Barnacle Saga

H

hank schneider

New member
Hey Folks
Cleaned them off finally and tested the boat today.... back to original performance - 5500 rpm and 12 mph faster (30 mph w 6 people). With barnacles it was 4800 max and 18 mph with two folks. I assume the gas mileage has improved. Now I need to redress the gel coat - has a opaque luster due to sanding. Any suggestions. Off to man o war in May and want it slick as possible.
Hank
 
Hank if you plan on going to chesepeake or anywhere there is salt water and it would be a shame not to bottom paint otherwise you will be doing the gell coat all the time

Here are my thoughts you have already done the hard work Now just have a good barrier coat put on and have the bottom painted once done its real easy to do yourself about every 2 yrs or so You will be happy you did once you are enjoying your boat down in florida or wherever your adventures take you ,Unless you just want to stay in fresh water I would paint it and forget it Good luck with your decision
 
Hank, if the bottom paint is in good condition and clean, the speed reduction will be miniscule. Once it gets fouled up (with slime or dirt or anything else), you will notice a little more reduction but a lot less than if you had none and stuff was growing on the bottom. Epoxy barrier coat it and put on a good grade of bottom paint. You could probably get by with a good, hard paint rather than the ablative stuff since you will be hauling and washing the bottom pretty often.

Charlie
 
That's where I was going with my post too...if she will see any sort of sustained salt water I would add bottom paint. If you have a bare hull, I would take advantage and add epoxy barrier coat before bottom paint.

I've had good luck using Pettit Unepoxy and Unepoxy Plus hard paint. I only pull the boat out of the water maybe twice a year but I found the hard paint holds up better than the ablative if you trailer at all. It's good to pull them out now and then for a quick powerwash, it also reduces the work for winter storage.

Bottom paint will slow you down, but just a few mph at WOT. Slime or bottom growth on the other hand will cause a MAJOR reduction in performance as you very well know.
 
I'm going to open up a can of worms here, but:

It is our recomendation, since C-Dory uses Vinylester resins, that a barrier coat is not required prior to bottom painting. In fact I have seen some reports that a brrier coat makes blistering more prevelant because of trapping moisture within the lay up on older boats.

So unless you have exposed the fiberglass under the gel coat (and even then it probably wouldn't be an issue on a C-Dory) the barrier coat adds tremendously to the expense of a bottom paint job, with little additional advantage.

In talking with Andy at the factory, he agreed that the whole point of using vinylester resin is to prevent water from getting into the laminate, so adding a barrier coat was redundant.

Please note this only applies to boats that use vinylester resins in their hull lay up.
 
Hey Matt would a 06 cape cruiser be using the vinylester resins ? I wonder if the factory would know Hanks boat and mine are both 06 cape cruisers before c-dory took them over ?
 
Matt, I'm kind of curious. When we bought Journey On in '05, the C-D factory offered bottom paint, which included a barrier coat. What made them change their minds?

On boats.com I found the following: "An initial report from URI, issued in 1986, identified the principle cause of blisters as the presence of water soluble materials in the hull laminate" where URI is the Department of Chemical engineering at the University of Rhode Island. It implies that originally there is no water in the hull.

One would then assume that the barrier coat, while it wouldn't help as much, certainly wouldn't hurt. Vineylester resin is just less susceptible to osmosis, not a barrier coat as I understand it.


Matt, I'm sorry about the discussion, but blisters have always been one of my concerns. Undoubtedly with a trailerboat, it's certainly less of a concern.

Boris
 
Boris, I think discussion is a good thing, and certainly there are various ways to do things on these boats, and often they are all correct.

So if someone wants a barrier coat, we woudl certainly do it, but our experience has been that in our area, a barrier coat is not needed.

Location becomse a bit of a wild card-

My understanding, is that a boat is more likely to blister in fresh water than salt, and warm water than cold.

Which means that a lake in Arizona will be most likely to have boats with blister problems, followed by someplace like Florida or California on the Ocean, the the Great lakes and finally New England or Puget Sound being least likely to blister.

I've seen a lot of boats on Puget Sound (owned a few of them) and know that most of them do not have barrier coats, and blistering is a very small issue up here.

So we look at it from a statistical standpoint. Will the extra money you would spend on barrier coating the bottom (an extra grand or so) give any significant return on investment. Our experience in our waters says no. We could certainly make more money by barrier coating, as we would be charging for a whole bunch more labor, but we don't feel it serves our customers needs.

Now add in that many C-Dories (C-Dori?) live on trailers much of the time, so they never get the chance to become saturated like a boat that is moored in the water year round, and we think it makes even less sense to barrier coat it.

Boat yards in warmer climes may see different statistics than we do. Which might be why the factory was barrier coating on factory installed bottom paint, to take into account different areas that owners live in. It could also have been a way to get the price up high enough that buyers would opt to do it locally, as bottom painting is a messy, thankless task.

In any event, I think the discussion is a healthy one, and offer what insight we have from our experience. I'd be curious what Marc from Wefings does, as his climate is very different than ours.
 
Matt,

Your answer certainly makes the good point that the boating locale affects blistering propensity with less dense (fresh) water and higher temperatures increasing the blistering rate.

I did find a reference, from the aforementioned University of Rhode Island where they go through quite a discussion of the causes of hull blistering. It's down to the chemical reaction level, and beyond me. However, after going through the report The Causes of Boat Hull Blistering I would wonder why anyone would NOT seal their hull if they're going to leave it in the water for any time.

