MacGregorSailors.com

Looking forward to bringing home my new Mac 26M at the end of April but was looking for some advice regarding the issue of applying a barrier coat in addition to the planned bottom paint. I was a bit surprised to read in the Mac owner's manual that a barrier coat would be needed if the boat was to be left in the water for the season.
My plan is to have it parked dockside on a finger and will have it on the lake from mid-May to mid-October.
Any thoughts regarding the need for the barrier coat and if so, any recommendations for an easy-to-apply system?

As always, thanks in advance for your great advice!

Ray

Just Roll

Yes you should bottom coat if the boat is going to stay in the water. The Macgregor may (probably will) blister(small pimples) if left in the water for an extended period of time without the protection of a barrier coat. Based on posts on this site I have concluded this is most probably the result of an economically efficient (cheap) method used at the factory for applying the gel coat. About 3 years ago I purchased an 04 . The boat had obviously sat in the water for a prolonged period and the bottom was covered with a dry crusted algae growth (boat was out of water several months before my purchase). Once I cleaned the growth off the bottom I saw small pimples/bubbles (blisters) in several areas. I had the blisters removed at a cost just under $2K. Since I planned to slip my boat for the season I decided I should apply a barrier coat to avoid future blisters and anti-fouling paint to keep the algae growth away. Quotes (2) for barrier coat and paint were in the $2,300-2,500 range.
So I decided I could do this. I applied 4 layers of barrier coat using Interlux 2000E. The bottom 2 coats are gray and top 2 coats are white. This way I know if I ever sand or scrape the bottom and see gray I am close to the hull. I then applied 2 coats of Interlux VC-17 antifouling paint. The costs of materals/supplies was about $500 and I applied it with a roller. The boat has been slipped from the end of May to mid October the past 2 seasons and I have had no additional blisters, or significant algae growth. I have been very pleased with the results so far. At season end I simply clean the bottom with my car wash brush and soap.

Great post dca81..I will add that dca81 and no less than about 90% trailer our boats home , when need be .....No lot storage cost.... No fork lift in and out or porta-crane cost..I added a couple links more fellows might want to watch ( in the repair and mods section ) and you new owners should have received For Free ( I did from Bills Boats 4 Sale) a 55 min DVD when you bought your boat.. These Are Great Boats..dca81 saved around $2000!! for doing it himself and now no doubt knows how much he could have saved doing the pimple repair or even just letting it dry out for the winter and barrier coating it as it was .. IMHO The costly expense was not needed ..

dca81 wrote:Yes you should bottom coat if the boat is going to stay in the water. The Macgregor may (probably will) blister(small pimples) if left in the water for an extended period of time without the protection of a barrier coat. Based on posts on this site I have concluded this is most probably the result of an economically efficient (cheap) method used at the factory for applying the gel coat. About 3 years ago I purchased an 04 . The boat had obviously sat in the water for a prolonged period and the bottom was covered with a dry crusted algae growth (boat was out of water several months before my purchase). Once I cleaned the growth off the bottom I saw small pimples/bubbles (blisters) in several areas. I had the blisters removed at a cost just under $2K. Since I planned to slip my boat for the season I decided I should apply a barrier coat to avoid future blisters and anti-fouling paint to keep the algae growth away. Quotes (2) for barrier coat and paint were in the $2,300-2,500 range.
So I decided I could do this. I applied 4 layers of barrier coat using Interlux 2000E. The bottom 2 coats are gray and top 2 coats are white. This way I know if I ever sand or scrape the bottom and see gray I am close to the hull. I then applied 2 coats of Interlux VC-17 antifouling paint. The costs of materals/supplies was about $500 and I applied it with a roller. The boat has been slipped from the end of May to mid October the past 2 seasons and I have had no additional blisters, or significant algae growth. I have been very pleased with the results so far. At season end I simply clean the bottom with my car wash brush and soap.

Okay, here's my question. Can I repaint my barrier coat over my existing barrier coat once I remove the antifouling or do I have to remove all the old barrier coat , which seems to still be adhering well ?
Q1

The best idea is to apply like over like. If its on the bottom and gripping well, lightly sand, wash, dry and recoat.
Make sure ALL areas are good. The barrier coat my dealer put on was pimpling off the hull in areas although the hull underneath was fine. This after only seven months in the water. All bottom paint must be sanded off, of course.


I often fantasize about hitting the lottery, sending Roger on vacation and renting his molds to build a foam core and vinyl ester resin 26 M. No more blisters. Strong stiff boat. Probably lighter.

