Barrier coat now or later?

[Cthoops]

Our new-to-us Bristol 29.9 has very likely spent her whole life in the northeast. She currently does not have a barrier coat, and she doesn't have any blisters.

The plan is to cut the lines and head for warmer climates in May 2021, so we'll definitely want to put on a barrier coat before we leave.

The bottom paint job by the prior owner's yard left a lot to be desired with patches that are flaking off down to the gelcoat, so it seems like a logical time for us to remove the existing bottom paint and put on a proper barrier coat before repainting.

How long can we expect a barrier coat to last? 10 years? Longer? I don't want to undertake this big DIY job too soon only to be hauled out in who-knows-where having to sand everything down to the fiberglass again.

[a64pilot]

I thought they lasted until removed?

[minaret]

Originally Posted by Cthoops

Our new-to-us Bristol 29.9 has very likely spent her whole life in the northeast. She currently does not have a barrier coat, and she doesn't have any blisters.

The plan is to cut the lines and head for warmer climates in May 2021, so we'll definitely want to put on a barrier coat before we leave.

The bottom paint job by the prior owner's yard left a lot to be desired with patches that are flaking off down to the gelcoat, so it seems like a logical time for us to remove the existing bottom paint and put on a proper barrier coat before repainting.

How long can we expect a barrier coat to last? 10 years? Longer? I don't want to undertake this big DIY job too soon only to be hauled out in who-knows-where having to sand everything down to the fiberglass again.

Be sure the substrate is sufficiently dry before application, and it should last your lifetime.

[model 10]

Why do you need a barrier coat? I would take a good gel coat surface any day. Only reason to put on a barrier coat is if your gel coat fails.

[minaret]

Originally Posted by Guy

Why do you need a barrier coat? I would take a good gel coat surface any day. Only reason to put on a barrier coat is if your gel coat fails.

To prevent gelcoat blistering, perhaps?

[model 10]

Originally Posted by minaret

To prevent gelcoat blistering, perhaps?

So you are saying all gel coats blister?

[a64pilot]

Originally Posted by minaret

Be sure the substrate is sufficiently dry before application, and it should last your lifetime.

My boat was barrier coated by the OP, and I'm sure he didn't let the hull dry.
It had little "Pox" gelcoat blisters when I surveyed the boat, last year at haul out there were many fewer one, seems like they are diminishing?
But I theorize the yard sealed in moisture when they did the barrier coat, these little .25" blisters were in the gelcoat only

[GordMay]

Originally Posted by minaret

Be sure the substrate is sufficiently dry before application, and it should last your lifetime.

Indeed; so do it now (after drying).

[SVTatia]

Originally Posted by Cthoops

Our new-to-us Bristol 29.9 has very likely spent her whole life in the northeast. She currently does not have a barrier coat, and she doesn't have any blisters...

Originally Posted by Guy

Why do you need a barrier coat? I would take a good gel coat surface any day. Only reason to put on a barrier coat is if your gel coat fails.

Do it whenever you can let it sit for while to dry out.
My boat is 48 years old and since I had it out on the hard for a refit, I removed the bottom paint and applied barrier coat.
It did not have any blisters, but why not prevent? I know that if it did not get blisters in 48 years it will not in the next 10 or so, but why not?

Cthoops, food for thought:

Removing the bottom paint was the worst job I ever did, and I will not do it again, ever.
If you are willing to tackle the job, first do a search for Minaret's posts on the subject which are an absolute must, then give some thought to which bottom paint you are going to choose.
In my case, I plan to go to tropical waters in a few years, and I want Micron CSC, so what I did was to look a the Micron compatibility chart and pick a paint that was
1) Cheaper
2) recommended for cold fresh water
3) Compatible with Micron CSC.

I did not want to go with an expensive paint now. I haul the boat out every year, so I picked a cheap alternative that I can apply Micron CSC on top with minimal work.
In your case, pick a less expensive paint for cold water, if you are planing to go to warm waters as you mentioned, plan accordingly.

You don't have to do this now, go sailing on your new to you boat, then plan for one summer of hard labor...

[Cthoops]

Thanks. Knowing that it will last forever should get us through the soul-sucking times during the next month or so of weekends.

Originally Posted by SVTatia

Cthoops, food for thought:

Removing the bottom paint was the worst job I ever did, and I will not do it again, ever.
If you are willing to tackle the job, first do a search for Minaret's posts on the subject which are an absolute must, then give some thought to which bottom paint you are going to choose.
In my case, I plan to go to tropical waters in a few years, and I want Micron CSC, so what I did was to look a the Micron compatibility chart and pick a paint that was
1) Cheaper
2) recommended for cold fresh water
3) Compatible with Micron CSC.

