of the Round Britain but they are putting it forward as an option of boats that are starting to dry berth because they are then out of the water most of the time and they say why carry the extra weight?

Personally, I am pretty sure that the extra weight won't make that much difference to the fuel consumption and so IMO it isn't financially worth it... but I could be wrong!
 
Gel coat is normally pretty thin. So if you take off all the antifoul, and then try to get the gel coat back to shiny condition, you may have to take off a fair bit of gel coat once you rubbed down and polished past the initial preparation. It all depends what was done to it initially, and how thick the gel coat is. Did you do the sanding yourself, and if so, how much did you take off the surface of the gel coat, and how deep did you sand in the deepest 'scratches?
 
That is pretty much I though BrendanS... I am not actually thinking of doing this myself so your I can't really answer your questions. I was more interested in the idea of whether it could be done safely mainly because the marina advertised it as a service that was available. I was surprised that was all.

More of a general interest thing rather than a "I want to do this" thing.
 
It's not going to actually harm the hull as such. If you really want to have the antifoul removed, and restored to a shiny surface, you might want to talk to a specialist about a two pack paint job. Have a look at some of the pics Lakesailor has posted about some paint jobs he's done on hulls when restoring. Probably better than trying to polish up gelcoat that's been primed and antifouled, though others will have much more idea about this than me.

I guess the other question would be if the antifoul you have now is hard or soft?

Not really a lot of point in having antifoul on a boat that's drystored, so the other option is just to remove it, and live with slightly scuffed up gel coat?
 
Hi Paul, Ive done exactly what your mentioning and I will say, although it was a pig of a job it did make a big difference getting those extra knots. It also showed up a few defects in the gel coat which I got repaired but also showed what a terrible job a local company made of fitting the bow thruster (another long story!) which I was quoted £600 to get looking right as it looks like a carbunkle (Spelling?) at the moment.

Anyway, Im at YHQ so if you want to come over anytime to have a look just let me know.
 
Hi,

Just to clarify any confusion, or a misapprehension that it's "sell job" by Yacht Haven Quay; we don't offer this service, and never have done. We do advocate it as being sensible, as over the course of a season or two, the smoothness of a polished, unantifouled hull below the waterline will have a small bearing on speed and economy of your boat. One of our tenants, Biojet, specialises in this work and offers a discount to YHQ customers. I'm even going to have my own RIB done (when I can afford it!!)

Regards,
Will
 
A few years ago at lift out a friend had his 1987 Fairline corniche at the side of my 1988 corniche.
He wanted me to join him for a slurry blast of 'gentle soda'.
I wasn't keen even when offered a two for one deal and declined.
My mate went ahead and I saw the damage the following weekend

Whole hull was riddled with small holes in the gel coat.
The whole boat had to be filled and epoxy coated.
At some stage a section of 1 ft by 2 ft on my bow had also been blasted.
It is unclear if
they started on the wrong boat.
they hit it by accident
they wanted to see if my hull would also be wrecked
they thought it was such a good job I would want mine done


My 'test' section was also covered with pin prick holes that I needed to fill.
I was pleased a small section had been tested as it confirmed to me that GRP shouldn't be grit blasted unless it needs an osmosis treatment.
A friend was then kind enough to clean my hull with an electric chisel, the old antifoul came off and left beautiful white shinny gelcoat with no visible signs of weakness.
It is clear that older boats have naturally occurring bubble holes deep within the gel coat that are created during the mixing. These bubbles are fine and will not cause a problem unless the Gel coat is overpolished with compound, over sanded or slurry/grit blasted.

The slurry blast had not made the holes but it had exposed voids that had been water tight for 15 years (moisture reading were very good).

The grass under the treated boat has still not grown back and turned into a bog for a while.

From my experience I would only have a slurry blast on a modern boat that had used a vacuum technique to mix the gel coat and so reduce the amount of bubbles.

If you read the professional sites they warn about this in a round about way " leaves a nice key finish ready for filling and epoxy coating " shouldnt the surface be ready for AF Primer ?


Check out Lidls, they have a scapper on offer this week /forums/images/graemlins/smile.gif
 
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