TOPIC: Glasspar G-3 gets a new transom...

I just started the next project. This isn't my boat, I'm doing this for a friend...

He just acquired a 1961 Glasspar G-3. It is in decent shape, but a previous owner really did a number on the transom in an attempt to make a repair-



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. The only thing to do is take it out, But first- I needed to pop the cap off. 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....

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

Afternoon Andrew,

Thanks for sharing the step by step of your repairs. I'm sure I'm not the only one who appreciates seeing how you're doing this rebuild.

Isn't it amazing how some people do things without a single thought to the outcome? The "repair" (using that term loosely) had no strength, as you stated. I guess the last owner thought the engine was going to hang on by magic. I am a firm believer that people like that should have their picture posted at every place you can buy tools and be denied entrance.

Glad to se your friend brought it to you and has the confidence to know you'll do it right.

hey guy just , curious seeing that you are using Epoxy , what fabric are you going to use ,and are you going to cut out... any more of the stringer system ,and if not........ are you going to use a scarf joint to splice in the the new wood for the stringers. Another quick question , and that is........ were there any knees in the boat to support the transom , and if not are you going to throw some in ?

OFFSHORE GINGER wrote:

hey guy just , curious seeing that you are using Epoxy , what fabric are you going to use

I used woven cloth for what I've done so far, will go over the entire thing with stitched Biax...

and are you going to cut out... any more of the stringer system ,and if not........ are you going to use a scarf joint to splice in the the new wood for the stringers.

The stringers are intact beyond what was missing when I started, so I don't plan to remove anything further... I'll either use a good scarf or 'sister' the new pieces in well... I'll probably use ply to replace them, like I did in the last couple I did. It's too damn hard to find good wood around here!

Another quick question , and that is........ were there any knees in the boat to support the transom , and if not are you going to throw some in ?

G-3's didn't have knees in them- I don't think that they're really required in the design. The stringers are pretty deep back there- The center stringer is almost 6", on a 15" transom, they offer great support for the transom.

Andrew , did you know that Woven roving is not compatible for use with Epoxy , or anything else that has a Matt back (chop)such as #1708 ? Andrew , seeing that the G-3's did not have any knees in there design considering the center stringer is the only means of support for the transom , and the O.B. ............all the better to add a set of knees for a little more structural integrity to the transom area ......just my 2 cents .

OFFSHORE GINGER wrote:

Andrew , did you know that Woven roving is not compatible for use with Epoxy , or anything else that has a Matt back (chop)such as #1708 ?

Yes, I am well aware of that. This ain't my first rodeo

Actually, Woven roving can be used with epoxy, assuming it is made without binders. The cloth I'm using is just a woven cloth, again, no binders.

The Biaxial cloth that I use is STITCHED, not bonded, so it's compatible with epoxy or poly/vinylester. You can get fabric, including 1708, which IS epoxy compatible. That's what I use.

The center stringer is not the only support for the transom- There are 5 stringers that go all the way to the transom. The design is a well proven and very popular one, so I don't see ant reason to modify it from the original design. These boats have been going strong for 50+ years!

Andrew , not to stir the pot but ..............you are wrong ...when stating that fabric such as 1708 is compatible to use with Epoxy considering it was designed for Poly or Vinyl - only !!!! Hey guy ,i have worked at two Boat Co's that have used Epoxy in there build , and have had failures or should i say serious issues when ...............using 1708 with Epoxy because ......the matt (CHOP) has torn away from the fabric. Andrew , when using Epoxy you need a matless fabric like 1700 bi ax which works well . You dont want to use any chop or continous strand mats in any epoxy systems and not to be rude but no Boat Co that uses Epoxy in there build will ever touch a fabric with a chop back .....well ......the rest is history ,and some things are better left un said ....if you know what i mean... Hey guy , i am glad to hear this is not you first re-do , and is this your lively hood ?

The transom design of the G3 alone has very good strength characteristics. The transom curve is significant, which provides additional stiffness over a flat transom. As well, the floor (is tied to the stringers and hull and) butts firmly against the 15" transom about 6" up from the bottom, and when glassed in, provides solid support across the width of the tramsom and when all glassed up, completes the very stiff structure.