Ixneigh

Ixneigh wrote:I often fantasize about hitting the lottery, sending Roger on vacation and renting his molds to build a foam core and vinyl ester resin 26 M. No more blisters. Strong stiff boat. Probably lighter.

Ixneigh

have to be careful about foam core. The thickness is critical to it's sheer strength--too thin or too thick and it looses it's sheer strength which is where it's structural integrity comes from. Also, any holes or water penetration into the foam can cause it to decompose, and in those spots where it gets mushy it looses all strength as well. It can be done right, but it's difficult to engineer, very hard to repair correctly if it's been penetrated, and expensive if you're using a marine grade closed-cell foam that can actually stand up to seawater penetrations.

I like the idea of it, but the practice is not nearly as simple as woven roving fiberglass and resin.

If I bought MacGregor's factory, here's what I'd do:

1. Move it to AZ or Rosarito to lift the CA VOC emission limits
2. Go to a stock Carbon Fiber mast and boom.
3. Ball-valve on the mast gate and vent-tube to chainlocker mod, so the ballast tank automatically floods when the boat is in the water. To empty ballast on the water you have to screw down the ball valve in the open position deliberately, and then when its empty screw it down into the closed position to keep the ballast tanke empty. Purpose is to make the boat inherently safe even for forgetful people.
4. Put the mast on a 5' foot high "A" frame "tabernacle". Imagine two 5' aluminum poles ala the spreaders that are in the position of the baby stays (and replace them). they're connected to the mast via a similar mechanism as the spreaders, and they can pivot at their base from forward to vertical (but not beyond vertical. When you unbolt the mast foot, the mast lowers to the mast bracket while the A-frame folds forward towards the pulpit to place the mast foot where it belongs. The mast is managed and cannot move except into it's two proper positions. It won't, for example, be able to slide off if it's not pinned at the pulpit. The purpose of all of this is so that you can...
5. Connect the mast foot to the daggerboard via a stainless cable and...
6. Add a 400 lb. daggerboard.

This system puts the mast and daggerboard in a balanced system. When the mast goes up, the daggerboard goes down, and when the daggerboard goes down, the mast goes up. In equilibrium, the mast waves around at a 60 angle upright and the daggerboard is 3' down. You have to give it 10 to 20 lbs. of "push" to get it fully upright or fully down. Then you pin the mast in place (mast-up) or daggerboard in place (mast-down) to take all the tension out of the system.

Provides an inherently balanced and mechanically simple mast raising mechanism with minimal additional complexity, the stability of a heavy daggerboard (still would have to be designed to break away, but would then remain connected by the cable so no lost) and mast falls become impossible (although it'll drop far enough to scare you).

If you unbolted the mast from the pulpit and then unbolted daggerboard and allowed it to drop, the falling daggerboard would pull the mast foot aft, causing the a-frame to pop up to the upright position, and would then begin pulling the mast foot down, raising the mast to about the 60 degree position, where it goes to equilibrium.

When the mast is up, if you unbolted the foot and let the mast fall, it falls to about 30 degrees, and then the weight of the daggerboard bobs it up and down until it stabilizes at 60. The A frame would not move in this scenario.

In either case, it's inherently safe and (with spreaders removed) much simpler than the current mast raising technique (which isn't bad by any means). Would be better for people with less strength as well.

You lose the ability to manage daggerboard depth (unless you want to add an optional 12v pulley to raise it when the mast is pinned) and you have to raise the mast on the water instead of on the hard. But the ease of raising and lowering should compensate for that.

Maybe I'd make it an option.

Matt

We went with a barrier coat and it is less than $150 for the paint (Sea Hawk) and once the bottom was ready only took a couple hours as the Sea Hawk goes on much thicker than other barrier paints and only requires 2 coats. I was able to put on 2 coats, plus 3 coats of bottom paint in one long day. All the info is here ...

http://purplesagetradingpost.com/sumner ... de-39.html

Québec 1 wrote:Okay, here's my question. Can I repaint my barrier coat over my existing barrier coat once I remove the antifouling or do I have to remove all the old barrier coat , which seems to still be adhering well ?
Q1

If the barrier paint is ok, why do you want to put on more? If you need to and remove the bottom paint and go into the barrier paint with an 80 grit I would think you would be fine. I'd be sure to clean before and after sanding with a wax/grease remover,

Sum

Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

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Welcome Ray!

