Antifouling - Splash'n'dash or back to Gellcoat ?

[affinite]

My (GRP) boat is currently ashore for the winter in Greece .
The surface of the hull s rather pitted and rough with old AF paint and I'm thinking about antifouling options for next year.
In the past Ive just had the yard do a light sand-down and apply a couple of coats of AF every season (or two).
The result looks OK (from a distance) and seems to do the job of preventing growth pretty well
This year the yard have suggested that its time to strip off (soda blasting) all the old paint, back to gel-coat and then repaint "properly" with multiple coats of primer and top coat,

Obviously splash'n'dash is a much cheaper option but Im wondering if there are any real benefits in stripping back to gel coat option ?
BTW - I'm a cruiser, not a racer

Interested to hear opinions

 

[Caer Urfa]

Repainting over old pitted antifoul is ok to a point but then you will find it flakes off over the season so parts of the hull do not get as protected as you may think and will get worse

Sand or soda blasting back to gel coat is a good idea if its getting bad BUT I would recommend you coat the hull after first with say 5 x coats of International Gelshield 200 then a primer then two coats of antifoul, not cheap and a fair bit of work but worthwhile in the end

 

[neil_s]

For myself, I'm not a believer in stripping the bottom for ultra smooth racing performance. I prefer to go over it with a pallet knife and shift the loose bits before slapping on a new coat. I'm not sure you can expect a boatyard to do this, though.

 

[johnalison]

Most boats will eventually get to the stage when stripping is worth doing. It happened to mine after about 14 years. I was not concerned about the performance, but there were patches of poor adhesion to the original layer and I got fed up with rubbing them down and re-priming them. In the case of the OP, it is hard to tell without seeing it, but it will do no harm if he puts it off for another year or two, but if the yard know their job, and the boat will be re-epoxied, it could be worthwhile. My boat went faster after being stripped, just as my car does after it has been washed.

 

[Bav32]

Wou

Most boats will eventually get to the stage when stripping is worth doing. It happened to mine after about 14 years. I was not concerned about the performance, but there were patches of poor adhesion to the original layer and I got fed up with rubbing them down and re-priming them. In the case of the OP, it is hard to tell without seeing it, but it will do no harm if he puts it off for another year or two, but if the yard know their job, and the boat will be re-epoxied, it could be worthwhile. My boat went faster after being stripped, just as my car does after it has been washed.

Would you not like to cruise 1/2 knot faster and point a few degrees high every day you are out "cruising"?
If so you know the answer.

 

[johnalison]

Wou

Would you not like to cruise 1/2 knot faster and point a few degrees high every day you are out "cruising"?
If so you know the answer.

I would, but how much money is a tenth of a knot worth? I ‘think’ my boat went a little faster after treatment, but I don’t think it was as much as half a knot.

 

[Biggles Wader]

My (GRP) boat is currently ashore for the winter in Greece .
The surface of the hull s rather pitted and rough with old AF paint and I'm thinking about antifouling options for next year.
In the past Ive just had the yard do a light sand-down and apply a couple of coats of AF every season (or two).
The result looks OK (from a distance) and seems to do the job of preventing growth pretty well
This year the yard have suggested that its time to strip off (soda blasting) all the old paint, back to gel-coat and then repaint "properly" with multiple coats of primer and top coat,

Obviously splash'n'dash is a much cheaper option but Im wondering if there are any real benefits in stripping back to gel coat option ?
BTW - I'm a cruiser, not a racer

Interested to hear opinions

As long as this remains true why change the regime?

 

[jwfrary]

Repainting over old pitted antifoul is ok to a point but then you will find it flakes off over the season so parts of the hull do not get as protected as you may think and will get worse

Sand or soda blasting back to gel coat is a good idea if its getting bad BUT I would recommend you coat the hull after first with say 5 x coats of International Gelshield 200 then a primer then two coats of antifoul, not cheap and a fair bit of work but worthwhile in the end

Use hempel light primer about half the price, does the same thing

 

[CAPTAIN FANTASTIC]

If you dont race there is no need for a "smooth" hull; give it a good sanding and then antifoul.

 

[Elessar]

Repainting over old pitted antifoul is ok to a point but then you will find it flakes off over the season so parts of the hull do not get as protected as you may think and will get worse

Sand or soda blasting back to gel coat is a good idea if its getting bad BUT I would recommend you coat the hull after first with say 5 x coats of International Gelshield 200 then a primer then two coats of antifoul, not cheap and a fair bit of work but worthwhile in the end

good advice.

however it is gone to the trouble of going back to the gelcoat I’d Coppercoat it. And No more painting for 15 years.

if he wants ordinary antifoul I’d do as you suggest.