Wet Slip (bottom paint?)

[delevi]

I'm entertaining an idea and wanted to get some feedback. I'm thinking about getting a slip and keeping the boat on the water 15-20 days out of the month, and hauling out; keeping it on the trailer the rest of the time. This would be about 9 months of the year and the three months when I wouldn't be using the boat much, I would keep it on the trailer full time. Can I get away with this without bottom painting or would marine growth still have its way with my hull?

Leon

[Bobby T.-26X #4767]

the way to do it is to use a "bladder".
IIRC, they're about $1500-2000 and can last over 3 years.
the premise is that once you arrive into your slip, you pull the bladder closed around your rear end, add some fresh water, and have a couple of chlorine floats swimming around.
makes the water "brackish" at the very least.
if done properly, no more than a soft layer of moss will form that can be scrubbed with a soft brush.
a Mac X owner in Oceanside Harbor that i know uses one and it works great!

Bottom Liner




Bob T.
"DaBob"
'02X w/ '04 90-TLDI & '06 2.5-Suzuki

[Night Sailor]

A chlorinated pool might retard marine growth and keep oil stains off the bootstripe but offers no protection against osmotic blistering of the gelcoat. Perhaps, in a warm, dry climate, the 10 days a month the boat is out of the water might give the gelcoat time to dry out, so blisters would not form. Then again, maybe not. Bottom paints are said to reduce blister formation even without an expoxy barrier coat.

Since you have an unblistered, unslimed bottom to start with, having a yard apply an expoxy barrier coat and a good multiseason, trailerable, antislime paint like Interlux Microm Extra would cost about the same and last as long as the bladder, with more assurance of blister protection.

[wtelliott]

I can't imagine spending that kind of $$$. I sanded, epoxied, and bottom coated my X for a fraction of that last year. This is the second year in a slip in Lake Superior and it still looks great.
If people are actually getting that kind of money to bottom coat boats, I gotta get into that line of business.
Besides, I'M CHEAP.

[Bobby T.-26X #4767]

Good Article about Osmotic Blistering

"Now this brings us to another misconception- Osmotic blistering is more likely to occur in saltwater. Actually, fresh water is less dense than saltwater and therefore the potential for the osmotic process to occur is greater in fresh water than salt. Higher water temperatures also contribute to the process."

Continuous Wave
General articles on Boston Whaler Boats and closely related topics.
posted 06-19-2005 02:22 PM ET (US)
--------------------------------------------------------------------------------
A blister can form in either fresh or salt water. Theory varies on the cause, from imperfect or old catalyst in the gelcoat mix or minor voids beneath the gelcoat, to small imperfections or scratches in the hull.
Yards around SF bay charge about $1200-1500 to haul, prep, barrier prime, and bottom paint a 23 ft whaler (including materials). As JohnJ80 mentioned, this is cheaper than the cost of his repair. The peace of mind is immeasurable.


all that i can tell you is that the MacX in Oceanside has been in the bladder for over 12 months (taken out on occasion) and there is no blister problem.

[Chinook]

We've always "moored" our Mac X on the trailer in the driveway when not in use, thus have never applied bottom paint. However, a couple of years ago we cruised the Atlantic Intracoastal Waterway from Virginia to Florida, in brackish to salt water. The boat was in the water continuously for about 7 weeks, in early winter with water temps mostly in the mid to high 60's if I remember right. I beached once and scrubbed what I could reach. When I pulled her from the water I had quite a biology experiment going. I spent several hours cleaning soft and harder growth. A month later we went over to the Bahamas, and were in the water for 8 weeks. I beached twice and did some scrubbing, and again, at the end of the trip had a lot of scrubbing to do. Hard work but it cleaned up fine.

I considered bottom painting before last summer's cruise up the Inside Passage to Glacier Bay. After some discussion with Blue Water Yachts I decided to forego painting. Colder water, low salt content in many areas, regularly under way were some considerations. Before leaving, I did apply a couple coats of anti fouling wax as an experiment. Along the way we developed a green skirting of algae growth near the water line, which was easy to brush off from the dinghy. At the end of the trip I was curious to see what I'd find. The bottom was blotchy with surface algae like growth, fairly easy to clean off. No barnacles at all where I used the wax. I did have some small buttons forming in places where I couldn't reach with the wax.

For the way we're using the boat right now, mostly in the Pacific Northwest, I'm happy with the decision to not paint. I'll have to do some soul searching when we return to the Bahamas or explore the Sea of Cortez. Maybe the wax would be sufficiently effective in those waters for up to 8 weeks or so.

[Night Sailor]

Apparently folks have good luck with wax in colder waters. Based on some forums advice I only heavily waxed my boat's pristine and flawless bottom before putting in a lake for a year. Even though I scrubbed every two weeks with Dri Diver, when I pull the boat this spring for inspection, the growth was so thick not all of it could be removed with a 3000 psi pressure washer or even a steel scraper. And, the bottom had multitudes of tiny blisters for the first time. $1400 later, I have a pretty black bottom job and some assurance that it will retared blistering based on other local boats both power and sail
After some research it appears that not only is fouling by marine organizms greater in warmer water, but blistering can be also. The water in my lake reaches up to 91 degrees in August, where the typical dailly high air temp is in triple digits. During previous cruises in cooler waters for up to three weeks duration, no slime buildup or blistering occured with just a wax coating. YMMV.