However, we had a sailboat that was in the water from Alaska (cold) to Tahiti (hot) and after 10 years only had one small blister. So there you go.

Thanks for your answer,

Boris
 
If I were bottom painting I would absolutely epoxy barrier coat. C-Dory hulls DO blister. I have seen it on more than one occasion. It is true that our boats are made with good quality materials by folks who care, but they can and do blister if left in the water too long.

Just my two cents,

Randy
 
Matt, Do you mean that a layer of vinly ester resin is used, or that only vinly ester resin is used instead of polyester resin?

I would like to see the reference that you have which shows increasing blistering of a boat with vinly ester resin, which had epoxy resin coating if you would.

Vinyl ester resin is less permiable to water than is polyester resin, but epoxy resin(especially those specifically formulated for bottom protection) are far less permiable to water than either vinly ester or polyester resins.

For a time 3 m was offering a vinyl ester resin as a "cure" for blistering. That product was removed from the market--and I saw some boats which had recurrent blistering. That is not to say that vinly ester resin does not help prevent blistering--but there are also many documented cases of boats laminated with vinly ester resin which have blistered.

It is very foolish to apply any bottom coating on a hull which is not dry--be it vinyl ester or epoxy resin.

I have been following osmosis and blistering for over 40 years--and have examined many boats (both in the US and Europe) which severe blistering. Some boats have no blistering--and some--like the uniflites and Valients of the late 70's all had blisters. There are many complex factors.

yes, fresh water is more likely, to have blistering, but more boats which form blisters are in salt water. Yes, warm water is much more likely to have blistering--heat speeds up any chemical reaction.

Yes a few C Dories have had blistering, and some have had gel coat problems. I recommend if one is going to put on bottom paint--no matter if trailered or not--that epoxy be applied. It is reasonably easy to do before the first coat of bottom paint. It becomes very very expensive to put on epoxy if the bottom paint is already present--and there is always a risk of osmosis/blistering, even with vinyl ester resin. Certainly a boat which is always trailered and never stay in the water more than a few months, is very unlikely to develope blisters (assuming that the bilge is kept dry during the off season).

I have also seen boat with no blistering for 20 years--all of a sudden develope visiable blisters. So just being free of blisters for a few years is no guarantee. The repair of a boat with blisters is extremely expensive. I have also seen several boats which were destroyed because of blistering (that is that there were holes in the hull--rare, but it happens)
 
Useful information but now I'm confused even more. I just bought epoxy sealer but think I may pass on it. In the future the boat will be in the water for a week to 10 days at a time (if I'm lucky). I have a clean hull at this point with an opaque (sp) surface from sanding with 100 grit to remove the little circles left from scraping.
Since the boat will not be staying in the water are there other options?
Can I recoat with Vinylester resins? If not - any recommendations on a bottom paint product for a trailed boat.
The boat is blocked up on the trailer so I'm doing something so I can go fishing.
Barnacle Advice - soak before scraping. The boat was in fresh water for 2 days before I blocked the trailer and pulled her out. The remaining barnacles scraped off like butter compared to working with them dry.
 
Hank, I don't understand your thought process..... If I read correctly, you're in North Carolina where the water is warm, you boat in fresh water, your hull is clean, you've got the epoxy, a lot of people are saying to coat the boat and you're saying "maybe not?"

Are you kidding us?

Boris
 
Hey Boris
Not kidding - just confused - I am going to put something on the bottom just to address the opaque surface - I was trying to figure out the best option.
Hank
 
For Hank-

If you already have the sealer, and you plan on doing the work yourself anyway- apply it. Just be sure to allow the hull to dry out. Wiping down with acetone can help.

Thataway-

My understanding is that Vinylester resin is used in the hull layup instead of polyester resin because it is more water resistant.

I should have been more clear that the barrier coat application had caused blistering on older hulls where moisture was trapped in the hull, so these were probably not vinylester built boats. This should not be an issue on a new boat.


:arrow:
I can speak best about what we see here on the Puget Sound. I have had numerous boats myself, and of course seen scads of others.

My 1986 Carver 32 Aft Cabin at 20 years of age had 5 blisters on it's bottom. All of them over an inch in diameter, so they were ground out, filled and painted over. No barrier coat on that boat and no vinylester resin. I don't consider that this boat had a blister problem. At next haul out, no sign of new blisters and no reblistering.

My 1985 Bayliner 2560 had a couple of small blisters on it's bottom. So small (less than the size of a quarter) I didn't do anything with them at haulout. Again, this boat does not have a blister problem.

My 1971 Chris Craft 35, which spent the first 30 years of it's life in New Orleans had no blisters when I bought it, and no sign or indication that it had been stripped and barrier coated. We even did some hull work to it, and in grinding down found no evidence of barrier coat.

So I mentioned that we don't, as a rule, apply barrier coats, because we don't see blistering problems in these waters. In the last three years we have not barrier coated any of the new fiberglass boats we have sold, nor any of the boats we have had come in for bottom paint.

The yards near us don't apply barrier coat nor recommend it, unless the boat owner requests it.

That's just the conditions that exist where we are. We just don't see many boats with blister problems, they are the rare exception (excluding Uniflites where there is a known resin issue).

So statistically, for our customers, we would not recommend barrier coats because the chances of having a problem are very small. And even one or two small blisters can be repaired down the road less expensively than what the barrier coat costs.

As always, an owner needs to weigh the various factors that affect their particular circumstances, and make the best decision for their needs. I just bring up the other side of the coin, because I think it is not always in the owners best interest to barrier coat.
 
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