Don't know Jack

[All U Get]

Hi all,
I was just thinking ahead and was wondering about the bottom of my boat. When it warms up one project is to barrier coat the bottom. I've had no blisters, just thought it would be a benifit to a 30 year old boat. Anyhow, how would you epoxy around the jack stands? I'd like a continous coat, but how would you support the boat while rolling under the pads? So I don't know jack.
All U Get

 

[RichH]

Id suggest to leave well enough alone.

If the hull has not had blisters in 30 years dont CHANGE ANYTHING as you may "upset the equilibrium conditions" that are keeping your hull blister free. You wont ever 'recover' the cost and sweat equity if you plan to later sell the boat as all the surveyor/buyer is interested in is - 'no blisters'. Grinding, sanding, peeling can disturb the 'water permeability' of the laminate and can in some cases make the potential of 'blisters' worse - the historical record of failed 'bottom jobs' is legion.

go to: http://www.yachtsurvey.com/blisters.htm

 

[shemandr]

Is the bottom smooth? I could see doing this if the bottom is rough with old paint that has peeled, or in my case, new paint the yard applied poorly.
To answer your question about the jack stands: When I did a bottom I did the whole bottom except at the stands and then placed a jack stand near the one I wanted to sand/paint under and backed off the stand. It is a time consuming process. any way you do it and I didn't get my boat launched until after Memorial Day that year.
Now we're not allowed to do very much on the bottom. My back is thankful.

 

[s sauer]

I did the Interlux 2000 barrier coating many years ago and haven't had any blisters since. I did hand scrape the bottom paint down to the original epoxy primer coat and then 'continuously' applied the Interlux 2000, probably about two coats per day. I started out with eight jackstands, and was able to move a pair at a time, then move them back after the paint dried sufficiently,also using wax paper against the painted surface. My 28.5 can be reasonably supporter on five or six jack stands and its keel, but they should be chained together in pairs and on a surface that adequately supports the legs of the jack stands.

 

[All U Get]

Id suggest to leave well enough alone.

1. If the hull has not had blisters in 30 years dont CHANGE ANYTHING as you may "upset the equilibrium conditions" that are keeping your hull blister free. You wont ever 'recover' the cost and sweat equity if you plan to later sell the boat as all the surveyor/buyer is interested in is - 'no blisters'. Grinding, sanding, peeling can disturb the 'water permeability' of the laminate and can in some cases make the potential of 'blisters' worse - the historical record of failed 'bottom jobs' is legion.

go to: http://www.yachtsurvey.com/blisters.htm

Shemandr
2. To answer your question about the jack stands: When I did a bottom I did the whole bottom except at the stands and then placed a jack stand near the one I wanted to sand/paint under and backed off the stand.

S Sauer
3. I did the Interlux 2000 barrier coating many years ago and haven't had any blisters since. I did hand scrape the bottom paint down to the original epoxy primer coat and then 'continuously' applied the Interlux 2000, probably about two coats per day. I started out with eight jackstands, and was able to move a pair at a time, then move them back after the paint dried sufficiently,also using wax paper against the painted surface.

Hi Rich,
I read through your link and see there had been some awful stuff happening to one boat. As far as I know my boat has been in NE forever so before traveling further south, I was going to barrier coat it. I've seen a list of newer boats that have had that done to them in the warmer climates. What other option would there be to make the bottom less permeable?

Hi Shemandr,
Yeah the bottom was terrible, thick, chips, and I also have another issue I want to look at before it goes into the water. No worries about time and distance, it's in the backyard behind the snow pile. I didn't paint under the jack pads for two years and amazingly no growth on those squares of old paint. I'll need two more jacks to do any painting or coating.

Hi S Sauer,
What made you decide on Interlux 2000 barrier coating? I like the wax paper thought. How's Charlie Cobra get the bottom of those wood boats so nice, brace them above the waterline?
All U Get

 

[Warren Milberg]

I once again think Rich H has it right: if your boat has not developed blisters at this stage of its life, it probably will not. I've owned 5 good old boats in the past 40 yrs and none of them had blisters and/or a barrier coat. I would only considers a barrier coat on a new boat, or a relatively new boat that was showing indications of moisture penetration -- and then only after thoroughly drying out the hull (and that is a really onerous task). If you apply a barrier coat to a hull with significant moisture trapped in it, you will only make your problems worse....

If it ain't broke.....

 

[RichH]

Hi Rich,
I read through your link and see there had been some awful stuff happening to one boat. As far as I know my boat has been in NE forever so before traveling further south, I was going to barrier coat it. I've seen a list of newer boats that have had that done to them in the warmer climates. What other option would there be to make the bottom less permeable?

If you read all the www.yachtsurvey posting on 'blisters' one can approach the realization that in all probability one of the chief causes of blisters is insufficient 'wet-out' of the various layers of the laminate structure. So, it appears that for YOUR boat, perhaps the layup crew did an exceptional job when laying up the layers, and did the layup continuously until completed, etc.
The simple answer is that blisters are mostly 'hype' as one never hears of a boat sinking because it has blisters, because 99.9% of the time the blisters occur in the non-structural layers of the laminate - gelcoat and matting layer. So unless one removes the gelcoat, 'properly' removes the entire matting layer by 'peeling' or 'planing' (not by grinding, sanding or 'blasting'), then applies barrier coat etc. (a horrendous time consuming and $$$$ consuming job) then one can never be sure of the final outcome - just a good 'guess' that change (of permeation rate) will be of benefit. You have a 30 year historical record that the permeation rate is controlled, therefore 'hydrolysis' (an analog to 'rusting' of polymers) is not occurring in the internal structure of the laminate.

If you after moving the boat to warmer water or water with a higher dissolved solids concentration that gives greater probability to increased permeation ... and then blisters can develop, only then would I do any remediation. The equivalent would be having an automobile for 30 years and without any 'rust' or 'body cancer', deciding to entirely remove the paint and under-coatings (E-coat) to prevent rust or 'body cancer' - lots of work, lots of expense and most importantly you 'may have' changed the conditions that affected the original permeation rate.
Applying barrier to a hull that for 30 years was blister free, to me, would be like subjecting oneself to the horrors of "chemotherapy & radiation" in the supposition that one 'may' have identifiable cancer in the future.
Many 'blister jobs', especially DIY jobs, ultimately fail and even enhance and accelerate the 'blistering' ... leave well enough alone and only 'remediate' when there are enough significant blisters to deal with.

 

[All U Get]

Thanks again guys, it will be a few months before I can get over the snow pile to the boat to have a better look. The 5 degrees this morning put a damper on the boat list. Hopefully going to the NE Boatshow this weekend will put the smile back on my face. I'll be looking for Maine sail.
All U Get