[James V]

On my trips of 20+ days on the boat I have seen little growth on the bottom. A going over with a soft brush was all that was needed.

I would check with the other boaters in your area. For now, the wax with the additive should do you. After you pull the boat out a few times you will see if you need more. Not to worried about blisters, the boat should dry out when on the trailer.

If your boating in Florida for a few months, I would say different.

[Frank C]

Unless I've misunderstood lots of reading about this problem, periodically trailering the boat won't prevent blisters by allowing it to "dry out." It prevents blistering by removing the water pressure caused by floating in the water. AFTER blistering has occurred, THEN the hull requires a lengthy time on the trailer to dry out the fiberglass. But that assumes you've already suffered blistering, and the blistered gelcoat has been sanded off the hull to expose the now-waterlogged layup.

It's unclear whether differences in blistering time and experiences are due to differing water temps, salt vs sweet, differing critters and slime ... OR just differences in the layup of individual hulls. But for every anecdote about a hull that survived a year on wax only, there's another anecdote about a hull that blistered with the same treatment (latest example right here, by NS). This topic deserves a poll, but I doubt the forum software can provide a poll that's discrete enough.

By reading in many different sources, my conclusion is that blisters are caused by constant water pressure, applied over some indeterminately lengthy time. Eventually the water permeates the gelcoat into tiny voids between gelcoat and layup. Opinions vary on whether the blister results from a water-induced chemical reaction with fiberglass (under the gelcoat), but water, physically pushed thru the gelcoat, is thought to be the primary force. Vinylester resin supposedly reduces the chance of blistering, either by eliminating those voids or eliminating the chemical reaction. But vinylester resin is costly and not available from Roger's factory.

The fact that choice of resin is demonstrated to change the prospect of blisters ... seems to infer that differences among the critters or the waters do not correlate with likelihood of blistering. Rather, this "lack of blistering" seems to correlate with the resin, FRP, or the gelcoating process. A boat-builder using vinylester layup seems to be blister-free regardless of the water conditions. But then too, rarely are such boats left completely uncoated. Many builders apply epoxy coating right at the factory.

Anecdotal evidence seems to indicate that blistering does not occur in just 4 weeks, or even 8 weeks ... but I expect the actual "time to disaster" varies with the layup quality of each individual hull. I agree that it "seems logical" to assume that there is a time continuum during which microscopic blisters must be forming ... but does trailering actually interrupt that process by drying them out ??

Seems extremely unlikely to me ... if it takes months to force water thru the gelcoat, could that same tiny amount of water simply evaporate back thru the gelcoat once on the trailer? We need a scientist here .... Catigale, is this just a guessing game?

Blistering is so costly to remediate that I'd not want to risk it. Blisters are likely, or destined (?) to eventually occur on a floating hull. Their cure costs more than the initial coating, so it seems a no-brainer to coat any hull that will be floating for more than __( how many?)__ weeks. (For me, that number is 6 to 8 weeks). Would a cycle like 2 weeks IN, then 2 weeks OUT, eliminate the problem? I think the monthly clean-up might cancel the recreational benefits, for me.

Would floating within a bladder solve the problem? .. slime problem, yes .. for blistering, I doubt it. But the bladder DOES sound like a potential half-way step, with an epoxy barrier for the blisters plus the bladder instead of antifoul paint. But, exactly what treatment might be environmentally acceptable within the bladder?

I've seen here, for first time, that some in the industry dispute whether an epoxy barrier can actually prevent blisters. Previously, I'd always understood that epoxy is a guaranteed barrier to the pressure-induced permeation of gelcoat. It sounds right, since epoxy is widely used to protect other materials, like concrete - so I'm dismayed to see that debate.

I would not put my boat in a slip without at least a barrier coat. Absent antifouling coat, I'd want frequent time-outs for cleaning slime & barnacles. And as I discovered this year during two weeks of trailer maintenance, the boat needs immediate cleaning once trailered again. I might try an anti-sliming wax instead of antifoul paint, but epoxy would be a bare minimum, for me. I might go ahead with epoxy anyhow, just to mitigate blistering risks during short-term dunkings, up to a month at a time.

EtA: sorry to see, now, that I've blathered-on even longer than usual. This is a complex problem about which I've done lots of reading, and one I'm loathe to discover on my hull. The financial risks of a poor choice are big boatBucks ... here in the SF area I'd double Nightsailor's $1,400, about $3,000 for remediation and paint. There's no easy answer, since the penalties of full bottom paint (in both cost and speed) are so significant.

