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Old 15-11-2017, 12:49   #1
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Bottom job: Unknown hard bottom paint currently, do I need to strip?

Boat (1988 Gulf 32, 23.33' LWL long keel, in Pacific Northwest) has hard bottom paint on it currently, our diver is telling us it's time for a bottom job so we are researching options.

This is a new to us boat, we have no idea what's on there now, but it certainly doesn't appear to be ablative. When we have been hauled (once for survey 2 years ago, once for work done 1 1/2 years ago) the bottom looked overall pretty good (I can post pictures from 1 1/2 years ago if that helps), no blisters, survey said bottom paint was in good condition.

The yard that hauled in it March of 2016 sanded and repainted a small area around the shaft that had some haloing and applied some more paint over the sanded areas (not sure what) and that appears to have held up fine.

I contacted the yard about a bottom job and their original proposal is that we should strip the hull, apply 4 coat epoxy barrier coat and 2 coats bottom paint.

This seems excessive to me but I don't know much about this... is this just the conservative, best way to go if you don't know what the current bottom paint is? What kind of risk am I running if I just ask them to do a light sanding and 2 coats of bottom paint on top of the current (seemingly OK, but what do I know?) bottom paint? Is an epoxy barrier coat going to be a necessity sooner or later on a boat that has no blisters and (AFAIK) no history of blisters?

Thanks in advance to any advice on this one, appreciate it.

-- Bass
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Old 15-11-2017, 13:00   #2
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Most antifoul paint companies also sell a tie-coat primer that will go over most any clean paint. Apply a tie-coat primer and paint with an ablative. If in 1 or 2 years you don't like the performance of the bond you can strip then. It will most likely be just fine.
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Old 15-11-2017, 13:05   #3
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Quote:
Originally Posted by basssears View Post
Boat (1988 Gulf 32, 23.33' LWL long keel, in Pacific Northwest) has hard bottom paint on it currently, our diver is telling us it's time for a bottom job so we are researching options.

This is a new to us boat, we have no idea what's on there now, but it certainly doesn't appear to be ablative. When we have been hauled (once for survey 2 years ago, once for work done 1 1/2 years ago) the bottom looked overall pretty good (I can post pictures from 1 1/2 years ago if that helps), no blisters, survey said bottom paint was in good condition.

The yard that hauled in it March of 2016 sanded and repainted a small area around the shaft that had some haloing and applied some more paint over the sanded areas (not sure what) and that appears to have held up fine.

I contacted the yard about a bottom job and their original proposal is that we should strip the hull, apply 4 coat epoxy barrier coat and 2 coats bottom paint.

This seems excessive to me but I don't know much about this... is this just the conservative, best way to go if you don't know what the current bottom paint is? What kind of risk am I running if I just ask them to do a light sanding and 2 coats of bottom paint on top of the current (seemingly OK, but what do I know?) bottom paint? Is an epoxy barrier coat going to be a necessity sooner or later on a boat that has no blisters and (AFAIK) no history of blisters?

Thanks in advance to any advice on this one, appreciate it.

-- Bass
We have a new to us two years ago 1977 Bristol 29.9. A similar sized boat.
We did a bottom job on ours, scraped down to the gel coat, then sanded the remainder of the bottom paint off, then did four coats of barrier coat, then two coats of bottom paint. Now granted our boat is older than yours, but consider, that it is the part of your boat that is under water all the time. and it will serve you well to have done it.
If you are wanting to, you can go on adventuresontheclub.com and look at some pictures of us doing the bottom job, it may or may not be helpful with your decision of what to do.

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Old 15-11-2017, 13:07   #4
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Typically you can expect to get 2-3 years out of a good bottom paint in the PNW. Depending on how much the paint is built up and how smooth the surface is right now will determine if it's time to completely remove the paint down to gelcoat. If your tight on time and money and the bottom is fairly smooth you can give it a good sanding and apply more bottom paint. Be sure you know the compatibility of your current and new antifouling before you make your purchase. If the bottom is quite rough then it makes sense to scape and sand to start over again but it's labor unless you do it yourself.
Blisters...no guarantee on getting or not getting them. Typically the worst water to be in is warm fresh water then cool fresh water then warm salt water and finally cool salt water so your in an area that is the least likely to get blisters.
If you decide to scape/sand your built up bottom paint off your going to need an undercoat/primer anyways so one of the better ones is epoxy, something like Interprotect 2000E and all you really need is one heavy coat to act as a primer. Make sure you get your first coat of antifouling paint on while you can still see a finger print as you will get an excellent bond, if you wait too long you'll need to sand it. Personally if your boat shows no sign of blisters I'd probably not go through the process without a long drying period on the hard. Cheers, R
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Old 15-11-2017, 13:14   #5
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Thanks for the responses, one additional points I'll add is that I will almost certainly be paying a yard to do this. We live 700+ miles from our boat, and between travel / lodging / time off work / not having any tools locally etc we'd rather spend that time sailing and pay someone to do the work for us, even though I realize the vast amount of the cost of a bottom job is labor.

