Hull has been soda blasted, to barrier or not?

[GrFa]

I read through the past threads on barrier and bottom prep and it seems the consensus is that barrier coats do more harm than good unless the hull is perfect (brand new) when you start. Our CD28 had the bottom soda blasted down to the gel coat in October, removing some 10-15 odd layers of bottom paint. She has been sitting shrink wrapped since with the hull below the waterline uncovered to dry. Now we are looking at what to do with the bottom before launch.

It appears there were a few fiberglass repairs in the past but for the most part the bottom is slightly roughed up gel coat. The rudder however appears to have been poorly glassed over at one point with glass mat exposed in areas. I assume the best remedy here would be a coat of epoxy, sand, then primer?

As for the rest of the bottom, which is just rough (blasted) gel coat. Would it be best to barrier coat it and then bottom paint? Or just a few coats of decent bottom paint? I was thinking a few coats of a decent ablative. The boat stays in the water from May-Oct in the Hudson. Thanks!

Greg

[Ray Garcia]

I would say now is probably the best time to apply a barrier coat. Fortunately our CD27 was coated by a previous owner and I do believe that it does help. The only hurdle in your situation would be to make sure the hull is thoroughly dry. No sense locking in the moisture. How long is long enough to dry? The longer the better. Since the hull was stripped back in October you should be good to go. I would prep everything else that needs to be done and save the hull work for last prior to launch. From my understanding applying the barrier coats is no harder than applying bottom paint. The albative is the way to go. I am sure I am going to get some dissension.

The rudder work should be done carefully. If you are dealing with dry lifting glass matt you may need to sand it back and apply new matting. A few coats of thickened epoxy to fair everything out, followed by a final coat of epoxy as a sealer should finish the job. This is not a very hard task to complete. Investing in a good sander and paper will help the process along.

It may cost you a little for the time and money. But with the barrier coat applied you will extend the hulls life sans the "pox". If you ever seen a badly blistered hull you know it is not a pretty sight. The whole hull blister topic is a Pandora's Box of remedies, causes, and examination.

Good luck.

[Cathy Monaghan]

Since your boat's bottom is down to the bare gelcoat and she's had time to dry out, my recommendation would be to go ahead and apply a barrier coat. I don't know where you keep your boat, but wait until the weather is warm.


Cathy
CD32 Realization, #3
Rahway, NJ
Raritan Bay

[Bob Ohler]

A surveyor who knows Cape Dories once advised me against the practice. As old as your boat must be, eventhough it has been out of the water since October, I would suspect that there is still some moisture present in the hull. Barrier coating would only seal in whatever moisture you still have. Just my 2 cents worth.

[Dean Abramson]

I have never really understood the "don't seal in the moisture" argument.

If there is some moisture in the hull, it seems to me that that is because there was some porosity to the gelcoat. If you do not replace the gelcoat with something (and I do NOT recommend more gelcoat), then it seems that the hull is even more exposed. So once it is in the water, it will start to take on even more moisture. I think I would rather take the chance on retaining whatever moisture is still there after an extended drying period, than to leave the hull unprotected.

Our bottom had to be sandblasted, then it was faired with epoxy fairing compound, then it got a barrier coat, then the bottom paint.

These are old boats and I'm sure they all have some amount of moisture in the hull. I don't mean to be argumentative with Bob (and I have heard this case made before), but I personally would want to protect the bottom.

(But then I do have a bit invested in my way of looking at this!)

My boatyard (and they knew they would not be doing the job) recommended epoxy. As the yard manager there put it, gelcoat is not a barrier, it is "a finish." I know you did not suggest re-doing with gelcoat; I just wanted to clarify that.

Good luck with it.

Dean

[Evergreen]

Soda blasting and barrier coating is the next best thing to peeling the whole hull and reglassing.

If you want a detailed explanation of both processes then check out the link on the Zahniser's Yachting Center Web Site. It is a well written article. It is biased towards peeling and reglassing but since then I have spoken to them and they are placing increased value on barrier coats due to their extensive experiences.

We had our CD36 soda blasted and barrier coated there last winter. So far the results are good.

[aja]

I agree with Bob and would not epoxy barrier coat. Don't waste your money and time.

Your Gelcoat on your Cape Dory is over 20 mils thick and a properly done soda blast job should have only removed 1/2 a mil. We had our 30 soda blasted and are just using bottom paint. Only had less than a dozen little blisters on the entire hull.

[Sea Hunt]

I just received my April 2008 issue of Cruising World, They have a timely article beginning at page 74 concerning repairing blisters, soda blasting, sanding & fairing, solvent washing the hull, applying a barrier coat (a two part epoxy ) (several layers) and finally painting the hull.

In addition, this article features several pictures of Robinhood Marine Center and Tom Fake, the service manager. I do not know Mr. Fake but I was at RMC last year for the CDSOA Maine cruise.

From everything I have read RMC knows their stuff. They seem to recommend barrier coating the sailboats they work on.

I should also mention that there is an article in the April 2008 issue of Cruising World about women and cruising beginning at page 46. There is a picture of Carolyn Thomas on page 48. She and her husband Curt owned a CD 25D (Yolo) which is one of the three CD 25Ds I looked at that I stupidly did not buy. Dean Abramson's CD 25D was also one of the three. Although the article references Yolo, Carolyn explained to me that they were selling because they could not fit all the stuff on board they needed for an extended circumnavigation. I think they were looking at sailboats in the 30'-36' range.

