Typhoon Weekender #1508 - Hull gelcoat replacement

[Shinok]

We bought #1508 a few weeks ago. She had been on the hard sitting on her trailer for about 10 years out of the water. Since the boat had been on the hard for so long, we figured it was as dry as it was going to ever be and it would be a decent idea to barrier coat the hull before we start sailing her. In the interest of doing that, I started removing bottom paint and noted the gelcoat was in really rough shape. We knew there were spots on the hull that were bad, but it turned out the entire hull was a problem and some of it was just obscured by the bottom paint, more on that later.

To start with, we tried using TotalBoat TotalStrip on the hull to remove the bottom paint. I applied it per the instructions and applied plastic sheeting on top to prevent it from hardening. While it allowed us to strip the paint somewhat, it left a bit to be desired on how much was actually left:



You can see where there is a spot there where the gelcoat had holes all throughout it. I'm not sure if someone tried to sandblast the bottom paint off at some point, but there were several places like this on the hull we were aware of. At any rate, you can see how much the TotalStrip removed there. I was a bit disappointed with this, mainly because it still required a fair bit of grinding, but more importantly, I tried a bit on deck and it destroyed the gelcoat on the deck:



Now to be clear, the holes in the gelcoat you saw above were there before we applied the TotalStrip and we only used the TotalStrip on a small section of the hull before abandoning it. My point here is to exercise caution if you are using this stuff on your boat, it will destroy the gelcoat if left long enough and that is not something that is really readily documented. That said, the issues with the gelcoat on the hull existed prior to using TotalStrip.

From here, I started grinding away bottom paint only to find the gelcoat along the entire length of the hull was cracked and flaking off:



Either it had those holes in it or it was cracked. The holes were evident when we bought the boat, although I had expected that like in previous boats we've had, it was improper installation of bottom paint over the years and wasn't a big issue. Even if it was, there were maybe 3-4 spots on the boat that had them and I figured it was an easy enough repair. Unfortunately, there was more lurking below the surface as you can see here:



These cracks were filled and faired by the bottom paint, they were not visible at all until I started grinding away at the hull. As I took off the bottom paint, the cracks became visible. In some cases, I could just pull pieces off with my hand, so it wasn't bonded at all. After discussion with some friends that had dealt with this, I figured the solution was to remove all of the gelcoat, fair with colloidal silica, barrier coat with Interprotect, and then bottom paint.

The challenge for me was doing this in my yard. I live in the mountains an hour from our sailing destination and there are no boatyards within a reasonable distance. I also couldn't justify the cost to rent a peeler and I'm not sure it would have worked anyway give the tight spaces I had to work around on the trailer. I did what I had done in the past with this issue: a Makita GV5010 grinder w/ a soft hook/loop attachment and DustBuddie shroud to capture the dust.

Unfortunately, the shroud posted a problem on such a small boat, it was difficult to work into tight spaces without gouging the hull. About halfway through, it also stopped gripping the grinder properly and would work it sway towards the disc. I had to just deal with it, but that is not an issue I recalled having with previous models. It still did a decent job of capturing dust and as I pointed out in another thread, I went through 4 large shopvac bags and 4 HEPA filters trying to get all the remaining bottom paint and gelcoat off.

The result was....OK:


You can see where the grinder hit a few spots, although it looks MUCH worse in the photos than it actually is. You can really start to tell how good of a grinding job you did once the fairing compound is down, because the white spots fill in any flat areas and you can see where it dug in too much. You can also feel it with your hand, but every photo I've taken looks like I went hog wild with it and it's flat everywhere, it's not. Thankfully, my bladesmithing experience helped a bit here and I knew to take it slow and gentle, so I never went past the first layer of laminate anywhere on the hull, there were just some minor divots or flats in spots that were trickier to work.

After applying the epoxy, which I'll cover in the next post, you can start to look in the reflect of the epoxy off of a light source and see if it is faired out properly and smooth or not.

[Shinok]

For fairing, I noticed two things:

1. I needed to fill in any flat spots or divots made while grinding off the gelcoat
2. There were these small holes along the top of the waterline (and a few below) that needed filled, sortof like this:



My original thought was that these were evidence of blistering but grinding them out didn't really support that, maybe they are just spots where the resin had bubbles in them and never cured properly? I also noticed that in spots it appears that they had faired out portions of the hull with resin over the outer layer of cloth, these took on a much darker color and were harder when grinding.

I used some plastic spreads to spread the epoxy along the hull:


I had a larger metal fairing block of sorts, but found it hard to work with on the areas it was needed most. The plastic ones were more flexible and I had 3 sizes to work with. What I would do is use the middle size to apply the epoxy in large quantities around some areas, then use the much larger/wider one to try and fair it out a bit. It seemed really critical to lay the spreader down at <45 degree angle, if you had it positioned higher than that, it wouldn't spread or fair properly.

