Barnacle damage or zebra muscles?

[Avoegeli]

New to me JJ Taylor Contessa 32. Spent its life on the Great Lakes. I noticed some pitting that looks like has red epoxy in. It's in the boot stripe or whatever line that is (the water line) also a bunch of small visible circles that are slightly raised to the touch. Just in that first stripe above the epoxy barrier? I assume that's an epoxy barrier from manufacturer. Grey in color just under the VC 17. It looks like it's barnacle damage. Could it be osmosis? Always pulled out of water for winters. Doesn't seem right. Here are aime oics

[Avoegeli]

Wider shot sorry

[fstbttms]

Barnacles and mussels don't do that.

[rslifkin]

I've had a few spots like that just above the bottom paint on my transom. Basically the gelcoat just popped off in a couple of tiny spots. No detectable adhesion issues or blistering around the spot and the underlying fiberglass looked fine. So I just faired them back in and haven't had any new ones.

[Franziska]

Originally Posted by fstbttms

Barnacles and mussels don't do that.

Not even when someone scrapes them away in a forceful way?

The photos look to me like there were some attached and when removing them it took a piece of antifouling away at some of their attachment spots.
The location at the waterline supports that theory too, exactly where stuff like that likes to grow. Good levels of light and oxygen.
So the mussels might not to it, but their removal might do.

I suspect that the red is paint from an old boot stripe, which had been painted over with antifouling, when someone raised the antifouling to a bit above the waterline.

Does not look like osmosis to me.

Fill in with epoxy and reapply antifouling.

[fstbttms]

Originally Posted by Franziska

Not even when someone scrapes them away in a forceful way?

Nope.

[PerfectPirate]

First off, we don't get barnacles in the fresh water of the Great Lakes. We do get Zebra Mussels, thanks to international shipping, but they do not have this kind of effect on gelcoat.

So what is the issue? To me it looks like simple, and not terribly serious, osmosis. I had a similar issue on my current 1975-vintage boat. Like your boat, mine had been protected with an after-market application of Interprotect 2000. That's the grey epoxy below your waterline, under your bottom paint. However, boats sit slightly deeper in fresh water than in salt water. Also, as they age, they absorb moisture and get loaded with more and more gear, so they sit even deeper. It is not at all unusual for some part of the bottom edge of the boot stripe to end up submerged when sitting in the slip. On each of my last three boats, I have raised the waterline by two to three inches when I applied new Interprotect barrier coats.

As the gelcoat sits immersed, a certain amount of water can penetrate it. Polyester is not waterproof, just water-resistant. As the water molecules penetrate, they gather into any voids which they may find in, or behind, the gelcoat. When the boat is hauled out for winter and that water freezes, it expands and makes the void larger. When the boat is relaunched, more water penetrates and the vicious cycle is perpetuated. Eventually, visible blisters form on the surface. If you open them up, there will be a viscous discharge and a noticeable void, as seen in your pictures.

The solution is to open up any detectable blisters, let them dry out over a period of months (ie. the winter), and then fill them with thickened epoxy. Then add on to your Interprotect barrier coat by extending it up higher on the hull, to cover the area which has been blistering. Interlux and West Systems (the epoxy people) have a great deal of literature available on dealing with osmosis and effecting permanent repairs. You can find it easily on the internet.

Many of the boats built in the seventies and eighties were prone to osmosis, before reputable builders switched to vinylester gelcoat, which is more water-resistant. Many of these old boats have been protected, like yours, by the application of after-market barrier coats, such as Interprotect or Pettit High-Build Epoxy. However, a key issue is how thorough and committed was the owner who applied the epoxy. Many owners attempted to save time and money by skimping on preparation work, or on the number of coats applied (this stuff is expensive!), and therefore did not build up a layer sufficiently thick to provide adequate protection. That was an issue on my last two boats, requiring me to sand off the inadequate epoxy layer and apply a sufficiently thick barrier coat. However, once applied properly, my boat bottoms have given no trouble over a period of decades.

[Franziska]

The reason I doubted that it is Osmosis are the orange encircled areas.
To me that looks like some sort of creature had been attached there.

Unless, I misinterpreted the image.

Are these actually raised spots? (From the image I thought they are flat.)
If they are raised, than they are bubbles. Open one up, if it's wet and smells acidic it is Osmosis after all.
In this case open them up with a Dremel, wash thoroughly and let it dry for a long period. Once they are completely dry, fill with epoxy, remove antifouling and put at least 2 layers of barrier epoxy coat on before applying new antifouling.
Attachment 272632

[Avoegeli]

Originally Posted by Franziska

The reason I doubted that it is Osmosis are the orange encircled areas.
To me that looks like some sort of creature had been attached there.

Unless, I misinterpreted the image.