I’m not familiar your product, Sumner, but I will say to you Ray that Sumner is held in high regard and respected by others (as well as me!) on this forum.

I used the following on my boat as suggested by my dealer with excellent results so far. I used 1 gallon + 1 quart of Interlux Interprotect 2000E for the barrier coat. Then 2 quarts Micron CSC black, then 2 quarts CSC blue for the antifoul coating. I don’t believe (I could be wrong) that Interprotect can be used alone without something on top of it. Applying these above amounts will give you the recommended coating thickness on a Mac M, which, because it’s epoxy, is more important than the actual number of coats applied. It’s easy to accurately confirm the mil thickness by using a micrometer on the masking tape. Or a vernier caliper if you’re good with it. I think I did it in 7 or 8 coats.

Use special solvent rollers and mask the edges. Do the daggerboard and inside the daggerboard trunk as far as you can reach. Contrary to advice I was given, the rudders don’t need it, they’ll be out of the water most of the time. Better to have that paint on the hull.

This is a durable ablative antifoul coating that can also handle on-off trailer cycling. Most of the product reviews I’ve seen don’t include fresh-water testing, so there is not a lot of long-term independent testing of these products out there. Practical Sailor tests out of Sarasota, Fl, and this product tested well there (salt water), and is also for fresh water. You’ll probably get a mixture of fresh and salt water sailing from Dorval, I presume? Unless you plan on not sailing too far east?

One under-reported (or never-reported) benefit of having a higher horsepower engine is that it makes you sail faster, even when the engine is off. Yes. It’s true. (ps now you’ve been warned -I love to make ostensibly “wild” claims that are true. ) How so then?

It works this magic by cleaning your hull off at the higher speeds. A good run at high speed will strip the growth off your hull, if you have antifoul coating applied. This would not happen as effectively, if at all, with anything “inferior” to our Macs, because they can’t go so fast. So your Mac could easily be faster than other sailboats under sail in the marina near the end of the season if you apply an anti-foul coating and they don’t, and/or don’t clean their hulls.

It’s a good maintenance practice to take your boat for a full throttle run every couple of weeks for this and other reasons.

You will also need an orbital or similar sander and all the solvents and surface prep washes suggested by the manufacturer, who will provide you with literature and details on how to properly do the job. The new gelcoat sands down surprisingly fast, (to remove the gloss) and doesn’t clog the sandpaper, so you won’t need much of it. (I bought, I think 50 sheets, and used maybe 4 of them).

That will be around $600+ for materials. Plus sweat. If you’re handy, and do it yourself, it is fairly easy to do at least as good a job as you would get if you paid someone the estimated $2400 it would cost for them to do it. That price is why most boaters (power and sail, who don't trailer) don’t do it, and take the gamble with blisters. It represents a fair percentage of the cost of owning a polyester fiberglass boat, but is not “showy”, so that money can get spent on frilly extras instead, if at all.

You can access the hull yourself from the trailer in your own driveway using the trailer’s own jack, and roll the trailer back and forth as you move along it. My biggest piece of advice is - don't be in a hurry to finish. It's all really straight forward, and it will go smoothly if you do it carefully and take your time.

Have fun! -Brian.

Hey Q1 – For touch-ups on a cleaned hull, I would expect a solvent wash and a light scuff sanding would be all you would need for prep. I expect the “soapy” like surface of my Micron to clean up easily and take on a new coat, but I haven’t tried it yet.

For me its a touch up job as the application of the last barrier coat was top notch and seems to be really thick. I will be using a new anti fouling (Natural Marine Foul Release Spray) that is liquid, clear and goes on thin.

http://www.canadiantire.ca/AST/browse/5 ... ?locale=en
Q1

Hey Q1!

Looks interesting- haven’t seen that one before, they don’t tell you much about it, and I couldn’t find a white paper online about it. It must be a new product to Canadian Tire.

It looks like a DIY version of the silicone polymers they use on large ships. There’s no biocide needed in that for it to function, and I’d like to try it out on a prop and lower unit, because it’s slippery too.

Its compatibility with what you have on your hull now is a tossup, I’d say. I’d really like to know how this stuff works for you, though. Maybe leave a small defined patch of your hull untreated for a comparison(?) Please keep us posted!

- Brian.

ps. If Canadian Tire sell lots of this stuff, it'll be just a matter of time before they sell a Motomaster brand version for the value-minded customer; diluted 50%, and for 75% of the price.