Andrew
Great thread, I will know what to expect when I rip into my G3.
I am looking forward to watching the whole transom rebuild through to the end.
Neil

OFFSHORE GINGER wrote:

Andrew , not to stir the pot but ..............you are wrong ...when stating that fabric such as 1708 is compatible to use with Epoxy considering it was designed for Poly or Vinyl - only !!!! Hey guy ,i have worked at two Boat Co's that have used Epoxy in there build , and have had failures or should i say serious issues when ...............using 1708 with Epoxy because ......the matt (CHOP) has torn away from the fabric. Andrew , when using Epoxy you need a matless fabric like 1700 bi ax which works well .

There are cloths, INCLUDING 1708 biaxial- that can be used with epoxy resins. Reference THIS page-

uscomposites.com/specialty.html

Note at the top it specifies that, and I quote DIRECTLY (with added emphasis),

The following biaxial fabrics are compatible for use with polyester resins, epoxy resins and vinyl ester resin.

This is one, of MANY, sources of this type of cloth.

Some Biaxial, and most matt, fabrics are not epoxy compatible because the binders used in the making of the mat that hold it together dissolve when they are soaked in poly resin, and do not do so when epoxies are used. However- There ARE plenty of biaxial cloths that can be used with Epoxy. Just make sure you have the right one!

OK folks - let cool heads prevail please. Just a suggestion - if you ever want to get in a heated disagreement with another member - think about doing a PM rather than bickering in public. Having the world read your dirty laundry will just make you more angry.

As for the transom, the curved transoms are called "pre stressed" and it is true that they are able to provide more strength than a flat transom of the same thickness. This why most large dams are curved - because of the strength. The splashwell on most of our small boats limits the addition of knee braces. I've attached an illustration of a "strong back" rib, which is another way of adding tremendous strength to any transom, flat or curved. My Reinell Jetflite was designed with one of these. It was installed under the deck, just barely below the bottom of the splashwell, and can not be seen, even when sitting in the boat.

Bruce.

Well, this 'hobbyist' hopped off the turnip truck nice and early this morning, so I got some good progress again...

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 think I might start tearing down the Lake N Sea in the meantime....

-Andrew

Nice diagram, and good description, Bruce...

There is no argument here. I stated fact, posted fact, and verification of that fact. If someone wants to make themselves look like a total idiot and continue to argue, so be it. I won't be strung along.

Perhaps they can write an E-mail to the manufacturer of the cloth to let them know that it can't be used for what they say it can be. While they are at it, perhaps they should CC that email to the thousands of people that use the cloth and let THEM know that they are all wrong, too.

Or, they could just be courteous, and not keep trying to bring threads off subject to suit whatever need they have to feel superior... Just a general netiquette tip....

-Andrew

Thanks -

Strangely enough, I'm glad that Ginger brought the subject up. I've never done a repair / restoration with epoxy or vinylester. Poly is all I know. Since the Reinell is such an important boat, I considered using epoxy or vinylester on her. I had completely overlooked the aspect of epoxy eating up the binders of chop mat. I considered epoxy because of bond strength, penetrating qualities, and lack of the horrible smell. I have read and have been told that vinylester is almost a strong as epoxy - without the expense. Since I'm so used to poly, I'll probably go with the vinylester.

So you see - there is a silver lining to this argument afterall..

Bruce

andrew thanks for the thread,i cant believe how fast you getting done,john

I may be the only one here, but I have no clue as to what you guys are talking about (other than the strength inherent in a curved transom). I used cheap resin by the gallon and mat I bought in plastic packages from NAPA to do my transom. All I can say is clean your surfaces well, and go at it!

And no, I don't want to know anymore!

Frank

Thanks, John- It's going well. I wish I'd have done a G-3 FIRST, they are really nice boats to work on, and there is a lot less to do than my Citation. Of course, I didn't know when I started the Citation exactly what I was in for- Had I known, I'd have probably passed!!

Frank- Nothing wrong with that!!

I use epoxy because I like how it works- I like the 'feel' of it, and find it far less obnoxious to work with than poly. It's a bit pricier, but in my book well worth it. I get mine from U.S. Composities, and their prices are GREAT, and I like their product as well or better than West Systems. The package isn't as fancy, but I can live with that.

