What causes blisters on the bottom of the hull? What can you do to repair them? Dose it affect the value of the boat and how much?
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Hello Ron, A good place to start learning more about blisters is to check these two web site. http://www.yachtsurvey.com/BuyingBlisterBoat.htm and www.osmosisinfo.com.(this one now charge 17,95$ for full access), but both of these sites will let you know what is happening and what they suggest. If it is a problem your boat has, the final decision will be yours but at least you will be informed better informed. Good luck
Depends on who you want to believe.
Does it affect the value of the boat? Absolutely! When a bottom job for blisters can cost $3-4k or more for a 27 ft. it will affect the value. There are several schools of thought on the causes. Depending on how severe the blisters are there are different methods on how to repair them. Do some searches on the internet and see what you come up with. I would not purchase a boat with blisters unless the owner was picking up the tab. There are too many boats out there that either do not have them or they have been repaired.
Does it affect the value of the boat? Absolutely! When a bottom job for blisters can cost $3-4k or more for a 27 ft. it will affect the value. There are several schools of thought on the causes. Depending on how severe the blisters are there are different methods on how to repair them. Do some searches on the internet and see what you come up with. I would not purchase a boat with blisters unless the owner was picking up the tab. There are too many boats out there that either do not have them or they have been repaired.
What causes blisters...
Blisters are cause by improperly applied bottom paint, insufficient barrier coats, and failure to care for the bottom (too long in between coats for example). Water penetrates the gelcoat through tiny cracks and becomes trapped between it and the next layer of fiberglass. The gelcoat swells and you have bubbles or blisters. The products: Here, you have several options. West System is the most expensive, but the best and longest lasting solution. The process of applying West System to repair blisters is a long and difficult task, and I would not suggest trying it on your own unless you have worked with West System before. Interlux also has a line of products to repair blisters. It is moderately priced and easy to apply. I used the Interlux system to repair my C-22 earlier this year and I would recommend you try this method. Seafit makes several kits, but I do not recommend using any of them except to fix something above the waterline. The process: Sand or grind out all of the blisters. Remove all of the bottom paint currently on the hull by whatever means are acceptable in your area (paint removers, sanding, grinding). Let the boat dry out. This could take days or weeks depending on the severity of the water penetration. Next, I stongly suggest using a mix of West System Epoxy and West System 410 filler to fill the blisters (and any other imperfections on the bottom) that have been sanded/grinded. Let it dry completely. Sand until uniform. Now back to the Interlux products. Apply a coat of Interlux Interprotect 2000/2001. Let dry completely. Apply Interlux Interprotect Watertite (this stuff is like peanut butter and goes on kind of like a paste wax). After it has dried, sand it smooth (this is time consuming). Add three more coats of Interprotect 2000/2001 letting it fully dry in between coats. Add the bottom paint of your choice and you are ready to get back on the water. I would estimate the cost of this project on a 27 footer to be around $1000 to $1200 including bottom paint and necessary tools. Using West System for the whole job would cost upwards of $2000. These are do-it-yourself prices. Double it for the pros to do the job. Does it affect the price? I would not buy a boat with a bad bottom without expecting some kind of deal. At the same time, I would be inclined to pay a little more (not the full price of the bottom job) for a boat with a freshly repaired bottom (but I am going to poke and scratch around with a screwdriver to make sure it was done right).
Blisters are cause by improperly applied bottom paint, insufficient barrier coats, and failure to care for the bottom (too long in between coats for example). Water penetrates the gelcoat through tiny cracks and becomes trapped between it and the next layer of fiberglass. The gelcoat swells and you have bubbles or blisters. The products: Here, you have several options. West System is the most expensive, but the best and longest lasting solution. The process of applying West System to repair blisters is a long and difficult task, and I would not suggest trying it on your own unless you have worked with West System before. Interlux also has a line of products to repair blisters. It is moderately priced and easy to apply. I used the Interlux system to repair my C-22 earlier this year and I would recommend you try this method. Seafit makes several kits, but I do not recommend using any of them except to fix something above the waterline. The process: Sand or grind out all of the blisters. Remove all of the bottom paint currently on the hull by whatever means are acceptable in your area (paint removers, sanding, grinding). Let the boat dry out. This could take days or weeks depending on the severity of the water penetration. Next, I stongly suggest using a mix of West System Epoxy and West System 410 filler to fill the blisters (and any other imperfections on the bottom) that have been sanded/grinded. Let it dry completely. Sand until uniform. Now back to the Interlux products. Apply a coat of Interlux Interprotect 2000/2001. Let dry completely. Apply Interlux Interprotect Watertite (this stuff is like peanut butter and goes on kind of like a paste wax). After it has dried, sand it smooth (this is time consuming). Add three more coats of Interprotect 2000/2001 letting it fully dry in between coats. Add the bottom paint of your choice and you are ready to get back on the water. I would estimate the cost of this project on a 27 footer to be around $1000 to $1200 including bottom paint and necessary tools. Using West System for the whole job would cost upwards of $2000. These are do-it-yourself prices. Double it for the pros to do the job. Does it affect the price? I would not buy a boat with a bad bottom without expecting some kind of deal. At the same time, I would be inclined to pay a little more (not the full price of the bottom job) for a boat with a freshly repaired bottom (but I am going to poke and scratch around with a screwdriver to make sure it was done right).
