1964 Dorsett Catalina Transom Re-build

[pats]

Hello everybody,

I am about to start the process of replacing the transom, and probably the stringers and floor in my 1964 Dorsett Catalina. This will be the first time that I have done this type of work. I have a few questions before I start doing any cutting, hopefully someone will know the answers.

1st question(s) - I was told that to remove the transom plywood I will need to cut the floor back, because the stringers are attached to the transom. Is this correct? How far back should I cut the floor from the transom, I also need to inspect the stringers during this process. I don't really know what the layout or position of the stringers are, I have looked at several different photos but I'm still kind of cloudy about it. Do you think that a "handheld stud finder" would show the stringers through the floor, like it finds studs behind sheetrock? If anyone has photos of the stringers in a Dorsett Catalina would it be possible for you to post them. Which tool would you recommend to cut the floor with?

2nd Question(s) - I am lucky in that, I have a friend that lets me stay in his cabin during the summer, when his family isn't using it. However, its a small "lake cabin" that they don't use during the winter, because its not heated or insulated and they are afraid of freeze-ups. I have a annual camping permit for the State Park and I will continue the work there this winter. I will stay in the cabin of the boat at one of the campgrounds, its quite comfortable. I have two' 9000 BTU, "Buddy Heaters", one for the front cabin and one for the enclosed canopy area. I very seldom have to run these heaters on "high", maybe on a cold morning for a couple of hours, that's it. I guess my question is, how cold or at what temperatures can I use fiberglass resin? For instance, say its 29 F degrees outside, but inside the boat, in the enclosed canopy area where the transom is, its 65 F degrees. Can I wet-out fiberglass cloth with resin and have the resin cure as its supposed to? I have a couple of 12v oscillating fans to move the air around and maintain a more constant temperature. Hopefully, I will wet-out the fiberglass cloth during the warmer daylight hours, giving the curing process a few hours of warmer ambient temperature. The example I explained is during the nighttime, Do you think that I will be able to do the fiberglass work with a reasonable amount of success? Is there any advice or tips for doing fiberglass work in cold weather?

I intend to leave Wednesday, 10/3/18. I'll be going to Logan, NM. (near Tucumcari), and I'll probably stay about 10 days. I keep the boat stored there and use it on nearby Ute Lake. I'll be staying either at a friend's cabin or at Ute Lake State Park Campgrounds. I enjoy camping at this park during the winter, usually I am the only one in the campground. There are a few day-use visitors from time to time, but they generally don't stay long. Actually, staying in the boat is kinda fun, I have a small kitchen set-up, and the front cabin has color tv and I can pickup 16 OTA channels. "Free" OTA channels from Albuquerque, Roswell, 4 PBS stations from Portales, and some from Amarillo, plus I have a media player that I can use to play movies from a flash drive. So all in all, not to bad. I wish the park had Wifi so I could use the forum to ask questions while I'm there. There is however, Wifi at the Subway in Logan NM, about 15 miles away. I'll use it if need be. The elevation at the park 4200 ft. so it doesn't get to cold, but in the summer it gets very hot, 100 F +. I am including a few pictures so you can see what its like.

I look forward to your answers, and want to thank you for any responses or information.................Pats.

[Helmar]

Well, I will give you my

#1
I have been into the 1960 but the hull is different in the 64 so not sure. This is hard to explain without pictures, which I can't seem to find. Used too, we would have to open a exploratory hole in the floor. This used to be big enough to get you head/camera in but now with these little goodies, its just a half inch hole. They call it a Endoscope and works with a smart phone. Available on Amazon for like 20 bucks. Lets see if I can find it real quick. Oh my.....The one I got for 20 bucks is now 70 bucks. Still 2MP which is about all you need, use it for Lots of other projects, available on Amazon from about 15 bucks up.
I have never used a stud finder but can't see why that would not work. Normally they would use MDO Plywood for stringers. stringer comes up to the bottom of the floor and they run a strip of wood next to it to which because of the end grain top of the stringer, they would attach the top of the stringer to the strip of wood (something like 5/8's x 1" strip) and then they used Pallet nails to nail the floor down to the strips.. Find the row of pallet nails (or they may have used something different on the 64 like screws) Find them next to the front and real bulkhead and just snap a chock line or straight edge and draw a line down the rows of stringers so you know were they are.

On all the Dorsetts I have worked on, the stringers go all the way back to the transom.
I use a Panel saw to open up the floor with but a saw is a saw in a larger open area.

