1961 Glasspar G-3 gets a new Transom...

[andgott]

Although I JUST got my boat splashed, I'm already on the next project!!

This is not my boat. I'm doing it for a good friend of mine. He just acquired a 1961 Glasspar g-3 Speedboat. A prior owner had attempted to repair the transom, and did a BAD job of it... They obviously had no clue how to go about doing it- If only they'd have stopped by IBoats first... Oh well.

They cut out the bad section, including the outer skin, and put some plywood in it's place.

This is how it showed up this morning at my shop-

NOT a good repair- It really had no structural strength, it was kind of glued in place with resin all around. Frankly, I'm surprised that it held in place with a motor on it. The only thing to do is take it out, But first- I needed to pop the cap off, since there is really no way to access it properly in place. So, about 45 minutes after arrival-

I was able to salvage the rub rail insert, which will be good for the budget! There were about 100 rivets all the way around. I drilled the heads off, and poped 'em out. Then, a little strategic lifting, and the deck was off!

Prior to it's arrival here, someone had removed the bulk of the remaining plywood from the transom. I cut out the 'repair'- There was NOTHING usable there... It needs an outside skin!

Then, Some work with the grinder to get the rest of the wood off-

Now, I need to replace the outer skin, so I can build the transom back....

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

The G-3 transom presents a few challenges- One of them is the transverse curve. So, To replace the skin, I need a mold to form it... I used a sheet of 1/4" MDF, and an oak batten to form a mold over the outside of the transom-

The oak batten keeps the top curved correctly-

There is a layer of waxed paper attached to the MDF to keep the 'glass from sticking.

Now for a couple layers of glass-

Sorry, no photos of the layup itself- I don't like to touch my camera when I've got epoxy on my hands!

I used two layers of cloth so far. the first one was cut out to fit right inside the missing area. There is no strength to this layer, really- it just fills a 'void'. The next layer overlaps the edge of the repaired area by about 2" all around. I tapered the edges of the existing transom- so as I build up glass inside, it won't get too thick... In the end, I want the repair to be about the same thickness as the original skin.

After another layer or two in the repair area, I'll put a layer of Biaxial cloth across the entire transom... And then start with plywood.

Then come stringers. Then the floor.... What was I thinking

-Andrew

 

[Bamaman1]

Re: 1961 Glasspar G-3 gets a new Transom...

I'm not a fiberglass guy, but the subject is addressed time and time again on this Forum. Look to the bottom of this page for like sites. Transom repairs are very common. At least you have the bottom out so you can visually inspect the stringers at the same time.

My next door neighbor had a Glaspar G3 in the early 60's. They were a very unique, modern boat design--ahead of their time. With a 55 hp white Mercury engine, it performed very well. With a modern 75 hp motor, it'd be great.

Good luck.

 

[yabuoy]

Re: 1961 Glasspar G-3 gets a new Transom...

This is a great thread, thanks for all of the pictures. I will be looking at it as you continue as I get ready to rebuild my transom soon

 

[oops!]

Re: 1961 Glasspar G-3 gets a new Transom...

whaaaa hooo !

great job..........but what the heck is this epoxy stuff????

really nice to see a great job in progress.

cheers
oops

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

Thanks....

Ooops- It's kind of like your Poly but it doesn't stink so bad

 

[Woodonglass]

Re: 1961 Glasspar G-3 gets a new Transom...

I agree with the epoxy in this case. Since the PO was ignorant enough to cut the outer skin I think using epoxy to create the new one is a great idea due to the increased strength you will gain. I assume you will be painting the hull and not gelcoating??

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

I agree with the epoxy in this case. Since the PO was ignorant enough to cut the outer skin I think using epoxy to create the new one is a great idea due to the increased strength you will gain. I assume you will be painting the hull and not gelcoating??

Yeah, It'll be painted.

I use epoxy for pretty much everything- It is a little more costly, but to me worth it, I like working with it better. I tend to get bad headaches from the fumes dealing with poly... I've never had issues with Epoxies...

-Andrew

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

A bit more done this morning...

