Transom replacement - - Slight " barrelback"

[pro-crastinator]

Yeah, I know - a tired old subject line -
But this question has a slightly different slant. (pun intended)

Starcraft Marlin. 1965. - The transom has a SLIGHT "barrelback" design

It looks like the original transom was put in BEFORE the three "knee braces" were riveted in.
(yes, it has three knee brace brackets from the floor to the transom.) (pic1)
Cutting the transom so it can just slide down will leave a small void on either side. (pic 2)
Has anybody discovered some ingenious solution that doesnt involve drilling out perfectly good rivets?
I am leaning towards just having the voids on either side. I can deal with the bolt hole that will no longer serve a purpose. (pic3)

The present transom is pressure treated ply that is not gonna be there for long.

Thanks for looking.
-Bennett

 

[GA_Boater]

What rivets need to be removed? None that I see. You only have the bolts through the two outside braces and the two singles on either end. Plus the ones in the center and for the corner caps..

I hope you aren't talking about removing the knee braces - they stay in place, Pro.

 

[jbcurt00]

To get the transom to not have the reverse cut at the ends w that void shown in pix 1, you'd have to take the knee braces out. Which means removing the thru the hull bottom rivets. Yep, only way to do it and go full width.

My Duracraft has even more barrelback shape and I took the knee brace out. BUT it was only 1 knee brace.

IMO, replace the transom w the same shape and void as whats shown in pix 1.

I probably wouldn't have taken my knee brace out if I could have gotten the plywood back in, even if needed to be trimmed a bit. I couldnt because the transom skin rolls up and over the plywood. Theres no upside down C channel trim over the plywood. Its all the exterior transom skin.

 

[GA_Boater]

I hope you aren't talking about removing the knee braces - they CAN stay in place, Pro.

Dropped CAN in the first reply.

 

[Watermann]

My SeaNymph had a very similar wider down lower shape to the transom too. Although the bottom of the entire transom is cradled in a very stout piece of AL with a single center knee brace that only attached to the cradle.

You have 2 choices, either remove the knee braces or cut the transom so you can return it without using a hammer. My opinion, that small bit of transom wood missing won't matter for strength. If you're worried about how it looks you can think of a way to cover it or at least make it more rounded and even..

 

[hayko1971]

i wouldn't remove the knee braces either. Were it me, I'd remove the top corner pieces and cut it the same, it looks like it would wiggle in there. Then with scraps cut off from the shape, I'd cut triangular wedges to glue and wedge into the empty corner spaces. It might not provide anything structurally, but it would satisfy me lol.

 

[g0nef1sshn]

Maybe if you just took the corners off to get it out, it can drop in far enough on one side to let the other side drop in. Then level it and pull it up in place? Hard to tell from the pics.

 

[64osby]

A others have said corners off cap off.

If the new wood can't be wide enough to have a bolt catch the wood in that empty hole, fill the hole and install a new bolt an inch or two toward the center.

 

[pro-crastinator]

Thanks for the thoughts.
I have NO DESIRE to take out the knee braces. It aint broke and I aint fixin it.
Taking into account all your ideas and comments, I am "leaning" now towards the following:
New transom wood will be cut to allow spaces on the right and left side.
I am thinking about a piece of angle aluminum that will bolt thru transom skin holes and be fastened to transom wood.
That idea is the mechanical part. I really need it to look good. Ugly is not where I want to be.
I'm not screwing up the looks of this cool old boat.

About 64osby's idea of a new bolt hole. It has merit but when I look at the three beefy knee braces staring at me, I have to wonder if it is necessary.
I think I can get away without em - with plenty of margin - and the alum angle idea will give some added support.
The outboard that will grace the back of this beauty is a weighty one. I got a good deal on a 175lb, 25hp, 2015 yamaha f25. picked it up last week.
rated for a 40hp circa 1965, I think I'm in the weight range I need to be. time will tell.