Hi Andrew,

When you're done with your project, would you please write up a posting explaining the differences between the epoxy, resin, etc and the proposed uses for each. I know I would be very interested to learn more about these composites and their uses, flaws, etc.

What would be very cool would be to schedule workshops where the people in the know, like you Andrew, can spend a day sharing their knowledge with those of us not so much in the know. The EAA does this for aircraft associated subjects. I'm even all for a small fee, lets say $25 a person coveriung the materisl used to teach the class. We could have them through out the country by area. It would also be a good way to really get to know each other. Just an idea.

Bruce Gerard wrote:

OK folks - let cool heads prevail please. Just a suggestion - if you ever want to get in a heated disagreement with another member - think about doing a PM rather than bickering in public. Having the world read your dirty laundry will just make you more angry.

As for the transom, the curved transoms are called "pre stressed" and it is true that they are able to provide more strength than a flat transom of the same thickness. This why most large dams are curved - because of the strength. The splashwell on most of our small boats limits the addition of knee braces. I've attached an illustration of a "strong back" rib, which is another way of adding tremendous strength to any transom, flat or curved. My Reinell Jetflite was designed with one of these. It was installed under the deck, just barely below the bottom of the splashwell, and can not be seen, even when sitting in the boat.

Bruce. [img]http://www.fiberglassics.com/media/kunena/attachments/legacy/images /Transom_rib-20111005.JPG

bruce, the mantaray has that same crosspiece,stringer, brace, whatever you call it. looks like the dimension of a 2x4 across the whole transom, just under the splashwell. the holes is where the motor bolts on. ron

A bit more progress... 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 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. 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.

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

The G3 looks nice! Great progress there!
My old Skagit 20 had one of those pre-stressed transoms as well. Tough old buggers when repaired and glassed.

Todd wrote:

Hi Andrew,

When you're done with your project, would you please write up a posting explaining the differences between the epoxy, resin, etc and the proposed uses for each. I know I would be very interested to learn more about these composites and their uses, flaws, etc.

I started to do a writeup once, but never really finished it. You can see what I've completed so far here-

www.agott.com/glasspar/materials.html

What would be very cool would be to schedule workshops where the people in the know, like you Andrew, can spend a day sharing their knowledge with those of us not so much in the know. The EAA does this for aircraft associated subjects. I'm even all for a small fee, lets say $25 a person coveriung the materisl used to teach the class. We could have them through out the country by area. It would also be a good way to really get to know each other. Just an idea.

That sounds like fun... I've actually always wanted to go to one of the EAA workshops- Building a plane is something that I've always wanted to do!

I certainly don't consider myself to be an expert by any means, but if anyone ever wants to stop by and look over my shoulder (and help, of course!) they are more than welcome to! I've had people do that before. I've even got a guest room so you can stay a while if you need to. Be warned, though- I'll put you to work

-Andrew

Always nice to use generic words like "resin" instead of polyester, vynalester, urothane, poly watchamacallits chopped, threaded, stapled, woven, matted blah blah blah.
Resin and glass are sufficient for me, leaves a lot of wiggle room.

Learning something new with every post. Now I wonder if I should have put some short gussets (knees) on my Herters transom when I converted from the original aluminum plate to a 1 3/4" solid.

Keep up the thread, I'm curious to see how it turns out.

63 Sabre wrote:

Always nice to use generic words like "resin" instead of polyester, vynalester, urothane, poly watchamacallits chopped, threaded, stapled, woven, matted blah blah blah.

I prefer to call it that sticky crap that falls on my shoes and ruins my clothes!!!!

Hi Andrew,

I agree, the EAA workshops are really neat but very cost prohibitive. Each workshop is something like $250 a person not counting your fuel to get there, the hotel you stay in or teh materials you use. I was told by EAA officials that most of the money goes directly to the person teaching the class because they're the "expert." So much for doing it because you enjoy sharing the knowledge with others. That's a BIG difference between plane folks and boat folks, in my opinion. I appreciate how everyone shares info and tips here. Good people all around.