Are these actually raised spots? (From the image I thought they are flat.)
If they are raised, than they are bubbles. Open one up, if it's wet and smells acidic it is Osmosis after all.
In this case open them up with a Dremel, wash thoroughly and let it dry for a long period. Once they are completely dry, fill with epoxy, remove antifouling and put at least 2 layers of barrier epoxy coat on before applying new antifouling.
Attachment 272632

Upon further inspection the circles I thought were raised to the touch are slight depressions. The red spots are actually where the depression went all the way through to that red paint or epoxy or gel coat. They are all dimples. The red ones being the worst and the deepest. Still not into fiberglass so I can't mahone it's osmosis. Rest of hull is pristine. What video I see on YouTube of osmosis is usually below the water line and they are always on boats with layers and layers of paint. And they are never in tight connected circles which look like the outline of barnacles or crustaceans that adhered to hull. Is the area I'm calling the boot stripe, the area in question, actually the boot stripe? What's the thin blue line above that? I've included another picture that shows a little more surface area

[Franziska]

Hmm, this is a bit of a riddle.

For how long has the boat been out of the water?
If it has been quite some time, it could be dried out blisters, which would be Osmosis after all.

Take a cutter and cut one open cross wise.
Peel it open. Any crystals visible? Does it smell acidic?

[PerfectPirate]

Originally Posted by Avoegeli

What video I see on YouTube of osmosis is usually below the water line and they are always on boats with layers and layers of paint. And they are never in tight connected circles which look like the outline of barnacles or crustaceans that adhered to hull. Is the area I'm calling the boot stripe, the area in question, actually the boot stripe? What's the thin blue line above that? I've included another picture that shows a little more surface area

In my previous post, I was indirectly trying to point out that there is often a difference between design waterline and actual waterline, and the actual waterline may end up well up onto the boot stripe. Incidentally, the term boot stripe refers to the one or more contrasting stripes which run just above, and parallel to, the waterline. So your boat has a broad boot stripe, with a narrow boot stripe above it. However, I am a bit confused. In your overall pictures of the boat, the broad stripe appears to be blue. In your close-up pictures, it appears to be black. Has it been over-coated with bottom paint? In any case, there appears to be a buildup of bottom crud on the boot stripe just forward of the problem area, which would indicated that it has been spending time submerged.

On my current boat, the actual waterline had moved a good one to one-and-a-half inches up above the design waterline, as indicated by the boot stripe. My boat was an early hull in the production run and I have noticed that on later hulls the builder moved the waterline up by about two vertical inches. Also, you keep talking about barnacles and crustaceans, even though you say that your boat has spent its life in the fresh water of the Great Lakes. I have been sailing and scuba diving on the Great Lakes for 55 years and I have never seen a barnacle or crustacean on either a hull or a dock. Slime yes, seaweed yes, but never a barnacle. We do have zebra mussels now, but they are a relatively recent phenomenon and do not do this kind of damage. I have cleaned enough of them off of bottoms in the past few years to be sure of that.

Osmosis, and pre-osmotic conditions, take various forms, not just big bubbles in the fiberglass. The term 'osmosis damage' simply refers to the process of water penetrating and being trapped behind the gelcoat. Typically, the osmosis pictures on the internet are of the most dramatic cases, usually ocean-going boats which have not been out of the water for years, so that the osmosis is well advanced before being detected. I am attaching a couple of pictures of the gelcoat on my boat, taken during the repair process. They show a pre-osmotic failure of the gelcoat, in which the gelcoat itself has cracked, but water has not yet managed to penetrate and form blisters behind the gelcoat. The first picture shows a number of circular faults along the boot stripe, which has been sanded off. This is above the design waterline. Above the boot stripe, the hull is pristine, with no cracking or stress fracturing. The second picture shows where I have ground open the faults using a burr bit on a rotary tool, through the gelcoat down to the actual fiberglass. These pits were then filled in with thickened epoxy, prior to being covered by a new barrier coat. Although the second picture shows a portion of the hull which is below the waterline, the fracturing was much more prevalent along the old boot stripe, which was theoretically above the waterline. This is because the submerged portion of the boot stripe was above the inadequate barrier coat that had previously been applied. Although it was not properly prepped, nor thick enough for proper protection, it still provided some protection from water penetration of the gelcoat. My new barrier coat is much thicker and extends the waterline up to the top of the original boot stripe. I will be painting a new boot stripe above that. The third picture shows that same area of the bottom before I ground open the faults. You can see a similarity to your own areas of concern.

A final point: two coats of epoxy barrier coat is considered to be enough ONLY if you are using Pettit High-Build. If you are using Interprotect 2000, which is what appears to currently be on your boat, you need to apply six to eight coats, in order to guarantee the essential 10-mil thickness. That is where many owners cheap out. Or they try to stretch out the epoxy by rolling each coat too thin. To do all of the extensive repair and prep work only to cheap out on buying sufficient materials makes no sense. To adequately protect the bottom of my boat required five gallons of Interprotect 2000, which was $1,000 worth of materials. Given the months of work to remove, repair and prep, there was no way that I was going to cheap out at the end.