 

[64osby]

My idea on the lower hole is to keep the wood from twisting under stress.

It could also be accomplished with a wrap around on the corners that attaches to the hull transom skin and to the wood, or an angle attached to the hull side and the wood.

This is what my Lone Star Big Fisherman had on the sides of the transom.

 

[pro-crastinator]

I think you got a good idea.

 

[Watermann]

Pretty much all the later models of SCs have the side brackets that attach the side of the hull to the transom. Although they weren't over built with 3 knee braces but the angle AL on the ends of the transom would hide the gap needed to install the new transom wood.

 

[pro-crastinator]

No Title

Here we go.
8 pics that get "us" up to date.
Look for commentary on the captions. (fingers crossed)

 

[64osby]

Looking Pro pro. :encouragement:

3M 5200 or 4200 for sealing the transom bolts. Also make sure the motor pad bolts get sealed also. I have used Marine Goop on bolts on a few of my small tinners.

Angle on the transom corner looks like it should do the trick.

Several layers of JB Weld might enable you to remake the star in the transom cap. Another more expensive option would include having a scrap piece tig welding in place.

What did you seal the pine with?

 

[GA_Boater]

Ditto on the 4200 or 5200 from 3M. The leftover makes good toothpaste or deodorant.

Transom should be good to go. A OP butchered the corner cap.. A plate tigged in to help fill the hole before trying the JB to remake the star might be a good idea. That's a big hole for JB only to fill.

What motor is going on the back, Pro?

 

[Watermann]

Looking good and some good suggestions.

I don't know about welding cast AL and sheet AL together, not sure it would work out so well. I think I would use some of that left over 5200 to adhere a piece of AL on the under side, clamp it for several days and then fill with JB or MT and remake the star. Thing is you would need to paint the end caps after that to make things look right.

 

[pro-crastinator]

Ga Boater - I got a deal on a 2015 Yamaha F25 that weighs in at 175#. I figure that the circa 1965 - 40 hp rating assigned to the Starcraft Marlin puts me in the right weight range. I picked it up a couple of weeks ago. One of my goals for this boat is to put it in the upper Savannah river - just below the dam at Augusta Ga - and motor down to Savannah and Tybee Island. Thats under 200 miles and an absolutely solid and dependable motor is a must. - But we are a little ways from that grand plan.
Waterman - The corner caps - I think I am going to fill them with the same epoxy resin that has been used on all the seats and transom and dash board. Once I get the hole filled I can get picky about recreating the star pattern.
Today, I am picking up the 5200 and seal up the bolts on the transom.
Also still need to improve the fit of one piece of flotation - the 1" conduit messed up my spacing a small bit for 1 flotation foam board panel.

Interesting note - Yesterday, my task was to cut pieces away from the trailer because the boats "new" beam of 64" didnt fit on the trailer and it was making contact on both sides with the side bunks. Seems that it has not seen its stock width for many years.

 

[pro-crastinator]

Ho-lee crap! That 5200 stuff is the awfullest (new word) stuff, and it has some wierd ability to get on everything within a 5 foot circle of the tube.
I have high hopes it will keep out the wet stuff. Tube is in the frig.

 

[GA_Boater]

The leftover makes good toothpaste or deodorant.

Don't forget that! ^^^^^^

It is the vilest, messiest stuff on the planet and takes 7 days to cure. One way to speed up or shorten curing time is to mist it with water. Only 6 1/2 days then. LOL

I heard freezing does extend the usable time of an opened tube.

 

[g0nef1sshn]

One of my goals for this boat is to put it in the upper Savannah river - just below the dam at Augusta Ga - and motor down to Savannah and Tybee Island. Thats under 200 miles and an absolutely solid and dependable motor is a must. - But we are a little ways from that grand plan.

That sounds like an awesome ride to do. I just watched a 4 part video of a guy that went from Michigan to Florida a few days ago. To me thats better than any cruise you can take.