[Terry]

I wet slip for 4-6 months in the Pacific Nortwest, this is my third season, 3 months first year, 4 monthe second year, almost 6 months this year by the end of September. I am right at the 49th parallel and the water rarely exceeds 60 degrees, usually much colder. I have been experimenting with the Aurora VS721 bottom wax this year which claims to retard marine growth and prevent blistering. Well, it works to some degree on the growth, but I still have a big job of cleaning the hull every 6 weeks, but the barnacles/muscles etc. seem to blast off fairly easy with a 1600 psi washer. I then scrub it and re-apply a couple more coats of VS721, I have gone through this process twice so far this season and a third is soon due. Without the bottom paint you still get the growth and I can personnally attest to the major effort it is to keep it clean. (It's bullshit) but I endure anyway.
As for blisters, so far so good, once I get that hull shined back up there is not so much as a microscopic hint of blisters, I feel over every square inch and inspect it closely. It takes me a week to clean it all up again so perhaps it gets to dry out a bit. After reading Frank's input I get the feeling I am playing Russian Roulette but I still remember an Interlux dealer telling me epoxy is not required unless the boat will be slipped for years not months. Yet, as Frank pointed out there are anecdotes for both sides so perhaps some of us may learn the hard way or with any luck not at all. I think we do need a scientist to weigh in all the variables for the different conditions that we experience. As for Leon's original question, the answer is (from my experience) absolutely yes, you can get away without the bottom paint, but you absolutely cannot get away without sweating it out on your back and cleaning off that hull every time you pull it out onto the trailer, the marine growth will have its' own way eventually.
I am also very interested in some of the details of Chinooks' discussion with BWY on the topic, exactly what did they say about it.
Here's another uninormed question that may sound stupid but here goes: Why would there not be a combination epoxy coating with the anti-fouling mixed in with it so it can be applied all in one?
Sure hope I never fall victim to blistering, and yes I know an ounce of prevention is worth a pound of cure, perhaps I will rethink my position on it after reading more input.

[delevi]

It almost sounds like the effort in hull cleaning takes away from the luxury of avoiding launch i.e. having the wet slip to begin with. I sure would hate to paint the bottom and endure the anual cost of $1500 or so, along with the cost of a slower boat, as Frank points out. Please keep the posts coming. It's nice to know what everyone's expeirence is in this regared. For the two years I had my boat, it's been on the trailer, mast up, launched every time I use it, which is frequent. I do get a guest slip at my marina for a day or two, when I know I'll be using the boat for the weekend. The longest trip so far for me has been 5 days. No growth. Just a bit of green slime which came off quite easily with the hose.

Leon

[Frank C]

... but I still have a big job of cleaning the hull every 6 weeks,

AND
... I then scrub it and re-apply a couple more coats of VS721, I have gone through this process twice so far this season and a third is soon due.

AND
... Without the bottom paint you still get the growth and I can personnally attest to the major effort it is to keep it clean. (It's bullshit) but I endure anyway.

AND
... It takes me a week to clean it all up again

AND
... you absolutely cannot get away without sweating it out on your back and cleaning off that hull every time you pull it out onto the trailer,

... yes I know an ounce of prevention is worth a pound of cure, perhaps I will rethink my position

Well, you convinced me, Terry! ... at only $1500, an epoxy barrier coat is CHEAP!
Maybe the slime tent is cheap too at $3000 ... I still don't want AF paint on the hull,
but I can't imagine cleaning that hull 3 times per season, eiher ... hmmmm

[Terry]

Frank, you are hillarious!!
You bring tears to my laughter
I don't realize what I sound like until someone like you extrapolates out the funnies and lines them up. I must say it is refreshing to be able to laugh at myself. Curious though, why this comment:

I still don't want AF paint on the hull,

I also sense that BWY is cold to this idea too, I don't see the sense in doing just the epoxy and not the AF paint, it is the AF paint that would save me sweating it out on my back, if I am going to do either one I would think I should do both. It is a huge effort keeping marine growth off. The reason I have not done it yet is because another Mac owner advised me that if I have not already bottom painted that I shouldn't because it also requires bi-annual maintenance, it has to be repainted regularly, so I am dammed if I do and dammed if I don't.

[Bobby T.-26X #4767]

epoxy barrier and bladder.
no blisters...clean...fast!
you will be the envy of Mac owners around the Bay.

[Frank C]

I was actually targeting your perserverence, not poking fun. I guess my 26X is still on the trailer because old-timers on this board always said I'd regret AF paint (Steve K, in particular).
Bottom paint's a bit like a marriage (edited to Add yet more similarities):

• It's an expensive long term commitment ...
• It increases weight;
• It reduces reduces speed;
• Requires an initiation fee (like wedding costs you pay yourself);
• Requires immediate doubling of rent;
• Reduces recurring maintenance, but requires periodic major maintenance;
• The sailing relationship becomes more frequent, relaxed, spontaneous;
• (Sailing off the trailer is like dinner & dancing before the sail);
• and the divorce is very costly too.

I'm considering the epoxy coat because I'm averse to the headache of blisters, I think it may incur no speed penalty, and it might make your occasional cleanup easier. A boat lift would obviate both epoxy and AF, but the slime tent only eliminates AF.