Lets say you open up a good size hole between the stringers. (here comes me trying to draw a picture with words) Say 12 x 12" Keep the cut out piece. Do the inspection ( I like the big hole as I can get my arm and punch down in and poke at the stringers looking for dryrot) Lets say the floor is 1/2" MDO plywood. Cut some 2" strips of plywood to use in the hole. I might have to draw a picture but a 2" strip, goes down in under the floor along the inspection cut out with 1" on the underside of the floor and 1" visible. Clamp it, use screws to attach it to the underside of the floor, screws down from the top side. Do this on all 4 sides of the inspection hole. All this is going to do is when you take your inspection cut out piece, you would be able to drop it back in the hole and it just not fall though the hold. Now fasten that would wood screws, some sort of filler (I use a epoxy resin mixed up with silica to make a peanut butter thickness of epoxy to fill the gaps and seal the end grain of the MDO plywood.

Now lets say the stringers are shot or close enough to the point they need replaced. If I remember right, the stringers stop at the cabin bulkhead, So, if the Cabin floor is OK and you need to replace the rear it can be done in two ways. You need that splashwell out of the way. I can add the pictures of were the cuts are made, Important, you can See the underside of those cuts as to use fiberglass Matt or Cloth to close the hack saw blade width gap..
The other option, older way was to split the boat by pulling the cabin top off the hull so you are totally open and can do Everything with ease. This is not as hard as you think. Just time and a bunch of screws or rivets to pull or drill out.

Never the less, for the transom, the rear splashwell has to come out as the transom goes all the way down to the hull and normally is a keel brace between the keel and transom as a stiffener. Again, once you see it, not hard to reproduce. Fiberlay has everything you could ever need to save these old girls.

#2.
I have done the fiberglass when freezing, but, got it down and started the cure Before the freezing cold. It will still kick and cure but takes longer. The warmer the faster it kicks and cures.
Propane heaters pump out a lot of moisture which is not good on the resin but heating the hull from the outside would work. Still, the heat of the day I would do the process.
Everything is cut to fit. First is on the inside of the transom needs to be at least 70% clean glass. Always try for 100% clean fresh fiberglass. 10oz pot of Fiberlay P-16 Laminating ! Resin is what I use for the first layer as I resin up the transom, lay the fiberglass matt onto the transom, slop and saturate the matt, put your first layer of marine plywood in place, clamp, screw, whatever it takes to mash that plywood to the transom so the resin is squishing out (protect the Outside of the transom with plastic and plenty of tape, the insides, let the excess just run down onto the hull, clean or not. if its going get in the way of the next layer, wipe it off)
So this is done the heat of the day,. Curing of each layer might take two nights before you pull the screws and clamps off it.
I myself will build out the transom to at least 2" thickness as All the new motors have more torque the smaller motors used back in 1964.
You will have to trim the back edge of the fiberglass splashwell for the thicker transom. Done with a osolating saw, not hard, draw a line and stay on the line or you have more filling and fairing to do.

I just went back over what I wrote and you had better just call me. Email me your phone number and what time to call. helmar@classicboatclub.com

This was just for the transom, so lets say the stringer are gone or close to gone (should be Close to gone due to her age)
How I do this process is not hard.
But lets see if I can explain this process.

If you pull the floor and have to replace the stingers, you have several options. One if the MDO is still good enough, you can use Fiberglass Roving with is the heavy weave. Its what all the Skagit boat have done as all of them have Fiberglass stingers in them. You can just Fiberglass the Roving to the MDO but at the top, they will need to be trimmed down as that is were the fiberglass will need to be curled over. Two part process, call me on that one.

But most of the time the big question, How to I get all these stringer Flat for the floor to go down on..
If you are doing this on a Trailer and not on a Flat concrete floor, once you pull all the wood out and your just staring at the open hull, you need to make sure that you have NO twisting because of the way she is sitting on the trailer.
I do this with a spinning laser. I mount the laser on the transom, shoot a line right up the keel. (I do this before a take the floor up or stringers out) I know were the floor meets the cabin bulkhead and the transom, mark them Good, notch or whatever so you don't loose track of where they are.
That is were you set you Level line so your laser beam is level with the floor. It can be 6, 8 12" or whatever Above the floor but yet the same forward and aft.

This gives you your level line of the floor forward and aft. Now for the port and starboard.
On the transom, I would measure down to the Chine edge of the boat, or any groove or mark that you know is the same port and starboard. Might even measure out from the keep to make sure the mold didn't slip when it was laid up. Slipping is not uncommon at all. I have found the port and starboard chine edge up by the bulkhead as much as 1/2 inch different..Sitting on a trailer, it could be even off more.

So what you are looking for with the spinning laser (does not have to spin, just even turn from side to side like a attaching laser level) the same distance above the floor forward and aft, Then the same distance port and starboard from the floor.

With the laser set that way, you have have a laser line to measure down from. If the laser line is say even 18 inches above the floor, you got it, The top of the floor would be 18" down from that laser line. Same port and starboard.

Does any of this help or scare you away from it....Its really not that hard to do. Well, its is time consuming.

Helmar