Matt
I have read several articles on blisters. There is absolutely no correlation between bottom paint and blisters. Bottom paint is ONLY to protect against growth. And depending on who you listen to, a barrier coat may or may not prevent blisters from occuring. Some of these "experts" claim that the blisters are built into the process of laying up the bottom. Ask around and see how many owners have had to redo a blister job. There is NO guarantee that blisters will not reoccur. There is also a correlation to where the boat is located water tempatuure and fresh or salt. SO, there really is no definitive answer to this problem. And as I said, it depends on who you want to believe (not me).
I have read several articles on blisters. There is absolutely no correlation between bottom paint and blisters. Bottom paint is ONLY to protect against growth. And depending on who you listen to, a barrier coat may or may not prevent blisters from occuring. Some of these "experts" claim that the blisters are built into the process of laying up the bottom. Ask around and see how many owners have had to redo a blister job. There is NO guarantee that blisters will not reoccur. There is also a correlation to where the boat is located water tempatuure and fresh or salt. SO, there really is no definitive answer to this problem. And as I said, it depends on who you want to believe (not me).
Ron; It really depends on how severe the blisters are. A bunch of small one's in a specific area are not something to worry about, and is an easy repair. Medium to large one's all over the bottom, well, that is a major repair job. Steve is right, bottom paint does not stop blisters from forming. Mike
Matt, bottom paint has no effect on blisters,
positive or negative. Bottom paint won't prevent blisters, nor will the absence of bottom paint cause 'em...because bottom paint doesn't protect the gelcoat from moisture. How well a bottom is cared for doesn't cause or prevent blisters either...some boats develop serious blisters in a single season, others sit unattended in the water for years without ever a single blister. Everyone has a theory about what causes 'em, but in fact, there's no way to predict which boats will get blisters and which won't. How serious they are depends on how large and how deep. So does how to fix 'em and whether to apply a barrier coat to prevent 'em again (several thousand $$). Tiny shallow blisters can easily be fixed--open 'em, let 'em dry, fair the bottom again. Large deep ones can require major expensive work. The age and value of the boat, as well as the seriousness of the blisters, is a factor in whether to spend the money for a barrier coat. For instance, my own boat was 20 years old...hadn't been hauled in 11 years (fresh water, so not a problem there) when I bought her...her bottom was peppered with little tiny shallow blisters. The consensus opinion of both the surveyor--one of the best in the country--and the shop I hired to do the bottom work was, no barrier coat...because a 20 year old boat--or even a 10 year old boat--had prob'ly already gotten all the blisters she was ever gonna get. None were serious, so the likelilhood of serious blisters in the future was virtually nil...and the cost of repairing any more small ones--IF they ever occurred--for the next 20 years couldn't begin to equal the price of a barrier coat. If, otoh, the boat were only a few years old, or the blisters had been more serious, that would not have been the way to go. So, Ron...what you need is some expert advice from a knowledgable surveyor and yard that's also experienced and knowledgable about blisters after they've looked at our boat (or the one you're considering buying)...'cuz "blisters" is a VERY broad subject...and despite the fact that everyone has opinions, there aren't any "one size fits all" answers as to how serious they are--some are serious, some aren't, or the best way to deal with 'em on any individual boat.