Hi, is the need for a barrier coat only an issue with the or does the 26C or S need one as well ? Mine is due a repaint in forseable future, as a prev paint job from a few years before I bought "Rockhopper" is starting to flake away. I had kept her in the water most of last season ... no pitting seen so far.

Hi FS!

Blistering is a risk for all gel coated polyester fibreglass boats that spend any length of time in the water. It's less likely to happen on trailered boats that spend less time in the water before being hauled out to dry.

Gel coat (the coloured outer layer of the boat) is very porous and permeable to water, so the thickness of the gelcoat is quite irrelevant to keeping water out. The water moves freely through the gelcoat layer until it reaches the resin below it, where it will dissolve the matrix itself, unreacted components, as well as other solute by-products present from the process, such as glycol. The presence of oxygen (which inhibits the setting process), incomplete mixing, and a large number of other factors and conditions at the time of production combine to insure that soluble components are present.

High school chemistry teaches us that water will move in a direction across a concentration gradient so as so decrease that gradient. That is precisely what happens across the gel coat "membrane". Water migrates from outside the hull, through the gelcoat, and into the polyester matrix to dilute the concentrated solutes formed there.

As you can imagine, this leads to pockets of swelling in these areas. Which leads to small blisters where the gelcoat is thin, or cracks where the gelcoat is thick. The intent of barrier coats is to provide a water-impermeable barricade that prevents water from migrating across it, (which is why it is so important to apply them to a hull that has had adequate time to dry out) and to provide a solid substrate for anti-foul coatings.

It does appear that blistering might be more likely to happen in brand new boats (within a few months old), possibly because there are more unreacted components present. Blistering is also more common in fresh than salt water, which you would expect to see, because the concentration gradient, and thus the osmotic pressure, is greater in fresh water.

It's hard to say without knowing exactly what is on your hull, but it might be a barrier coat on first, with other coatings outside that. So your barrier might be intact, with outer coating flaking off(?) The normal practice is to leave a barrier coat on the hull for its life, and just to renew the anti foul coatings over time, but this is not always practical.

There is also a certain equilibrium that is reached based on seasonal cycling. If you have not had blistering, I would approximately adhere to that schedule if possible. If the hull spends, say, 4 months out of the water, it is drying out from the 8 months it spent in the water, and no problem surfaces. The boat comes out of the water ahead of the appearance of blistering, and then dries out during storage to start all over again next season.

I'm a big fan of preventive maintenance, mostly because it's logical, and I want the biggest bang for the buck. The downside of not barrier-coating your boat is a big expensive-to-repair mess. The upside of not barrier-coating is you might get away without it for a while and save the hassle and money. But of course it's up to each individual to decide based on their own circumstances, and also depends on the value you place on your boat.

Have fun!

- Brian.

Thank you all for the advice. Looks like I'll have a bit of work to do!
How long will the barrier coat last for? Will this be a yearly ritual? ... Sure hope not.

Ray

If the barrier coat has been properly applied it should last a long time. The anti-foul coats applied on top of the barrier coat need to be renewed at intervals that depend on the individual product being used, and the usage patterns and conditions. The name of the game is the ongoing renewal of the surface layers without disturbing the barrier layer.

Ablative anti-foul coatings need renewal at regular intervals because, by definition, they are designed to continuously wear away and expose a fresh surface beneath.

Biocides incorporated into the surface of any anti-foul coating diffuse out with decreasing effectiveness over time (bad for the environment; they often contain biotoxic elemental copper and other compounds). Contrary to what you might think, some products actually continue to (at a greater rate than when wet) lose effectiveness during the seasonal period when they are out of the water drying.

I’m expecting to go 2 (maybe 3) years with touch-ups between anti-foul re-applications. Applying a blue layer on top of black helps to make it easier to judge when to do this- the black will show through the blue where it needs renewal or touching-up. The barrier is grey, so I’ll know by the colour which layer I’m dealing with.

- Brian.

seahouse wrote:......Applying a blue layer on top of black helps to make it easier to judge when to do this- the black will show through the blue where it needs renewal or touching-up. The barrier is grey, so I’ll know by the colour which layer I’m dealing with. - Brian.

That is what we did. I have 2 coats of black over the barrier coat and one coat of blue over the black and so far no black showing. On the S 2 gallons mixed of the Tuff Stuff gave the recommended 2 coats of barrier paint and 1 gallon of black anti-fouling gave 2 coats. Still have 1/2 gallon of the blue,

Sum

Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links