I started out being really diligent about scraping off the epoxy while working it to avoid excess, but I found that this wasn't properly filling in the flat spots, only the holes. For 80% of the hull, this was fine, but there were places I needed more epoxy on the hull to fill in flat spots from the grinder. This is where laying it down much closer to the hull and ensuring I had plenty of epoxy on the spreader and hull helped fill these spots. Unfortunately, it was also really difficult to keep these areas smooth using just the spreader, so I have to accept that during the sanding process, some spots will just require more sanding to be faired out.

You can see the end result here:



You can see the streaks left by the spreader. I just accept that I'm going to be sanding until my arm falls off smoothing those out, but that it's ultimately better that the flat spots and divots are filled and my arms get buffed up. Let's face it, i need the exercise anyway.

In the next photo, you can see where I messed up with the grinder, as this was nearing the end of grinding and my arm fatigue + issues with the shroud kinda made me get a bit sloppy. If you look along the keel, you can see some divots from where it dug in or I had stubborn spots to remove:


They look indented but are actually filled by the epoxy/silica mixture. This is where using more epoxy than you really want to helps and laying the spreader flat, if you don't then those spots will still have some indentation in them. There are a few places I'll be sanding down and re-applying as a result.

My plan from here is to use a pneumatic sander I have and try to wet sand at a very slow RPM to fair out everything. There are at least 3 or 4 sections (maybe 1x1 ft each) where I need to revisit because there wasn't enough epoxy down on the hull and it didn't fill properly. From there, I'll apply the first layer of barrier coat, which I expect will reveal more spots needed additional fairing to be smoothed out, as it's a bit hard to see with the epoxy down what spots are filled and which ones aren't. Once that is done, we'll finish with the barrier coat and bottom paint.

The logical question from here is also what I plan on doing about the spots covered by the trailer (bottom of the keel)...just doing what I can. I do not have access to a forklift or boatyard, so my plan is to finish other projects and have these done at a proper yard at some point in the near future. I worked it as low as I could without risking damage to the trailer, so I have to kindof accept the 90% for now. For the jackstands, I can get pretty decent coverage because our driveway has a slight incline, so I can tilt the boat temporarily and work under the stands and do what I can there (don't worry, there is still very little pressure on the jackstands when this happens)

[Shinok]

One thing to clarify: The epoxy covers the entire hull, but except for spots where there is a flat spot or something else, it remains very thin. Using an 80 grit on the grinder ate through it in less than a second. So I tried to not leave an excess on the entire hull, rather use the excess to fill spots where needed, which will then all be faired smooth in the next phase. It was a real careful balance of making sure you are using enough and not removing it from flat spots where it is needed to fill/fair.

[s2sailorlis]

Looks like blisters possibly. But they’re probably dried out since you’ve been on the hard for years.

[Carl Thunberg]

I did this exact project on a Rhodes 18 on a trailer in my driveway. On mine, the problem was the topsides too, so consider yourself lucky. You're on the right track. It's a lot of work to make it look good. Don't get too hung up on the few flat spots, since it's below the water line and won't be seen. Don't skimp on the barrier coat. Topsides are another matter entirely. This brings back bad memories of fairing boards and aching arms.

[wikakaru]

...

The logical question from here is also what I plan on doing about the spots covered by the trailer (bottom of the keel)...just doing what I can. I do not have access to a forklift or boatyard, so my plan is to finish other projects and have these done at a proper yard at some point in the near future. I worked it as low as I could without risking damage to the trailer, so I have to kindof accept the 90% for now. For the jackstands, I can get pretty decent coverage because our driveway has a slight incline, so I can tilt the boat temporarily and work under the stands and do what I can there (don't worry, there is still very little pressure on the jackstands when this happens)

Tip: The guide boards on the trailer can be removed by removing the lag bolts that hold them in. This will give you access to everything except the very bottom of the keel. Then use a hydraulic jack and blocks under whatever portion of the keel hangs off the trailer keel board to jack the boat up. Raise the trailer jackstands as you slowly raise the boat. I have a Triad trailer on my Typhoon and did it this way. The jackstands are strong enough to support the boat by itself, or they are on my Triad trailer, at least. The only tool required is the hydraulic jack, and they are relatively inexpensive if you don't have one.

Good job!

--Jim

[Shinok]

I did this exact project on a Rhodes 18 on a trailer in my driveway. On mine, the problem was the topsides too, so consider yourself lucky. You're on the right track. It's a lot of work to make it look good. Don't get too hung up on the few flat spots, since it's below the water line and won't be seen. Don't skimp on the barrier coat. Topsides are another matter entirely. This brings back bad memories of fairing boards and aching arms.

The side hull looks like it was done with Awlgrip some time ago, I know the previous owner didn't do it, so it's probably 25+ years old. It doesn't look great but it isn't awful, either. It's not cracking, at all, so I am probably going to leave that alone for now.

