I'm about to look at a used Catalina from 1979. I see that it will definitely need some fixing up which I'm ok with. There's one spot in the pictures that I'm a little worried about. It looks like it may be rotten. Is this something that I will need to cut out or can I just sand it away?
Hull Rot
- Thread starter Scott300
- Start date
That looks like old bottom paint to me. Fiberglass doesn't "rot". The most common way for solid fiberglass hulls to break down is water getting into the resin which shows up as blisters. Cored hulls can get water into the core which typically is found by taping the hull to look for delamination (the sound of the tap changes when you tap delaminated areas) or more commonly using a moisture meter. The dark stuff in your photo doesn't look at all like moisture in the hull.
There is a fair bit of crazing on the surface which isn't entirely uncommon in old boats. Worst case would be peeling the gel coat off and applying a new barrier coat but I wouldn't go there right away. It really doesn't look that bad. If you are concerned about it you could sand ALL of the bottom paint off and apply Interprotect 2000e then put some bottom paint back over top of that.
There is a fair bit of crazing on the surface which isn't entirely uncommon in old boats. Worst case would be peeling the gel coat off and applying a new barrier coat but I wouldn't go there right away. It really doesn't look that bad. If you are concerned about it you could sand ALL of the bottom paint off and apply Interprotect 2000e then put some bottom paint back over top of that.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,742
Welcome to the SBO forum Scott.
You already have a Catalina... Looking too build a fleet, or get a deal and flip it?
It sounds like you're doing your own survey. Makes sense on a low cost boat.
Impossible to tell from an image. You need to test the hull with a hammer (typical survey tool). Moisture meters can help if you understand their limitations.
If just flipping a boat, likely an extensive repair on a hull would not make the deal. If the boat has your eye and you are looking to commit to her, then the hull repairs and upgrading is more of a hobby for a DIY owner. Then the costs are less measured by the Benjamin's and more experience.
You already have a Catalina... Looking too build a fleet, or get a deal and flip it?
It sounds like you're doing your own survey. Makes sense on a low cost boat.
Impossible to tell from an image. You need to test the hull with a hammer (typical survey tool). Moisture meters can help if you understand their limitations.
If just flipping a boat, likely an extensive repair on a hull would not make the deal. If the boat has your eye and you are looking to commit to her, then the hull repairs and upgrading is more of a hobby for a DIY owner. Then the costs are less measured by the Benjamin's and more experience.
Never heard of rotten fiberglass. Typically, trailered boats will use the ablative type bottom paint, which sloughs off as the boat moves through the water. It is often common for boat owners to paint the existing bottom paint every year(or season). Thus you'll see a number of layers revealed if there hasn't been a repaint over a period of time. As long as their are no serious "blisters" (which is not a paint related issue) then you have a great opportunity to dress this boat out nicely for the cost of a gallon of bottom paint.
One comment though, your picture looks like just a view of the boat's bottom. Which is the part of the hull below the waterline. I'm I correct on that? Move back and take a picture of the hull from the waterline to the deck (this area is called the "topsides"). If the topsides appears to be the original gel coat finish, but is chalky or faded, it can be brought back to life quite handily by some light compounding and buffing. You can also do this for the cabin and deck areas that aren't non skid sections.
Finally, the non-skid areas on older boats will often have small cracks or "crazing" that can also be easily refurbished. That was the case on my boat, I used a product called Kiwi-grip that covered the old non-skid area with a roll on, textured finish, making it look brand new.
In summary, I think we're talking about cosmetic problems that are common fix ups. Of way more importance are structural issues, plus, sail, rigging and hardware condition. So make sure you address these things before making your purchase decision.
One comment though, your picture looks like just a view of the boat's bottom. Which is the part of the hull below the waterline. I'm I correct on that? Move back and take a picture of the hull from the waterline to the deck (this area is called the "topsides"). If the topsides appears to be the original gel coat finish, but is chalky or faded, it can be brought back to life quite handily by some light compounding and buffing. You can also do this for the cabin and deck areas that aren't non skid sections.
Finally, the non-skid areas on older boats will often have small cracks or "crazing" that can also be easily refurbished. That was the case on my boat, I used a product called Kiwi-grip that covered the old non-skid area with a roll on, textured finish, making it look brand new.
In summary, I think we're talking about cosmetic problems that are common fix ups. Of way more importance are structural issues, plus, sail, rigging and hardware condition. So make sure you address these things before making your purchase decision.