-- Bass

(Oh, and I guess I should have modified the subject to read "do I need to strip THE HULL" )
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Old 15-11-2017, 13:38   #6
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

You need to decide if it is worth the risk for expensive job you just paid the yard to just fall off. If the current isn’t coming off you probably can get by with a sand, prime, paint instead of stripping. But otherwise it’s time for the old to come off.
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Old 15-11-2017, 14:01   #7
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Bottom job: Unknown hard bottom paint currently, do I need to strip?

If there are no apparent problems other than rough paint I would just sand and repaint. The question is how much to sand and that’s a direct function of how built up and/or chipped it is. Ideally you’d have the yard haul the boat, power wash, and send you pictures before they do anything else so you can evaluate and make some decisions.

If it is hard paint you want to take it down a reasonable amount; leave a base (ie don’t expose the barrier or gelcoat), but get off as much as possible. Hard paint does not wear away and if you just do a light sanding you’re kicking the can down the road, setting up conditions for chipping/detachment, and generally making the job more difficult in future.

I would have the yard give you a written estimate with a “not to exceed” clause of 15% to protect yourself from “Oh we ran into issues” or “It needed more than we thought”. Owners at a distance are viewed as open checkbooks by lots of yards.
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Old 15-11-2017, 14:59   #8
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Lets see if I have this right: 29 year old boat, no blisters, current unknown hard paint in decent shape except for antifouling properties... and the yard wants to strip and reapply barrier coats? Sounds like make-work to me!

In your position, I'd pressure wash, light sand, apply a compatible tie coat (follow the advice of the brand of antifouling you choose) and then apply the recommended number of coats of new antifouling paint. The tie coat is inexpensive and quick to apply, and will assure compatibility between old and new.

Overthinking this simple problem will only lead to excessive costs with no likely improvement in hull protection or antifouling performance.

Jim
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Old 15-11-2017, 16:06   #9
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

The assumption that people make is that you can put any hard paint on top of any other hard paint and it will stick fine. That is a bad assumption.

One option is to do as the yard has recommended and strip back to the naked hull. that is obviously the best way to do it, and the value of it depends on how many layers of paint are already on there. If there are a lot of layers, they need to come off sometime, so why not now? If it is relatively thin, it's not such a value...

What to do instead of stripping? Use a suitable primer. I have successfully used Primeocon to very successfully tie a hard paint on top of an ablative. Each paint brand has it's own, but that is one I can recommend as doing a good job even when making a switch that most people consider impossible. It takes a few coats, but they go on very fast and easy, and the paint itself is not very expensive as these things go. It is an excellent surface prep.
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Old 15-11-2017, 16:51   #10
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Not knowing what you have on there now, it is a craps-shoot to just paint over it. Some new bottom paints are very tolerant to chemical incompatibilities, while others are much less so. It depends a lot on what brand/type of paint you want to put over it, and how tolerant or averse you are to risk.

For example this is the compatibility chart for Pettit paints:

http://www.pettitpaint.com/fileshare...patibility.pdf

I have seen some pretty adverse effects of extreme bottom paint incompatibilities, to the point that the whole bottom anti-foul area shriveled up and wrinkled like an sun-dried raisin, right through and including the primer coats like someone had applied gallons of aircraft paint stripper to the paint, exposing the bare fiberglass/gelcoat beneath the cracks and craters. Good solid gelcoat probably would not have any issues here, but if the hull ever had any repairs that were just primered-over instead of new gelcoat you might be exposing your hull to possible moisture intrusion in worst-case scenarios.
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Old 15-11-2017, 17:07   #11
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Quote:
Originally Posted by basssears View Post
Boat (1988 Gulf 32, 23.33' LWL long keel, in Pacific Northwest) has hard bottom paint on it currently, our diver is telling us it's time for a bottom job so we are researching options.

This is a new to us boat, we have no idea what's on there now, but it certainly doesn't appear to be ablative. When we have been hauled (once for survey 2 years ago, once for work done 1 1/2 years ago) the bottom looked overall pretty good (I can post pictures from 1 1/2 years ago if that helps), no blisters, survey said bottom paint was in good condition.

The yard that hauled in it March of 2016 sanded and repainted a small area around the shaft that had some haloing and applied some more paint over the sanded areas (not sure what) and that appears to have held up fine.

I contacted the yard about a bottom job and their original proposal is that we should strip the hull, apply 4 coat epoxy barrier coat and 2 coats bottom paint.

