bad transom

[mkpj1]

Hello,

I have a 1968 14 foot Larson All American with an original 40 Rude Lark with a soft Transom. The boat is worth, maybe 700 bucks trailer and all but it's a good runner and the family has fun with it. I have looked over seacast and total rebuild and I'm not biting. It's just not worth it. I have restored all kinds of things from cars to trucks....etc. No boats. Comes down to time and money and well time is money too. Anyway, The boat has a splashwell built into the transom and the stringers are solid. The only weak point is where the boat motor anchors into transom. I don't think this is a case of water but a case of poor design. It was bound to fail once the outer glass cracked. The transom is only an inch thick and the inner glass is the outer shell of plywood meaning I don't have enough to use seacast the easy way.
I just want to use the boat a year or two more so I don't see why......wait for it......don't pass out....I can't get a strip of marine plywood and re-enforce the weak area.....ready.....on the outside. No hate mail please! Glass it in on both sides and be done with it until I put it to pasture in a few years. The current transom is only an inch thick anyway?

Thoughts?

thanks for your reply's in advance.
Ken

 

[DJ]

Re: bad transom

What you are proposing will probably work just fine.

 

[Bondo]

Re: bad transom

I've Cheated Death,+ Destruction by doing about what you propose,.......
Only with Aluminum Plate,.... Both Inside,+ Out......

Thru-bolted,.... The Mush stood up to the Torque for Quite Awhile.................

 

[mkpj1]

Re: bad transom

I've Cheated Death,+ Destruction by doing about what you propose,.......
Only with Aluminum Plate,.... Both Inside,+ Out......

Thru-bolted,.... The Mush stood up to the Torque for Quite Awhile.................

I hear you about death and destruction. Hmmmm, Aluminum is a good idea even though I have plenty of room for 3/4 plywood. Did you epoxy behind this? Does it bond to Aluminum okay?

No real mush....yet. Started spider cracking last time out as the 30+ year old plywood...1 total inch?? failed. Mostly from being towed and tied up in the tilted up position. I've had a lot of physics but even a non-engineer can tell this is bad design. Large amount of force in a small area of the transom that happens to be the weakest point. It's not if but when. This area of the transom is small due to the splashwell being glassed in above and solid floor below. About 6 inches wide across the back of the boat. Aluminum is a good idea as I could add braces that run to the splashwell and floor to add support.

So what is the best sealer to use in combination with the alumnum, poly epoxy?? I'm a newbie with stuff

Thanks,
Ken

 

[Bob_VT]

Re: bad transom

Nothing "bonds" to aluminum. Bolts are used and they should go all the way through and be backed by yet another aluminum or stainless steel plate on the other side. Aluminum is the strongest for the weight. You cound in theory use a sheet of plywood sealed up with epoxy but bolting that through a piece of failing transom it will not be as strong.

A few photo's will help. Let us see what you are up against.

 

[samsam]

Re: bad transom

I've Cheated Death,+ Destruction by doing about what you propose,.......
Only with Aluminum Plate,.... Both Inside,+ Out......

Thru-bolted,.... The Mush stood up to the Torque for Quite Awhile.................

I hear you about death and destruction. Hmmmm, Aluminum is a good idea even though I have plenty of room for 3/4 plywood. Did you epoxy behind this? Does it bond to Aluminum okay?

No real mush....yet. Started spider cracking last time out as the 30+ year old plywood...1 total inch?? failed. Mostly from being towed and tied up in the tilted up position. I've had a lot of physics but even a non-engineer can tell this is bad design. Large amount of force in a small area of the transom that happens to be the weakest point. It's not if but when. This area of the transom is small due to the splashwell being glassed in above and solid floor below. About 6 inches wide across the back of the boat. Aluminum is a good idea as I could add braces that run to the splashwell and floor to add support.

So what is the best sealer to use in combination with the alumnum, poly epoxy?? I'm a newbie with stuff

Thanks,
Ken

My who knows how old 15' with a 40hp had aluminum plates on it when I bought it 10+ years ago, I just went and measured it. The thickness is 5/32".The outside plate is 22" wide and 15" tall with a 1 1/2" bend on the top that sits on top of the old transom. The inside piece in the splashwell is 22" wide by 5" tall and also has a 1 1/2" bend that sits on top of the other piece of aluminum on the top of the transom, so the aluminum is doubled on top of the transom and gives some fore and aft strength to everything. A few screws hold the plates generally in place. The top two motor mount bolts go through both plates while the bottom two go through the outside plate and are backed up on the inside, below the splashwell, with some 4"square "washers" made from the same aluminum. There are no braces and from what I can tell no bonding goop or caulking, although a bunch of 5200 caulking couldn't hurt when assembling. Sam

 

[mkpj1]

Re: bad transom

I agree Sam. This aluminum idea is a good one for my situation.