It is, however, important to note that fiberglass boats are particularly susceptible to severe damage from "polyester mites". Many of the top end manufacturers are now sheathing their fiberglass hulls with Burmese Teak.
It is hard to tell from the photo what that spot is all about. It is true that FG doesn't rot, but it can delaminate and exposure to moisture can make it worse. This does not look like delamination. The spot could simply be a discoloration from something that rubbed against the hull. You will have to inspect it in person to really tell what is going on. That said, you can repair almost anything on a FG boat.
Rotten fiberglass is just about the only potential problem you will not have on a fiberglass boat.
Decks can rot though, because they're a fiberglass and wood sandwich. Point to something on a sailboat, and most of the Sailnet forum members will be able to tell you what might be wrong with it.
Highly recommend you get a survey (as others have suggested). The purchase price of the boat is not the determining factor in whether you should have a survey. What the boat could cost you in repairs is the reason for a survey. A free boat can drain your wallet and your spirit as quickly as an expensive boat.
Decks can rot though, because they're a fiberglass and wood sandwich. Point to something on a sailboat, and most of the Sailnet forum members will be able to tell you what might be wrong with it.
Highly recommend you get a survey (as others have suggested). The purchase price of the boat is not the determining factor in whether you should have a survey. What the boat could cost you in repairs is the reason for a survey. A free boat can drain your wallet and your spirit as quickly as an expensive boat.
While I hesitate to express a differing opinion than John 
..... I do believe that a survey IS needed. And, the less expensive the initial cost, the more important it becomes. Some of us here are (more or less) qualified to do our own survey, but that is no real guarantee of a successful outcome either.
Besides the knowledge that the surveyor brings, there is a huge value to putting other eyes on the boat -- eyes that are not infatuated with the boat.
..... I do believe that a survey IS needed. And, the less expensive the initial cost, the more important it becomes. Some of us here are (more or less) qualified to do our own survey, but that is no real guarantee of a successful outcome either.Besides the knowledge that the surveyor brings, there is a huge value to putting other eyes on the boat -- eyes that are not infatuated with the boat.
Bottom paint degrades quickly under a strong alkali environment. I used to publish a homemade peelaway recipe on this site about twice a year but ... an even easier way is to use easy-off spray.
Spray this on the bottom paint you want to remove. Let it sit a day. Hit it with a pressure washer and it will sluff off to gel-coat. It is kind of remarable. The first time I tried this... all I could think of was the first four boats I owned and how I spent two solid weekends sanding.
Once the old paint is off...sand the few spots that stuck on (I never understood why a few spots are always chemically inert) fill in any gouges with fairing compound. If it were my boat, I would then cover the bottom with a 2-part epoxy barrier coat. I've purchased mine from J. T. Davis and I used a barrier coat for pools (doesn't say marine on the can so it is much cheaper) and then put a coat of ablative over the top of that.
I think @jssailem means Rubber mallet
Not
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,742
Tapping, or percussion testing, is an extremely useful non-destructive inspection technique.
I was suggesting something like these.
Definitely
Never used a rubber mallet. Doubt it will serve the intended use.
As so often is the case it is the craftsmanship and knowledge of tools to utilize that yields a solution.
I was suggesting something like these.
Definitely
the imaged Claw hammer.
Never used a rubber mallet. Doubt it will serve the intended use.
As so often is the case it is the craftsmanship and knowledge of tools to utilize that yields a solution.
His insurance company will require a survey, BUT they don't care if he gets the survey before or after purchase.
I tapped on that part and it doesn't feel soft or anything. It's probably just the paint. Just gonna sand it all off and re-paint it.
I'm planning on keeping this in saltwater. Is there a cheaper type of antifouling paint you would recommend?Bottom paint degrades quickly under a strong alkali environment. I used to publish a homemade peelaway recipe on this site about twice a year but ... an even easier way is to use easy-off spray.
View attachment 204291
Spray this on the bottom paint you want to remove. Let it sit a day. Hit it with a pressure washer and it will sluff off to gel-coat. It is kind of remarable. The first time I tried this... all I could think of was the first four boats I owned and how I spent two solid weekends sanding.
Once the old paint is off...sand the few spots that stuck on (I never understood why a few spots are always chemically inert) fill in any gouges with fairing compound. If it were my boat, I would then cover the bottom with a 2-part epoxy barrier coat. I've purchased mine from J. T. Davis and I used a barrier coat for pools (doesn't say marine on the can so it is much cheaper) and then put a coat of ablative over the top of that.
I think @jssailem means Rubber mallet
View attachment 204289
Not
View attachment 204290