Gelcoat Issue Mac 26M (is it a lemon?)

[Andrey-314]

I have a 2008 hull launched in 2009 coated by epoxy primer (not a barrier epoxy as manual do not mention it) and hull paint as advised per manual (professionaly made). First season no blisters, have applied this spring two layers of same bottom antifouling paint. In August still no blisters (layout for engine maintenance), later in October -just millions below waterline. It's really a pity to made all preventive measures an get a blistering hull in result. I like my boat and Roger did great project actually. But Customer should be informed properly and select an option - factory guarantee from blistering either from dealer for additional bucks. And for sure Customer should not be leaved without any support alone with his blistering hull AT LEAST during guarantee period. If blisters is not common issue for it should be considered under guarantee once you are in line with official manual. Otherwice looks like a cheat.

[Highlander]

Well my boat was slipped in the water this yr for over 9 wks , I usualy have it out of the water every three wks or so to do mods & clean it then ! not this yr though gave it a fast clean before I trl up to PQ & it looked good but I do plan on doing a bottom expoxy & anti-fuol paint job next Spring before she goes in the water , hopefully this spring coming I will be able to finnish off all the mods that require the boat to be @ home , after that any other mods I have planned hopefully can be done while the boat is @ her slip

J

[Andrey-314]

Have a lot of discussions with yacht architect last weekend. Actually looks like gelcoat quality is not a real reason of blisters. Water can penetrate to hull fiberglass from inside ballast tank causing osmosis blistering in outside gelcoat. Based on my observation all blisters are located in the ballast tanks/pipes areas. This is the whorst scenario - even re-gelcoating / barrier paining outside the hull will not help to eliminate blistering cause. My question is anybody here having this problem in the past have had re-occurance of blisters after application of barrier paint/other corrective measures? Or the best solution is boat repair and immediate sale? I don't like such development. Please advise any comments, thanking in advance.

[Terry]

From what I've read, it seems they are more prevalent in fresh water than salt. I guess it's less dense and gets through the gelcoat easier. Also, from the numerous posts, the Mac seems to have a crappy hull gelcoat. After 1 season in fresh water, my '08 Mac had blisters. How serious a problem depends on how many and how deep they are. I let my Mac dry out over the winter and many of them subsided but there are still quite a few left. The next season I applied a coat of Aura bottom wax and no new blisters. In retrospect, I wish I had done this before any blisters, it might have given enough of a barrier to protect it.

The "fix" if you choose to is to sand them and "pop" the water out of them, dry it out and put an epoxy coat over it. I'm not sure how that would look essentially painting the bottom and possibly creating a rougher surface than the smooth gelcoat with some blisters.

Some people recommend an epoxy coat to protect the gelcoat, similar to the people who paved my driveway and then told me to seal coat it. I guess that's a good idea, but it seems like my gelcoat should hold up like other boats do.--Russ

If you de-wax and sand the bottom for anti-fouling paint you are essentially creating a more porous gelcoat that will enable blisters more readily. An epoxy barrier coat before the anti-fouling will seal the gelcoat bottom and help prevent blisters.
I used the interlux 2000E epoxy, 4 heavy coats and then the interlux CSC ablative antifouling.
For the first 6 years that I did not have bootom paint I waxed heavily with Aurora VS721 bottom wax several times a season and let it dry a few days each time I cleaned and re-waxed. I also hauled it to my driveway each winter and let the ballast tanks dry all winter. I still have no blisters and perhaps I may haul once a year anyway to empty the ballast and let her dry inside out. I'll wax the blue hull sides and top sides while I am at it.

M production when quality control was more stringent ...

WADR , have you ever visited the mac factory??

No, I have not visited the factory, just an assumption I made based on a belief that when a new model is introduced that any factory would be more diligent with quality standards on an introductory launch, especially during the first seasson.

[Catigale]

I didnt mean to sound so condescending...or maybe I did out of sarcasm...in any event, I apologise for that.

In my limited experience, the boat industry is far from standards of manufacturing quality of an industry like autos or other complex assembly manufacturing. The Mac line is probably most primitive in this regard, given that it is an entry level boat with a focus on price leading.

Just the way my rudder brackets are attached confirms that the most basic standards of quality control arent there.

[dca81]

Interesting comment that the blisters on some boats may be coming from osmosis thru the ballast tanks. This seems contrary to most of the input I got on blisters and my own recent experience. I purchased a used last year and it had blisters on the hull. I had the blisters removed and applied 4 coats of barrier coat and two coats of bottom paint to the hull. Then I put my boat in a slip for the entire summer, never emptied the ballast tank. When I pulled my boat this fall the bottom cleaned easily and I did not see any new blisters. Sure hope I don't start blistering again from osmosis thru the ballast tank Do I need to do something else?