I like your idea about the guest room. You may want to include a packing list that includes, tools, beer, coveralls, beer, pretzels, steel toe boots, more beer...

I've been using MAS epoxy with slow hardener on the MR. It is so much more user friendly than polyester resin.

When I did the transom, all materials where cut, test fitted and ready to assemble. I preparied cups of resin for each step, minus hardener, added that when needed. Put everything together in one shot. The new framing in the boats top was all cut & fitted before any resin was mixed, I could keep going until I needed a break.

Workshops are nice. MAS epoxy has some videos out, I'm sure other mfgs have similar. Did a search on youtube for MAS epoxy, there are a few, this is a 3 part, transom replace, transom cap replace and Basics.

Yep, thats a 2x4 glassed in under the splashwell Ron. The original on mine was not attached at the ends, the new one is.

Keep the progress comin' Andrew

Thanks, Cat. Do appreciate the knowledge.

I had one stock "2X4" across the transom when I got the Power Cat. I replaced it with two double laminated 3/4" marine plywood pieces left over from building the transom. I wanted it to be better than new. Who knows?

Frank

MAS has nice videos out- West Systems also has a lot of great information on their website- Lots of research type stuff, too- Rather than just 'I know a guy' kind of tips. I, for one, Prefer data to anecdotes. They've actually got an interesting article on the use of Biax and epoxy....

The epoxy/poly question comes up a lot, and people have all kinds of opinions on the subject. I have my reasons for using what I use, and it suits me. Others like poly. Is one 'better' than the other? Depends on who you ask. There is more than one way to do something right. It's what works for YOU that counts.

There is more than one way to do something right. It's what works for YOU that counts.

So true! There are a lot of subjects I've been trying to educate myself on, and it seems this is often the case. One of the things that makes FG such a great resource is getting input on several ways of going about it, (when presented properly!) sorting through them, and trying the one you think will work for you.

Yesterday was another productive morning... I wasn't able to post this yesterday, since the thread was still locked. Let's hope that people can stay focused on the subject, and keep comments relative to what's going on here. Ask questions if you want, but any of those questions that are clearly posted just to make yourself look 'smart' will just be ignored- so don't waste the bandwidth.

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.

Today, hopefully, I'll get the sponsons sealed off, And perhaps some plywood cut. I need to get more resin before I go too much farther, though.

-Andrew

Great learning thread, keep it up till the final coat of paint.
Cal

Whadya mean, final coat of paint?!? I wanna see videos of it scootin down the lake!

That Andrew does some REAL nice work. Very cool.

Frank

Thanks, She's coming along nicely. I 'glued' the patch panels in with some thickened epoxy today, and I'll start with some glass tonight, hopefully. I've got to take advantage of this GREAT weather while it's still here!

-Andrew

Afternoon Andrew,

You do very nice work. Between you and Cal, I don't know who gets more done in a day. The speed you guys work at is amazing! Always looking forward to seeing everything you both do.

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

Hope I am not taking this thread off track as I know really nothing about what you are doing. Since I have a fetish for a G3 also, is there are guide as to the amount of strength you are adding to the transom? I am sure many restore/rebuild these boats and then add more horsepower than the boat ever dreamed of. What was the original horsepower rating of these boats and what horsepower are you looking to increase this boat to?

Andrew, in my book an iphone IS an expensive electronic.

DaveK wrote:

Hope I am not taking this thread off track as I know really nothing about what you are doing. Since I have a fetish for a G3 also, is there are guide as to the amount of strength you are adding to the transom? I am sure many restore/rebuild these boats and then add more horsepower than the boat ever dreamed of. What was the original horsepower rating of these boats and what horsepower are you looking to increase this boat to?

This boat is going to be repowered with something close to original power, likely in the 50 HP range. The old transom was plenty strong for this- And the new one will be stronger still- So there will be no worries there. I think that the original boats were rated for 75 hp

People put all sorts of power on G-3's- 100 HP is not uncommon, there are others with more. I know a lot of people reinforce their transoms to prepare them to handle the extra horses, but there are also some who dont do much back there at all, and just hang a bigger motor on there.

I've been in g-3s with 50 HP- And that was a FAST ride... I can't even imagine what 100 would do