Anyway, two references to Cape Dory sailboats in one issue of Cruising World. Not bad.

[M. R. Bober]

FWIW, I used the Interlux barrier system on RESPITE a few years ago. It was a lot of hard work (my ancient back, neck, and shoulders remember it well) performed under an exacting time schedule for each coat.

Before the application of the barrier coast, there would be a few blisters to repair at each haul out. Now,after the application, there are still a few blisters to repair. Perhaps they are smaller and fewer in number. Perhaps not?

Mitchell Bober
Sunny Lancaster (where every Friday is a Good Friday), VA

[Gary H]

For whatever it is worth - I stripped and sanded the hull of my Ty last Spring. I then applied a Petit primer and Hydrocoat bottom paint. it came out of the water in the Fall in perfect condition - no blisters, no peeling.

[Steve Laume]

I hand scraped and sanded my boat's bottom down the first year I had her. She had no blisters after being hauled every other year for the past four years. I figured I would do right by her and barrier coat the bottom. It gets right back to not fixing what isn't broken. When I hauled a year latter I had a bunch of very tiny blisters UNDER THE barrier COAT! They didn't present much of a problem to sand through, dry out and repaint but what did I gain? I would never barrier coat another boat unless it had major problems. If you have her striped and go with an ablative paint you will never have too much bottom paint to remove if for some reason your hull suddenly NEEDS a barrier coating. I say, save your time and money for better causes unless you have a very specific problem you are trying to correct. Our boats are generally not prone to blister, Steve.

[aja]

I'm seen blisters pop right through barrier coatings, within one or two seasons. Once you have it done you pretty much have to live with it and become a believer.
Of course, RHM or most other marinas are going to encourage the coating. They make money on that stuff.

I would only barrier coat a hull that is in very bad shape.

[Joe Ruelle]

I hand scraped the bottom of my CD-25 the summer of 2006. It then wintered under a tarp and in spring of 2007 I sanded it and wiped it down with acetone. Then applied 2 coats of Petit Hydrocoat Alabative Antifouling. I didn't use a primer like Gary H. did when he did his bottom. There were no blisters visable before painting the bottom or after a season in the water. I am very happy with the results.

till later, Joe

[Maine Sail]

I'm seen blisters pop right through barrier coatings, within one or two seasons.

If you did this was an improperly dried hull and it happens all the time with boats from warmer climes who short haul for work. People expect to haul, strip, barrier coat and re-launch in less than two weeks and it WON'T dry in two weeks!!

Once you have it done you pretty much have to live with it and become a believer.

I'd be curious to know what "live with it" means? Just like VE or PE gel coat it can be sanded, faired and re-finished..

Of course, RHM or most other marinas are going to encourage the coating. They make money on that stuff.

Let's see, Hinckley, Morris, Lyman Morse, Robinhood and many other top quality Maine yards, who put their NAMES on boats, do more than make money on it. They bet their reputations on the past and future reliability and longevity of the brand for continued success and a stellar reputation!

How often do you hear of a Hinckley with blisters? Sure it happens but Hinckley was one of the first builders to begin barrier coating older hulls and also made the move to VE resins before many others did. All their older boats are a PE resin and PE gel but most have been barrier coated by now...

My boat yard in Yarmouth, Maine does NOT build boats but is VERY conscious of the quality of their work and their reputation. They WILL NOT barrier coat any boat until the hull is dry enough. They won't even do a barrier coat job out side!

I've personally done three barrier coat jobs and by spring in the NE the hull is always dry enough and yes I do own my own moisture meter and check it all over bellow the waterline first not just spot checks.

The neigh sayers of barrier coating have given it a bad rap because of a small sect of idiot boatyard owners and employees who, unfortunately, don't read or comprehend directions..!!

I would never NOT barrier coat after a soda blast! Take a micro scope to your hull and look very, very closely at the surface because the water certainly will!!!!

The importance of having a moisture-free hull cannot be overemphasized. The drier the laminate, the lighter the hull,
the better the performance and longer the gelcoat life. If a barrier coat is applied over a wet hull, it will trap moisture in the laminate and blistering and damage will only continue. Only when you are convinced that the hull is dry (read; moisture meter) should you proceed with a barrier coat application. Allow the hull to dry as long is it is possible. A saturated hull may require three months or longer to dry but most hulls in the NE are not saturated unless osmotic blistering is visible...

In areas where boats are stored out of water during the off-season, complete the stripping of old paint and surface preparation when the boat is hauled. Apply barrier coat product prior to spring launch. This way the hull will have a a nice long drying cycle.

[M. R. Bober]

The nay sayers of barrier coating have given it a bad rap because of a small sect of idiots who, unfortunately, don't read or comprehend directions..!!

If I were of the nature that takes offense, I guess we would duel with pistols at dawn in some leafy glade. I am not. Of course, I would not refer to an unknown group as a "small sect of idiots...," but that's just me.

As a personal matter, insults that are posted unsigned are beneath contempt. Of course that's just my opinion. You may be an otherwise decent person. Maybe not.
Mitchell Bober
Sunny Lancaster (where small lackings of social grace are rarely noted), VA