The decks are another story. The nonskid surfaces are cracked, but they aren't as dramatic or prolific. A previous owner went over it with some kind of primer and paint that has since cracked, so I plan on removing all of this and doing something about it there. My original plan was to remove all the gelcoat from the deck also and fair it, but I don't think it's necessary, I've been removing the single part paint on there now in large sections and the gelcoat outside of the non-skid surfaces looks pretty decent, the paint that was used is cracking and pulling apart far more in some spots, but the underlying gelcoat is fine.

I haven't decided what I'm doing about the decks yet. I'm currently more focused on the functional parts, like the bottom and cleaning up the deck hardware that was bedded with silicon, the latter of which has been a job in itself, but our last two boats had a lot of old silicon bedded hardware so it's not something I'm unfamiliar with, just tedious. I'm replacing all the bolts and backing plates with glass plates at the same time, which I think is necessary on any boat this old.

After washing the blush off, I went back over the hull and it looks like there is only one area where there are any flat spots, so I'll probably go over it again and leave the rest. It was the only spot I was being too conservative with the epoxy and it didn't fully fair out, the rest looks really smooth.

Looks like blisters possibly. But they’re probably dried out since you’ve been on the hard for years.

That was my initial thought, but I ground one set out and it didn't look like there was any evidence of blistering at some point. It's certainly possible, but I didn't see any indication that was the case below the first layer of mat.

Tip: The guide boards on the trailer can be removed by removing the lag bolts that hold them in. This will give you access to everything except the very bottom of the keel. Then use a hydraulic jack and blocks under whatever portion of the keel hangs off the trailer keel board to jack the boat up. Raise the trailer jackstands as you slowly raise the boat. I have a Triad trailer on my Typhoon and did it this way. The jackstands are strong enough to support the boat by itself, or they are on my Triad trailer, at least. The only tool required is the hydraulic jack, and they are relatively inexpensive if you don't have one.

Thanks for the info.

I considered doing this very thing, but the portion of the keeling hanging off is scary close to the shoe for the rudder and I was hesitant to risk putting too much pressure on it. I also considered removing the boards and may still, I'm trying to tackle the larger portion of it at this point. The gelcoat lower down surprisingly is less of an issue, but I'd like the whole thing to be uniform while I'm at it. I can't do any more grinding of bottom paint or gelcoat until I repair the shroud, which I'm gonna try to do this weekend, then see how to tackle the sections I couldn't reach earlier one by one. Good to know this is viable though, I had considered it but wasn't totally sure.

[Dick Villamil]

Have you tried a random orbital sander with 60 or coarser grit for the final sanding. Works better than a grinder but uses a lot of discs! I borrowed several short jack stands from the local marina to elevate the Typhoon off the trainer so as to work on the keel and then add 3 coats of barrier coat. Just be careful where you position the stands - place them where there is a bulkhead since they will cause oil canning of the bottom (which comes out after the boat is back on the trailer). Good idea to not put pressure on the brass skeg. Eager to see the finished project!

[wikakaru]

I considered doing this very thing, but the portion of the keeling hanging off is scary close to the shoe for the rudder and I was hesitant to risk putting too much pressure on it. I also considered removing the boards and may still, I'm trying to tackle the larger portion of it at this point. The gelcoat lower down surprisingly is less of an issue, but I'd like the whole thing to be uniform while I'm at it. I can't do any more grinding of bottom paint or gelcoat until I repair the shroud, which I'm gonna try to do this weekend, then see how to tackle the sections I couldn't reach earlier one by one. Good to know this is viable though, I had considered it but wasn't totally sure.

My boat was situated on the trailer in such a way that I was able to jack from the front of the keel, and I had the forethought to grease the jack stands prior to putting the boat on the trailer so that I could actually jack the aft part of the boat up with the just the jack stands without help from the hydraulic ram. If the jack stands are rusty and ungreased I doubt you could do this. I think the way the rudder shoe is built you could probably jack the boat from the shoe as long as you stay clear of the rudder itself. The boat "only" weighs 2,000 lbs. I don't remember exactly how the bottom keel board is attached to the trailer. Perhaps you could cut away a bit of the forward part, or use a hole saw somewhere in the middle to cut a jack-sized hole there and jack the boat up from the center of the keel.

--Jim

[wikakaru]

Just a long overdue follow-up...This is the trailer from my CD22 with the keel guide boards removed (left) and in-place (right). Fortunately when Triad built this trailer they used lag bolts that were easily accessible. My older Triad Typhoon trailer has the boards through-bolted and they can't be removed this way when the boat is on the trailer.

2023-07-07 Trailer guide boards before and after.jpg (217.5 KiB) Viewed 1802 times

Smooth sailing,

Jim