First, I got the templates made for the plywood... I used a nice, heavy sheet of paper that I cut CLOSE to the size I'd need, then I 'pressed' it in to the transom. The center line of the transom is marked w/ tape, and I work from there out. It's a pretty quick, and accurate, method... It took about 10 minutes to get a good pattern-

A little adjustment to the side, near the sponson-

Then, it was just a matter of flipping it over to make sure it fit the OTHER side, too- Which it did-

Then, I transferred it to Cardboard-

And, It fits... I didn't transfer the top profile where the motor well will be, since I need to figure out exactly where it will be.

After cutting the template, I laid down two more layers of glass-

The next layer will be a layer of biaxial cloth running all the way across the transom, from sponson to sponson... Then it'll be time to start with some plywood.

The slow part at this stage is waiting for everything to cure!! I might start tearing down the NEXT project in the mean time

-Andrew

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

A little bit more progress this afternoon... I used the FAST hardener this morning, and since it was a nice warm day, I was able to get a bit more glass work done-

There is now a layer of nice, heavy Biax across the entire transom, from sponson to sponson. There are 4 layers of 'glass in the repaired area, with an overlapping edge to tie it in to the old skin, and now an additional layer across the entire transom. This will provide a little more strength in the transom than the original had. The thickness of the repaired area is roughly the same as the old skin now.

The curve is held fairly well still, But might not be dead on. I'll pop the cap back on before I put the wood in, to make sure that I get the curve of the transom right- Once the wood is in, it won't be adjustable!

I'll be able to use clamps secured to the stringers to 'push' the transom out where I need it to be, as well as to clamp the plywood in place... This is a lot easier than my last restoration, where the stringers were completely gone...

Next step- PLYWOOD. Probably tomorrow. I need to get more epoxy, though!

Oh- I also started on my Lake N Sea... I get bored when I'm waiting for the epoxy to cure... There will be a new thread on that soon, too

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

Another productive morning...

One GREAT thing about working on a boat like the G-3 is that there are a lot of them out there- and a lot of them have already been restored. So, It's easy to find someone who's been there, done that... There are PLENTY of other peoples mistakes to learn from! The sponson area of the stern is one of the areas that I was unsure about, so I got some advice from those who have repaired them before.

This is one of those areas where you need to remember that you are not trying to build 1000's of these boats, as the manufacturer did initially, rather rebuild one in the most efficient, and most importantly STRONG and SAFE manner. For that reason, you may not be putting things back together in the same manner as it was initially built. The wood in G-3 transoms originally went into the sponson area on both sides, but I have found that many restorers choose to reinforce the ends of the sponsons with fiberglass, then close off the sponsons... Then, the transom is tabbed into the hull. The result is more strength in the transom, and the sponsons as well... It'll make sense as the work progresses, I promise!

Here is the area in the condition it was in when I got it-

It had already been cut open for some 'exploration', so that will need to be fixed.

First, A bit of cutting and grinding to make it all square... Then, I tapered the edge down so I have more surface area to join the new plywood to the hull-

A plywood 'patch' is cut-

The edge is tapered, like the cutout-

It fits pretty well... A little fine tuning, but it's close. It has already been sealed in epoxy, and I'll use some thickened epoxy to glue it in place, and then fiberglass over the top of it.

But, before I can close off the sponsons, I need to reinforce the sponsons a bit. I'm going to use 2 layers of 1708 Biaxial tabbed into the hull... The fiberglass will be over 3x thicker than the original here, so strength won't be an issue!

And, on the Port side (note that the cutout is missing from this side!!)

That should be plenty strong. The sponsons are sealed off completely, and offer additional floatation, so it's important that they stay intact!!

-Andrew

 

[Woodonglass]

Re: 1961 Glasspar G-3 gets a new Transom...

As usual very nice work and documentation of the process. This must be a really good friend for you to go to this amount of work. Where's dem pics of the Lake N' Sea???

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

I got the replacement plywood in this morning. I glued it in place with thickened epoxy. Once that cured, I ground it all flush, and got a few layers of glass on top-

I didn't have the 'real' camera with me, since epoxy and expensive electronics don't mix, so you'll have to just get by with an IPhone pic...

That's about all I'm going to get done 'till monday- I have to take my weekends off or the wife will start to complain. But, I got a lot done this week. Hopefully, I'll get the transom in next week- I just need my epoxy to get here, I'm almost out!