positive or negative. Bottom paint won't prevent blisters, nor will the absence of bottom paint cause 'em...because bottom paint doesn't protect the gelcoat from moisture. How well a bottom is cared for doesn't cause or prevent blisters either...some boats develop serious blisters in a single season, others sit unattended in the water for years without ever a single blister. Everyone has a theory about what causes 'em, but in fact, there's no way to predict which boats will get blisters and which won't. How serious they are depends on how large and how deep. So does how to fix 'em and whether to apply a barrier coat to prevent 'em again (several thousand $$). Tiny shallow blisters can easily be fixed--open 'em, let 'em dry, fair the bottom again. Large deep ones can require major expensive work. The age and value of the boat, as well as the seriousness of the blisters, is a factor in whether to spend the money for a barrier coat. For instance, my own boat was 20 years old...hadn't been hauled in 11 years (fresh water, so not a problem there) when I bought her...her bottom was peppered with little tiny shallow blisters. The consensus opinion of both the surveyor--one of the best in the country--and the shop I hired to do the bottom work was, no barrier coat...because a 20 year old boat--or even a 10 year old boat--had prob'ly already gotten all the blisters she was ever gonna get. None were serious, so the likelilhood of serious blisters in the future was virtually nil...and the cost of repairing any more small ones--IF they ever occurred--for the next 20 years couldn't begin to equal the price of a barrier coat. If, otoh, the boat were only a few years old, or the blisters had been more serious, that would not have been the way to go. So, Ron...what you need is some expert advice from a knowledgable surveyor and yard that's also experienced and knowledgable about blisters after they've looked at our boat (or the one you're considering buying)...'cuz "blisters" is a VERY broad subject...and despite the fact that everyone has opinions, there aren't any "one size fits all" answers as to how serious they are--some are serious, some aren't, or the best way to deal with 'em on any individual boat.
This is true but........
If and when you go to sell the boat (that has blisters) you are going to be hard pressed to sell it without fixing them. You are only going to find one in 20 buyers that will purchase the boat without an adjustment for the fix or having the problem fixed before they take possession.
If and when you go to sell the boat (that has blisters) you are going to be hard pressed to sell it without fixing them. You are only going to find one in 20 buyers that will purchase the boat without an adjustment for the fix or having the problem fixed before they take possession.
Blister price
We bought a boat with serious blisters for a huge discount. Original asking price on the '77h27 was $9500. We eventually got him down to $4300. (Of course, the electical system and sails were shot too... *sigh*) We're going to roll up our sleaves and "fix" it this winter...
We bought a boat with serious blisters for a huge discount. Original asking price on the '77h27 was $9500. We eventually got him down to $4300. (Of course, the electical system and sails were shot too... *sigh*) We're going to roll up our sleaves and "fix" it this winter...
Well...duh, Steve...
I never suggested not fixing 'em. But there is no "one size fits all" answer to the right way to fix 'em. That depends upon how serious they are, the age of the boat, how likely they are to re-occur, and several other factors. There's no way anyone here can advise Ron what to do--whether it's necessary to spend the money for a barrier coat, or just open 'em, dry 'em out, fill 'em, and fair the bottom--because none of us have seen 'em. And even if we could see 'em, few people here-- if any--have the knowledge and expertise to know what's necessary for this particular situation.
I never suggested not fixing 'em. But there is no "one size fits all" answer to the right way to fix 'em. That depends upon how serious they are, the age of the boat, how likely they are to re-occur, and several other factors. There's no way anyone here can advise Ron what to do--whether it's necessary to spend the money for a barrier coat, or just open 'em, dry 'em out, fill 'em, and fair the bottom--because none of us have seen 'em. And even if we could see 'em, few people here-- if any--have the knowledge and expertise to know what's necessary for this particular situation.
Peggy...
Are you saying that you had the tiny blisters repaired on your boat (my surveyor called em "boat pox")? If so, did they peel the gel coat, etc.? But no barrier coat on top of the new gel coat. Just curious because your response is excellent and I'm wondering how you handled the repairs on your boat.
Are you saying that you had the tiny blisters repaired on your boat (my surveyor called em "boat pox")? If so, did they peel the gel coat, etc.? But no barrier coat on top of the new gel coat. Just curious because your response is excellent and I'm wondering how you handled the repairs on your boat.
I firmly believe that blisters come from
or are at least contributable to improper care of a boats bottom. No matter if there are imperfections in the gelcoat and glassed layers, if you have a good bottom job, i.e. barrier coats, fillers, and bottom paints, you can avoid blisters by not allowing the water to penetrate the gelcoat (I recognize the fact that blisters can come from the bilge as well, but here too, if you take care of it, it ain't going to happen). But, like many of you say, this subject is up for debate. All I know is that the only boat that I have ever owned that had blisters had a crappy bottom job with no barrier coat.
or are at least contributable to improper care of a boats bottom. No matter if there are imperfections in the gelcoat and glassed layers, if you have a good bottom job, i.e. barrier coats, fillers, and bottom paints, you can avoid blisters by not allowing the water to penetrate the gelcoat (I recognize the fact that blisters can come from the bilge as well, but here too, if you take care of it, it ain't going to happen). But, like many of you say, this subject is up for debate. All I know is that the only boat that I have ever owned that had blisters had a crappy bottom job with no barrier coat.