Here are some pics. These cracks happened on our last outing where we were in and out and I had to raise the motor repeatedly. It's about 40 miles to the lake and I didn't want to tow it with the motor down as this is a electric gear case where I would need a loan to get new parts. I braced the motor for the ride but it's just too much weight for this small area and it finally gave. Needless to say it cut our boating out.

Sorry about the poor quality of the pics. It's been raining and really humid causing my camara to fog.

Ken

 

[mkpj1]

Re: bad transom

I agree Sam. This aluminum idea is a good one for my situation.

Here are some pics. These cracks happened on our last outing where we were in and out and I had to raise the motor repeatedly. It's about 40 miles to the lake and I didn't want to tow it with the motor down as this is a electric gear case where I would need a loan to get new parts. I braced the motor for the ride but it's just too much weight for this small area and it finally gave. Needless to say it cut our boating out.

Sorry about the poor quality of the pics. It's been raining and really humid causing my camara to fog.

Ken

 

[mkpj1]

Re: bad transom

I agree Sam. This aluminum idea is a good one for my situation.

Here are some pics. These cracks happened on our last outing where we were in and out and I had to raise the motor repeatedly. It's about 40 miles to the lake and I didn't want to tow it with the motor down as this is a electric gear case where I would need a loan to get new parts. I braced the motor for the ride but it's just too much weight for this small area and it finally gave. Needless to say it cut our boating out.

Sorry about the poor quality of the pics. It's been raining and really humid causing my camara to fog.

Ken

 

[mkpj1]

Re: bad transom

I agree Sam. This aluminum idea is a good one for my situation.

Here are some pics. These cracks happened on our last outing where we were in and out and I had to raise the motor repeatedly. It's about 40 miles to the lake and I didn't want to tow it with the motor down as this is a electric gear case where I would need a loan to get new parts. I braced the motor for the ride but it's just too much weight for this small area and it finally gave. Needless to say it cut our boating out.

Sorry about the poor quality of the pics. It's been raining and really humid causing my camara to fog.

Ken

M
Hmmm, Those pictures don't open in my browser. I'm not sure what will work here. I did what the forum said to do? What am I doing wrong?

 

[Bob_VT]

Re: bad transom

You need to have your photo's "hosted" I use photobucket.com. Once the photos are loaded into a host you hit the image button, cut and paste the url and it will appear

 

[mkpj1]

Re: bad transom

Sorry about the bad form there everyone. I didn't realize it posted so many.

here is the site:

 

[mkpj1]

Re: bad transom

no here it is: Geez!

http://s95.photobucket.com/albums/l143/mkpj1/

 

[Bob_VT]

Re: bad transom

Your getting there! I will repost your photos

You will need a plate that will cover all the damage. Based on what I can see your transom is not long for this world. The plate need only be 1/4" or so but large enough to spread the force. (even a piece of diamond plate might work) On the inside of the transom you will need backing plates or a strip at least 3" wide. Use some stainless steel bolts and grease the shafts of the bolts where they pass through the transom.... and since it is a temporary fix use a sealant on the washers.

Bob

 

[mkpj1]

Re: bad transom

How did you do that Bob? I did what it told me. I don't have to write html script to post them do I? Yikes. Well I really appreciate your assistance and advice.

There is no doubt the Transom is shot and from my investigating there IS a small amount of rot near the bolts that go through the transom. The glass finally gave and started to sag. The diameter of this problem is mostly local to this point though extending out maybe 6 inches and then it is very solid.

I have one piece of aluminum that is 18" x 12" for the outside and 6" x 12" peice for the inside. These plates will extend me into solid Transom and as you say spread the force out again. The splash well is large and tied in adding strength.

My idea was to first re-glass over the cracked areas in the glass front and back. Then secure the aluminum on both sides with bolts all the way through just as you have suggested.
Then...... I am entertaining glassing over the edges of the aluminum extending to the edges of the boat for added strength and blending it in.
Is this a good idea or a waste of time? I have never worked with glass before?

Ken

 

[Bob_VT]

Re: bad transom

It would be a wast to attemp to blend and glass the aluminum. The fiberglass will not adhere and only crack. You could use a bead of 3m 5200 around the edges but not needed. You could drill a small 1/8 or 1/4 inch hole (only through the fiberglass) at the end of the crack to prenet it from traveling and just use 3m 5200 to fill it and seal the crack. If the 18" is wide enough go for it. Use good bolts and large washers. 4 bolts in the corners should do it fine. The only other advice would be to place a small plate under the screw downs where the engine top mounts are. Most people use 2 additional bolts that pass through the plates and the engine mount.

As far as getting photos to appear:
In photobucket you will see that under the photo the URL is listed....... copy the URL now in this reply box on the top there is a small box and what looks like mountains in it..... click on it (it's the img box) and a small window will appear. Erase (or backspace the www.... in that window and paste in the URL you copied. That is all there is to it.