[Nicholson58]

Lots of good advice above.

Is it possible the hull was previously red and you are experiencing separation of the outer layer? Kind of looks like a bad paint job.

You probably will need to remove paint to the gel coat layer and apply new Interprotect 2000

[double u]

"...zebra muscles..."
gee, & I thought I knew a thing or two about marine fouling & bodybuilding...

[garyfdl]

Looks like 'boat-pox' to me...

As previously stated, barnacles aren't a problem in freshwater. And in the ~25 years zebra/quagga mussels have (occasionally) been showing up on my boat, they haven't caused any damage.

[Avoegeli]

Originally Posted by PerfectPirate

In my previous post, I was indirectly trying to point out that there is often a difference between design waterline and actual waterline, and the actual waterline may end up well up onto the boot stripe. Incidentally, the term boot stripe refers to the one or more contrasting stripes which run just above, and parallel to, the waterline. So your boat has a broad boot stripe, with a narrow boot stripe above it. However, I am a bit confused. In your overall pictures of the boat, the broad stripe appears to be blue. In your close-up pictures, it appears to be black. Has it been over-coated with bottom paint? In any case, there appears to be a buildup of bottom crud on the boot stripe just forward of the problem area, which would indicated that it has been spending time submerged.

On my current boat, the actual waterline had moved a good one to one-and-a-half inches up above the design waterline, as indicated by the boot stripe. My boat was an early hull in the production run and I have noticed that on later hulls the builder moved the waterline up by about two vertical inches. Also, you keep talking about barnacles and crustaceans, even though you say that your boat has spent its life in the fresh water of the Great Lakes. I have been sailing and scuba diving on the Great Lakes for 55 years and I have never seen a barnacle or crustacean on either a hull or a dock. Slime yes, seaweed yes, but never a barnacle. We do have zebra mussels now, but they are a relatively recent phenomenon and do not do this kind of damage. I have cleaned enough of them off of bottoms in the past few years to be sure of that.

Osmosis, and pre-osmotic conditions, take various forms, not just big bubbles in the fiberglass. The term 'osmosis damage' simply refers to the process of water penetrating and being trapped behind the gelcoat. Typically, the osmosis pictures on the internet are of the most dramatic cases, usually ocean-going boats which have not been out of the water for years, so that the osmosis is well advanced before being detected. I am attaching a couple of pictures of the gelcoat on my boat, taken during the repair process. They show a pre-osmotic failure of the gelcoat, in which the gelcoat itself has cracked, but water has not yet managed to penetrate and form blisters behind the gelcoat. The first picture shows a number of circular faults along the boot stripe, which has been sanded off. This is above the design waterline. Above the boot stripe, the hull is pristine, with no cracking or stress fracturing. The second picture shows where I have ground open the faults using a burr bit on a rotary tool, through the gelcoat down to the actual fiberglass. These pits were then filled in with thickened epoxy, prior to being covered by a new barrier coat. Although the second picture shows a portion of the hull which is below the waterline, the fracturing was much more prevalent along the old boot stripe, which was theoretically above the waterline. This is because the submerged portion of the boot stripe was above the inadequate barrier coat that had previously been applied. Although it was not properly prepped, nor thick enough for proper protection, it still provided some protection from water penetration of the gelcoat. My new barrier coat is much thicker and extends the waterline up to the top of the original boot stripe. I will be painting a new boot stripe above that. The third picture shows that same area of the bottom before I ground open the faults. You can see a similarity to your own areas of concern.

A final point: two coats of epoxy barrier coat is considered to be enough ONLY if you are using Pettit High-Build. If you are using Interprotect 2000, which is what appears to currently be on your boat, you need to apply six to eight coats, in order to guarantee the essential 10-mil thickness. That is where many owners cheap out. Or they try to stretch out the epoxy by rolling each coat too thin. To do all of the extensive repair and prep work only to cheap out on buying sufficient materials makes no sense. To adequately protect the bottom of my boat required five gallons of Interprotect 2000, which was $1,000 worth of materials. Given the months of work to remove, repair and prep, there was no way that I was going to cheap out at the end.

Thank you so much for all of this knowledge. Once I repair this damage can I move the barrier coat up so it encompasses the original water line boot stripe? Build that up to current thickness of barrier coat then add coats to achieve complete thickness? I guess I keep saying barnacles because I now keep the boat on the Hudson River and I cleaned some off when the boat hauled out for winter. And to answer your question about the stripe that you said looked black is gel coat not bottom paint. Bottom paint only ever went up as far as the barrier coat.