Here's what we did, Don...
Solitaire's bottom had acne--nothing bigger than dime, nothing deeper than the gelcoat. We drilled every of 'em out, let the boat sit for a month to make sure it was dry...the surveyor sounded the hull and put a moisture meter on it...filled the "scars" with epoxy and new gelcoat...faired...and bottom paint. No gelcoat peel...it wasn't necessary. No barrier coat either...she hadn't been out of the water in 9 years...she'd gotten all the blisters she was ever likely to get, so a barrier coat would have been a waste of money. Total cost: $2500, plus haulout and yard storage for a month. A barrier coat would have more than doubled the cost--money better spent only if necessary to repair any new blisters. I'm NOT saying that this is the way to handle every blister situation. It was the right way to repair THIS boat. Btw...I made good use of the time she sat in the yard...had all the thru-hulls replaced, rebedded etc...all the gelcoat dings repaired, and the whole boat wet sanded, buffed, re-striped, and teflon coated. By the time she went back in the water she looked like a brand new boat--which, including everything I'd replaced inside, she was!
Solitaire's bottom had acne--nothing bigger than dime, nothing deeper than the gelcoat. We drilled every of 'em out, let the boat sit for a month to make sure it was dry...the surveyor sounded the hull and put a moisture meter on it...filled the "scars" with epoxy and new gelcoat...faired...and bottom paint. No gelcoat peel...it wasn't necessary. No barrier coat either...she hadn't been out of the water in 9 years...she'd gotten all the blisters she was ever likely to get, so a barrier coat would have been a waste of money. Total cost: $2500, plus haulout and yard storage for a month. A barrier coat would have more than doubled the cost--money better spent only if necessary to repair any new blisters. I'm NOT saying that this is the way to handle every blister situation. It was the right way to repair THIS boat. Btw...I made good use of the time she sat in the yard...had all the thru-hulls replaced, rebedded etc...all the gelcoat dings repaired, and the whole boat wet sanded, buffed, re-striped, and teflon coated. By the time she went back in the water she looked like a brand new boat--which, including everything I'd replaced inside, she was!
If it's raining outside and you want to keep your
feet dry, there are many options but the best way to do it is with a good pair of rubber boots. If you want to fix the blisters on your boat and reduce the likelihood of them reoccuring, there are many options but the best way is to follow the advice that I have given and use a barrier coat. It is a tried and true method. We all agree that blisters are pockets of water in between the gelcoat and layers of fiberglass (don't we?). Simple logic dictates that if you remove the water contact from the gelcoat, you can prevent blisters from occuring. This is best done with a barrier coat. While they can occur from inside the bilge, a simple solution is bilge paint and a bilge pump. Barrier coats are an important component to the bottom of your boat. They 1) keep water out, 2) serve as a primer for your bottom paint, and 3)they keep water out. Not putting a barrier coat on a boat that sits in the water for extended periods of time is only asking for trouble. It's like not changing the oil in your car...
feet dry, there are many options but the best way to do it is with a good pair of rubber boots. If you want to fix the blisters on your boat and reduce the likelihood of them reoccuring, there are many options but the best way is to follow the advice that I have given and use a barrier coat. It is a tried and true method. We all agree that blisters are pockets of water in between the gelcoat and layers of fiberglass (don't we?). Simple logic dictates that if you remove the water contact from the gelcoat, you can prevent blisters from occuring. This is best done with a barrier coat. While they can occur from inside the bilge, a simple solution is bilge paint and a bilge pump. Barrier coats are an important component to the bottom of your boat. They 1) keep water out, 2) serve as a primer for your bottom paint, and 3)they keep water out. Not putting a barrier coat on a boat that sits in the water for extended periods of time is only asking for trouble. It's like not changing the oil in your car...
Hey Matt !!
So Matt is it your contention that, if the work is done well and the barrier coat is done well enough we will never get blisters. If that is the case do we still need bottom paint in fresh water lakes? I even wonder whether we should be using bottom paint on lakes retaining water for domestic consumption.
So Matt is it your contention that, if the work is done well and the barrier coat is done well enough we will never get blisters. If that is the case do we still need bottom paint in fresh water lakes? I even wonder whether we should be using bottom paint on lakes retaining water for domestic consumption.
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