-Andrew

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

This morning, I cut the repaired area down to the proper height-

I used a strip of masking tape to mark the line, and cut away! I used one of those Harbor Freight oscillating tools- It did a great job... ANYONE working on a boat needs to have one of those handy!

After that, I cut some plywood to fit it in place. My template was fairly close, just needed to make some adjustments with the grinder. Once it fit, I needed to get the curve of the transom right-

The outside of the transom is supposed to be 3 1/2" from the yellow string- 3" from the inside corners of the boat, plus 1/2" for the plywood that's in there, too... It's CLOSE, but will need to be 'pushed out' a bit to be dead on.

I clamped a notched 2 x 2 to the stringer, to push the transom out where it needs to be.

And, it's right where I need it to be. I'll mark the 2 x 2 so I can re-clamp it easily when I epoxy the plywood in place.

The next step is to epoxy this layer of plywood in- BUT, I am out of epoxy! I've got an order coming, though...

IN the mean time, I'm going to get all the clamps, wedges, and other Misc. "stuff" I need together so I will be ready to roll once I get my supplies.

-Andrew

 

[Woodonglass]

Re: 1961 Glasspar G-3 gets a new Transom...

How/Where did you get the specs for the transom flex requirements.

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

How/Where did you get the specs for the transom flex requirements.

Had it been intact, I would have used the measurement from that... Since it wasn't- I had a couple of options... The EASIEST was to find someone who has one of these boats, and ask them. I was also able to verify that the transom height was correct. Since there are a lot of these boats out there, that was the best way to go.

If that wasn't a possibility, the other method would be to put the cap back on temporarily, check where the transom should be, and use that measurement.... By running a string from corner to corner of the transom, you get a nice straight line, and can measure off that to where the center of the transom should go.

Even with this measurement, I'll pop the cap back on there just to make sure before I make anything permanent!

-Andrew

Even if you

 

[Woodonglass]

Re: 1961 Glasspar G-3 gets a new Transom...

Good info. I thought maybe you had MFG specs or something, but good measurements prior to disassembly usually will give the answer but it all depends on the original condition. And then there's alway Fiberglassics.com.

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

My epoxy came today- So I could get back to work on THIS project. It's nice having two boats going at once, there is much less down time that way!

I had already dry fit the transom, and I cut some wood wedges to hold it in place while the epoxy sets-

I know that the transom is supposed to be 11 degrees from vertical when done, so I cut the ends of the 2 x 4's at that angle, then cut them about 1/8" longer than the distance between the transom and the stringer, and drove 'em home with a hammer. It is a nice, tight fit- But not TOO snug, because I've still got to get a layer of thickened epoxy in there. Once I was sure it all fit, and that I had all my clamps ready to go, I mixed up a nice big batch of epoxy. Sorry, no photos of this stage- Epoxy and expensive camera equipment just don't mix

I spread a good layer of epoxy, thickened with microballoons, on the inside skin of the transom, about 1/8" or so thick. Then, I installed the transom, and clamped it down all around, using the wedges on the bottom, and clamps on the top. I checked- and double checked- the measurement from the string across the back to make sure that the curve was right- Once this cures, there is no going back!

One layer down- Two more to go!

I SHOULD be able to laminate the next two layers at the same time- I didn't want to do more than one layer of ply this time, because I had a lot going on trying to get the curve & angle of the transom correct... But, once this cures, that will be set- And I'll have a lot less going on... I should be putting the rest of the wood in tomorrow.

-Andrew

 

[Woodonglass]

Re: 1961 Glasspar G-3 gets a new Transom...

Andrew, With all the transoms you do, why haven't you made a set of Transom Clamps? Just askin. I know your wedge system works. Have seen you use it in the past, but it seems to me, especially with curved transoms and irregular shapes, the transom clamps would make things a whole lot easier. Just my opinion.

 

[andgott]

Re: 1961 Glasspar G-3 gets a new Transom...

I actually find this method works better when you're trying to keep the curve of the transom right- I need something that applies outward pressure, and this does the trick... If you try to do it without something holding the curve, it tends to flatten the transom out. For subsequent layers of wood, once the curve is set, clamps woud be fine.