[Andrey-314]

Actually my assumption based on fact stated in my previous post as I have PROTECTED bottom as recommended by manual starting from the first season. No barrier paint but a good layer of epoxy primer before antifouling paint.
As I've mentioned, first season were no blisters, at the end of second (may-october) - millions tiny blisters below waterline. Boat passed 5000 nautical miles for two seasons, at least 3000 sailing. Baltic sea region - low salt density at sea, marina located in the river with fresh water, water temperature through season vary from 10 to 25 degrees centigrade. Ballast water have been changed periodically, at least once per 2 weeks.

[dca81]

Awww, an assumption...based on conjecture of the cause of a observed outcome. I have made many assumptions, some of my ass-u-mes are good and some... not so good. Assumptions are best made by those who are experienced and have "seasoned judgement". I'm a newby to sailing, usually just seeking help, so I'm not much help, but am interested in the "seasoned judgement'" of the others on this site.

[Andrey-314]

Actually I do prefer to be wrong because otherwise it will be disaster with no solution of the problem. That's why I'm asking to advise known cases of blisters re-occurrence. Thanks a lot in advance!

[Catigale]

Using the word 'osmosis' is really not correct to describe the phenomenon here - the action in question is really water permeation of either the fiberglass (FG) (from the ballast tank) or the gelcoat (from the outside)

With thousands of Macgregors on the water, and thousands of other water ballasted sailboats out NOT blistering from the sea/fresh water being in the ballast tank all year around - I would worry more about the stray 747 landing on me in the marina.

Blistering is certainly only a cosmetic issue for a correctly 'laid up' FG boat - I can certainly say as a prospective buyer a newly painted/epoxied hull is as suspect to me as a hull with visible blisters - after all, its the devil I cant see.

So as to not offend anyone, I will state that Macgregor's manufacturing margins are geared to towards "am efficient use of materials and labour to provide the value price on the entry level market"

which can be translated build-wise as the gelcoat is probably thinner than most - and more susceptible to permeation.

Follow directions of manual and epoxy bottom coat if you are staying in the water.

[Andrey-314]

Ok, sounds good actually. I believe that blisters is a cosmetic issue only but what is the reason causing them, especially in my case, I repeat my boat was painted in accordance to manual prior launch. Materials and workmanship were professional and very good. And I'm not trying to blame product which I like, I'm simply trying to clarify why blistering appears exact on ballast tanks/pipes areas. Maybe it connected to absence of proper ventilation of fiberglass, who knows. I'm happy to hear that there no osmosis (terrible word) observed on thousands of near ballast tanks area or anywhere else but is this statement really true? Once assumption that water comes to fiberglass from ballast tanks side causing gelcoat blistering outside is true than we can expect that epoxy /barrier paint will not help and blisters will appear again. I'm happy to hear that problem is not observed so far or just not exist. Or exist but not highlighted due high re-sale rate

[Divecoz]

Just my spin , no proof.. However , I do not for now "buy " into the theory that its coming from inside out... I suspect its rather more to do, with temperature differences involving the tank area, due to the contained water??

Interesting comment that the blisters on some boats may be coming from osmosis thru the ballast tanks. This seems contrary to most of the input I got on blisters and my own recent experience. I purchased a used last year and it had blisters on the hull. I had the blisters removed and applied 4 coats of barrier coat and two coats of bottom paint to the hull. Then I put my boat in a slip for the entire summer, never emptied the ballast tank. When I pulled my boat this fall the bottom cleaned easily and I did not see any new blisters. Sure hope I don't start blistering again from osmosis thru the ballast tank Do I need to do something else?

[Andrey-314]

Well, there some pictures below describing my case. Looks like blistering have appeared in places where gelcoat is thinner:

Blisters itself looking like:

causing gelcoat damage up to laminate:

[Andrey-314]

So in my case epoxy primer (not a barrier paint) do not help to avoid blisters development. Here on the picture you can see all layers covered at the bottom:

As laminate is dry so far we can exclude version that moisture is coming from inside ballast tanks, at least at a time.

[Divecoz]

Andrey can you tell us what we are looking at, with each picture?
#1 = #4 ...... Bow, Stern what ever..
Where on these boats, are there 2 S.S. bolts installed side by side under, I presume then, under the water line??
Epoxy Primer... Sounds good . Sounds like a true Barrier Coating , but its not! Its real claim to fame is its adhesion factors . Increased adhesion to bare metal and FOR adhesion of the final coat. The final coat is the Barrier Coat... Most are now cross link compounds..