New transom keyhole area not as flat as I thought

[Jimmy H.]

Apparently I love learning things the hard way...
Anyways I am a ways from mounting everything back on but today I removed some rusted studs from the gimble and thought why not hold it up to the transom to see how it looks.
What are my options for the outer transom not being within 1/16" of flatness? Vertical it has a 3/16" gap in the middle. The inner transom I knew wasn't perfect but figured I could grind and lay glass to flatten it. Not really sure what to do with the outer.
Thanks in advance.
James

Horizontal looks good

Vertical not so good

 

[xanthras]

Re: New transom keyhole area not as flat as I thought

Not sure exactly on that one but i am really curious to what the experts will say. Good luck!

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

I have been searching, reading, asking, etc... I can see three options...
1 - remove new transom and redo to try and make area flat. -
2 - sand gel goat and apply more to build up low area.
3 - remove gel coat off rear down to glass and apply more glass to flatten and re-gel coat.

I'm ok with options 2 and 3 as the rear gel coat needs attention anyways. not sure what to do...
I would like to hear from someone with experience that's been through something similar.
Thanks again!

 

[Marada92]

Re: New transom keyhole area not as flat as I thought

What is your overall thickness of the transom? If your already pushing the limits on thickness then building up the outer skin may not even be an option either. Hopefully someone will help you out here... I've tore out a brand new transom.. It's no fun trust me!

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

It's right at 2" now. The transom is not glassed in yet, only tabbed in around the edges. I have the opposite effect on the inner side where the middle secton is a bit high. So my thinking is if I build up the outer middle section I need to take down roughly the same amount on the inner and end up right back at 2". Once it's flat, glass the inside and end up with a thickness around 2 1/8"-2 1/4"
Thoughts?

 

[Bondo]

Re: New transom keyhole area not as flat as I thought

It's right at 2" now. The transom is not glassed in yet, only tabbed in around the edges. I have the opposite effect on the inner side where the middle secton is a bit high. So my thinking is if I build up the outer middle section I need to take down roughly the same amount on the inner and end up right back at 2". Once it's flat, glass the inside and end up with a thickness around 2 1/8"-2 1/4"
Thoughts?

Ayuh,.... Clamp it together, 'n see if it Flattens...

It's Gotta be Dead flat, 'n True, everywhere the transom assembly mounts, or you'll be bustin' stuff...

 

[xanthras]

Re: New transom keyhole area not as flat as I thought

From my limited knowledge I like number 3. If your transom is then too thick after that, seems to me you could just sand off the inside a bit to get it back to 2 inches. Number 2 may work but Gelcoat that thick seems to me that it would be brittle. Not something you want where your engine is putting stress. Maybe someone else will chime in

Clamping sounds like a crap shoot to me. Wonder how much it would flex be for cracking.

 

[Marada92]

Re: New transom keyhole area not as flat as I thought

Was the the new transom wood warped when you glued it in the hull? Seems like it may have been so that when you installed it the outer edges of the wood were touching and once you clamped it in the pressure forced the outer skin to flex and take the shape of the wood. What did you glue the wood to the outer skin with?

 

[Decker83]

Re: New transom keyhole area not as flat as I thought

Hey Jimmy H I am no expert by no means. If you have not glassed in the inside of the transom, I would find some heavy angle iron and drill some holes in the transom and angle iron and pull the transom flat. You may be able to use the holes that or already there. Once you have the transom pulled flat then glass the inside of the transom with a layer of csm and your 1708. This may slove the problem with the warped plywood. Just a thought.

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

Thanks, Great help and ideas coming in. I aggree I dont want to thick of gel coat on the back. Clamping to see if it flattens spells disaster as I'm sure I'll crack the gimble.
The transom was 4 layers of 3/8" and one layer of 1/4, The wood was not warped. I must have been the way I positioned the 2x4's to clamp it down with. I had four on each side and since the hull is curved it sucked it in the middle as I tightened... (photos below)
I used pl construction adhesive against the hull and between the layers.
Decker - Perhaps a bullseye! well at least worth a shot, I'm going to give that a try... worst that can happen is not too much and with a bit of luck I can get it in enough that a thin layer of gel coat can do the trick. I'll clamp it asap and glass the inside soon plus (not sure if it matters) I can leave it clamped for a few months even and perhaps it may take the shape better??

only one layer on this pic so far, i used the same order when the next three layers went on

this is how it is right now

I'll rig up some clamping device and try to pull it out a bit further than it needs and hopefully after glassing and sitting clamped when I release it might end up straight?
Now looking and seeing the stringers attached to the transom I'm wondering if I can flex it out at all... :facepalm:

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

Perhaps I will just cut the stringers away where they meet the hull. I would have a better shot at pulling the hull out a bit. Peanut butter it back together while its pulled away and may help keep it in the new position.

 

[Decker83]

Re: New transom keyhole area not as flat as I thought

Cutting the stringers lose is a good ideal. If you take your time and get it all clamped out flat, it should work. Best of luck.

 

[mrdjflores]

Re: New transom keyhole area not as flat as I thought

one cause might be your clamps....when clamping the wood transom to the outer hull...turn the 2x4's on end...clamping them flat can just let them bow....they are much stronger on end..

like Frisco did here:

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

For sure was the clamping. oh well, next time will be different. Think that's #34 on my list of things not to do next time!!
I'll be outside after work trying to flatten things out. I'll post the results.
Thanks everyone !!!

 

[Woodonglass]

Re: New transom keyhole area not as flat as I thought

Sooo... You used PL adhesive to glue the transom wood to the outer fiberglass skin of the boat???

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

Yes, I also used it to bed the stringers in.

 

[Bondo]

Re: New transom keyhole area not as flat as I thought

For sure was the clamping. oh well, next time will be different. Think that's #34 on my list of things not to do next time!!
I'll be outside after work trying to flatten things out. I'll post the results.
Thanks everyone !!!

Ayuh,.... Only #34,..?? Fill it, 'n fair it out,.... It's lookin' Good,....

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

UPDATE BELOW WITH PICTURES

Quick note... Didn't go so well tonight.
Photobucket web site is down for some reason? no pics yet sorry.

1st attempt was weak, didn't even budge. (four wimpy wood clamps)

2nd attempt was better and actually moved the gap to 2/16" until the wooden brace snapped. (winch with steel cable)

3rd attempt will have to be another night and I'll give it everything I got. (Steel, huge threaded rods, etc...)

I'll post pics of all when complete and hope for a happy ending. Final round, something is going to give.

 

[Trooper82]

Re: New transom keyhole area not as flat as I thought

I'm watching to see how this goes....thinking I may have to do some flattening of mine...

Photobucket was down for me too, but back up now...

 

[Jimmy H.]

Re: New transom keyhole area not as flat as I thought

ok thanks, I'm on it. give me five minutes for pics.

Sorry tried but photo bucket shows errors when trying to upload pics. I tried a old pic to test and did the same thing so no pics tonight I guess