This seems excessive to me but I don't know much about this... is this just the conservative, best way to go if you don't know what the current bottom paint is? What kind of risk am I running if I just ask them to do a light sanding and 2 coats of bottom paint on top of the current (seemingly OK, but what do I know?) bottom paint? Is an epoxy barrier coat going to be a necessity sooner or later on a boat that has no blisters and (AFAIK) no history of blisters?

Thanks in advance to any advice on this one, appreciate it.

-- Bass

So, if I read this right, you asked the same yard which painted it last to paint it again? Because if that's the case, they certainly ought to know what's on there. Also, it sounds like the boat hasn't even been hauled out and pressure washed yet, they just made the assumption that it's time sight unseen? Based on what, diver's pics? Previous knowledge from the last time they coated it? Or?


Are my above assumptions based on your text correct?



What yard is it? Spill the beans...
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Old 15-11-2017, 19:41   #12
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

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So, if I read this right, you asked the same yard which painted it last to paint it again? Because if that's the case, they certainly ought to know what's on there.
They did not paint the whole bottom, they just touched up the area they sanded in front of where the shaft exits the keel. So they haven't done a "bottom job" for me per se, but now that you put it that way, they slapped some paint on there, they should know what they put on there, whatever it was didn't fall off!!

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Also, it sounds like the boat hasn't even been hauled out and pressure washed yet, they just made the assumption that it's time sight unseen? Based on what, diver's pics? Previous knowledge from the last time they coated it? Or?
You are correct that they have not seen the boat since April of 2016 (last time we were out of the water). We are assuming it's time for a bottom job because the diver we have used twice before said after the last time that he thinks we need to have the bottom done.[/QUOTE]

Quote:
Originally Posted by minaret View Post
Are my above assumptions based on your text correct?

What yard is it? Spill the beans...
Yes, you are basically correct, this is all sight unseen, done by email so far, just my preliminary investigation with a yard that has treated me well in the past. Maybe they're looking at a slow winter and are trying to build work (they also gave me what I thought was an rather high quote for a swim step), dunno.

Yard is Seaview North in Bellingham, WA... like I said I've used them once before after we bought the boat and was VERY happy with the work they did (the things they "found" needed to be found, they weren't make work, the work they did has stood up very well, and they did everything on time and on budget).
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Old 15-11-2017, 19:44   #13
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

Thanks to everyone who's replied so far, your input is much appreciated.

I don't know a lot of sailors to ask these questions to (central Idaho isn't exactly a hot bed of much more than Hobie 14's!) so it's very helpful to hear different opinions and process them for myself.

Here's an add on question... what's worst case scenario if we don't do this yet. Say the diver is right and it probably is time to have the bottom done, and we don't do it until next fall, or spring 2019. Obviously I'm going to have more growth that's harder to remove, but presuming the diver is still willing to dive the boat and remove it (while checking/changing zincs etc), am I risking other problems by waiting or just risking a slow, dirty hull?

-- Bass
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Old 16-11-2017, 04:57   #14
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

The diver will have to work harder at it, but get to do it more often. The funny thing is when you add up the total cost of the bottom job you find the diver might be less expensive.
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Old 16-11-2017, 05:34   #15
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Re: Bottom job: Unknown hard bottom paint currently, do I need to strip?

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The diver will have to work harder at it, but get to do it more often. The funny thing is when you add up the total cost of the bottom job you find the diver might be less expensive.
Could very well be. Here in Chicago, where we are for another half season, a lot of folks just let it get really bad over the summer and since the season is so short they get away without cleaning at all. The boat gets cleaned at haul-out with a pressure washer. A lot of boats at the yard have really horrible bottom paint if you walk around looking at them. We don't have the barnacle problem here except for a few zebra muscles in the fresh water and the grass usually doesn't grow too long in the short few months before we need to haul out again. It looks really bad and I'm sure is slows the boat down quite a bit. But by the end of September you see some really filthy boats out there moored in the harbor. Many of neighbors never have their boats cleaned in the water or do it themselves.

I went nuts on our bottom job because I don't want to deal with it nearly as much since we plan on going places where it will be a lot growth due to warmth and sun. Once we get to the Caribbean the bottom paint will be working a lot harder, and we plan on anchoring out and not staying at marinas where we will have an opportunity to hire people to clean our bottom for us. We'll be doing it ourselves, so I wanted to make the job as painless as possible. Here in Chicago we got zero growth with the Petitt Ultima SR-60. It looked like we had launched earlier that week by the time we went back to the boatyard. It was that clean. This paint was WAY overkill here.

If money isn't an issue, and for anyone staying at a marina, or a string of marinas, long-term with a l50' + large boat it really must not be, then it's just the inconvenience of finding someone to take your cash on a regular basis to do this job for you.

It's just a boat...
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