I did not want to go with an expensive paint now. I haul the boat out every year, so I picked a cheap alternative that I can apply Micron CSC on top with minimal work.
In your case, pick a less expensive paint for cold water, if you are planing to go to warm waters as you mentioned, plan accordingly.

You don't have to do this now, go sailing on your new to you boat, then plan for one summer of hard labor...

Fantastic advice, thanks! Picking something compatible is an excellent idea. We'll do that.

[ramblinrod]

Originally Posted by Cthoops

Our new-to-us Bristol 29.9 has very likely spent her whole life in the northeast. She currently does not have a barrier coat, and she doesn't have any blisters.

The plan is to cut the lines and head for warmer climates in May 2021, so we'll definitely want to put on a barrier coat before we leave.

The bottom paint job by the prior owner's yard left a lot to be desired with patches that are flaking off down to the gelcoat, so it seems like a logical time for us to remove the existing bottom paint and put on a proper barrier coat before repainting.

How long can we expect a barrier coat to last? 10 years? Longer? I don't want to undertake this big DIY job too soon only to be hauled out in who-knows-where having to sand everything down to the fiberglass again.

I get asked this, at least 20 times per year.

We use Interlux bottom products pretty much exclusively.

My recommendation is, if the boat is more than 20 years old, and is not showing any signs of blisters, a barrier coat won't hurt, but it won't really do anything either. If water isn't getting through the gelcoat, barrier coat can't do anything, as that is what it's for.

If the boats estimate value is over $100K, a barrier coat is a worthwhile investment.

If the boat does have an osmosis problem (blisters), definitely do a barrier coat.

That being said, when we encounter anti-fouling paint that is failing, or that fails an adhesion test, we will not overcoat.

So here is our process:

1. Remove anti-fouling paint (sand or sandblast) in the fall to allow to dry all fall, winter, and spring.

2. If there are any blisters, grind them out.

3. In the spring, solvent wash the bottom.

4. If there is any exposed FRP, apply 1 coat of Epiglass epoxy, sand, and apply another coat.

5. After a weak, wash with warm soapy water to remove amine blush, and rinse.

6. Key sand.

7. Vacuum off dust and solvent wash again.

8. Apply 1 coat of Interprotect 2000 E barrier coat (as a primer).

9. If there is damage or blister divets to be repaired, fill and fair with epoxy filler and spot prime.

10. If owner wants to add barrier coat, apply 3 more coats, all within specified cure times (thumb print test).

12. After the last coat cures hard, sand smooth, vacuum, solvent wash, and apply last coat of Interprotect. (This reduces orange peel.)

13. Within specified cure time, apply anti-fouling.

For Micron CSC, we apply a base coat of contrasting colour, and then the desired colour, followed by a recoat of desired colour of high wear areas (leading underwater edges, and from top of waterline, down about 6".

While the Micron CSC job has a high initial cost, the life-cycle cost is actually least. Annual maintenance is limited to just recoating any spots that the base coat colour shows through. (On a 40 foot power boat that would take 2 gallons of Bottomkote to recover, we only use about 2 quarts of CSC.

Since the CSC does not build up over time, the need for complete anti-fouling removal (due to failure) down the road, is postponed and minimized, or completely avoided.

For sailboats (and some power boats that are used infrequently) in freshwater, we recommend VC17m instead of CSC.

Regarding blisters, check the boat immediately on haul out for blisters. Small surface blisters will disappear as the hull drys. Some small blisters will eventually become bigger blisters if left unchecked, so they are worth addressing if the cost is less than the value retention.

[model 10]

No problem pulling that off during a 30 day haul out in Panama. This is why adding a barrier coat, willy nilly is not always such a great idea. You might be better off with gel coat.

[sv Winterlude]

We chose not to barrier coat our 1985 Passport 37 before we left the US in 2001. In retrospect we think that decision was a mistake. Here's a link to our 2 cents worth.... the boat was over 15 years old and had never had a blister.... yeah.... Blisters & the Rio Dulce, Guatemala

[brantleychuck]

Your going to spend a lot of money and time solving a problem that does not exist. Survey the bottom every few years when you apply anti foul. If the blister problem comes up solve it then,


Sent from my iPad using Cruisers Sailing Forum

[valhalla360]

If it's not broke...don't fix it.

Lots of boats don't have barrier coats. If your has lasted this long, there is a very good chance it won't every have an issue.

If it does develop one, look for a cheap place down south to pull out for a month or two. It's largely a labor intensive job. If you can find a place with cheap labor and you can oversea the work, you can save money.