DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wrong)

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

i just passed by a shop looking for 1708 and he told me for the size of my boat 1708 is overkill. once i glue the transom to the hull i should use 2 layers of 1.5 csm to skin the transom. is he wrong?
 

Woodonglass

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Hmm...Look how good the OTHER shop did!!!! No one here on iBoats would ever tell you that.

I'd stick with the 1708. CSM really has no structural strength. It helps bond the resin and keeps it from breaking like glass. The weave of the 1708 on the other hand DOES have structural strength and you should absolutely use it to tab the transom to the hull at the very least. You do not have to cover the entire transom with it but a 8" to 10" tabbing is necessasary IMHO if you want your transom to be strongly tied to your hull.
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Hmm...Look how good the OTHER shop did!!!! No one here on iBoats would ever tell you that.

I'd stick with the 1708. CSM really has no structural strength. It helps bond the resin and keeps it from breaking like glass. The weave of the 1708 on the other hand DOES have structural strength and you should absolutely use it to tab the transom to the hull at the very least. You do not have to cover the entire transom with it but a 8" to 10" tabbing is necessasary IMHO if you want your transom to be strongly tied to your hull.

thanks. i tell you everyone has an opinion but i really like the ones i receive here. i will add the 1708.
something else i spoke with us composite the other day and the person who helped me told me to not cap the stringers. just add glue(EPOXY) on the top so do the floor can adhere to it.
 

Woodonglass

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

You could do that, but there is no need to. You seem to be falling into the "Paralysis by Analysis" syndrome. I would advise you to not overthink everything. Make a decision on how you want to do things based on your own research and beliefs and then do it that way. Don't doubt yourself or the advise that makes sense to you. Everyone has an opinion but, in the end, it's only yours that matters, cuz it's your boat and you're doing the work. The advice you get on here by those who have been there and done that and you can SEE by the pics and the results is usually a good measure of how you should proceed. Having said all that, I stick by my initial advice and drawings on how to fabricate stringers.
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

You could do that, but there is no need to. You seem to be falling into the "Paralysis by Analysis" syndrome. I would advise you to not overthink everything. Make a decision on how you want to do things based on your own research and beliefs and then do it that way. Don't doubt yourself or the advise that makes sense to you. Everyone has an opinion but, in the end, it's only yours that matters, cuz it's your boat and you're doing the work. The advice you get on here by those who have been there and done that and you can SEE by the pics and the results is usually a good measure of how you should proceed. Having said all that, I stick by my initial advice and drawings on how to fabricate stringers.

thank you very much!!
i was wondering how do tab the top of the transom? do i tab it to the hull skin?
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

what are the chances that my hull has warped?
 

Woodonglass

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Warped????
 

JDA1975

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Moving right along man...your going to do a much better job than that hack job they did! I never did notice what kind of support system you given your hull, is it just sitting on the trailer alone? Or did you build a cradle? Noticed during transom removal video at one point you set the transom down in the hull and it shook all the way at the camera, May want to ensure your hull is sufficiently supported so it does not warp during tabbing. Tear down I did not support mine, it was not until I had my bottom work done and flipped that I placed it in a cradle and I can walk around inside without any of moving or warping. It may have been a mistake but I think I built my cradle properly and do not have a warp in it now...
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Moving right along man...your going to do a much better job than that hack job they did! I never did notice what kind of support system you given your hull, is it just sitting on the trailer alone? Or did you build a cradle? Noticed during transom removal video at one point you set the transom down in the hull and it shook all the way at the camera, May want to ensure your hull is sufficiently supported so it does not warp during tabbing. Tear down I did not support mine, it was not until I had my bottom work done and flipped that I placed it in a cradle and I can walk around inside without any of moving or warping. It may have been a mistake but I think I built my cradle properly and do not have a warp in it now...
just on the trailer. im not planning to take it off. i was looking at the sides of the inner hull. it has two long rectangular pieces of wood but incased with fiberglass. i think their called gunwales but i could be wrong. its so strong that i think it wont allow the hull to warp but not really sure.
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Warped????

yes. since the cap, transom and soon stringers(will r&r one at a time) ive read that my hull can warp and i will have problems with fitting the cap.
 

Woodonglass

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

This is true. You should take a lot of measurements for the width of the deck while it is still in the boat and then when you put in the new one make sure the measurements stay the same. You can use nylon straps to help hole the hulls shape as well as making a cradle to support the bottom of the hull.
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

This is true. You should take a lot of measurements for the width of the deck while it is still in the boat and then when you put in the new one make sure the measurements stay the same. You can use nylon straps to help hole the hulls shape as well as making a cradle to support the bottom of the hull.
i dont understand. why would i make a cradle if the trailer does the exact same thing? or am i wrong? does it matter if its a trihull instead of a vhull?
 

GT1000000

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Howdy jarrpal001,

Just jumping on board to give my 1/2 cents worth...

The trailer does a fine job of supporting the boat when it is one complete structure.

When you are doing a complete restoration, even if you remove one stringer at a time, that part of the hull becomes weak and prone to flexing or warping...while it may or may not amount to much, you are taking a chance of the hull deforming just enough, that when you go to put it back together, it may not fit or actually become deformed...

If you are doing the "standard" complete restoration which usually involves removing the cap, etc..., and you are replacing the stringers and transom, you should support the hull by building some form of cradle to keep everything properly aligned, so when you go to install the cap back on, you don't find that it won't fit...

The actual hull of the boat is usually a very thin, around 1/8 of an inch thick, lamination of fiberglass. This is then made structurally "solid" by the stringers, transom, bulkheads[ if designed into the hull] and the cap. When any or all of these are removed in the process of a restoration, stresses will be applied to the weak areas of the hull and these could adversely affect the shape. If it is not properly supported when being reconstructed, it could change the shape of the hull enough that it won't go back together the right way. If your trailer support happens to be under one of the stringers that you removed, the hull may actually "give" upwards, and when you go to replace that particular stringer, it may not sit at the correct original height and cause you problems later on...that is just one example that immediately comes to mind...

A proper cradle for the hull can be thrown together in a matter of hours and for very minimum of cash outlay, compared to the amount of time and money that you are going to be putting into a complete restore, and provide the security and peace of mind knowing that your hull will maintain its shape throughout the entire rebuild. Since you really only have to do this once, there is no reason to skimp on this part of the process. It would be a shame to put all of the effort and money into a restoration, only to find that you have to go back and tear out what you've already done, and start over...

Also, by building a cradle, it wont be absolutely necessary for you to replace "one at a time" the stringers, etc...instead you can do all of your initial grinding and prep work in one complete shot, then begin the reconstruction process...which is generally more a efficient use of time ...

Again, just my 1/2 Cents worth, for what its worth...

Best regards,
GT1M
 

JDA1975

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Cradles are nice, but not necessary, if your limited on space, you can leave it on the trailer, use the existing bunks to support part of it and build more support on top of trailer frame to support the other spaces. I would recommend at least 1 bunk or support for each part of the hull that changes height, and use a strap to keep the sides at the correct measurements. Basically you want to be able to walk around and not feel any movement or give...the video where you set the transom wood down and shook camera just caught my eye, because if you did that on mine it wouldnt shake at all as it is supported fully
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

thanks guys now i need tofigure out how to get it done.
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

ok guys its been a long time that i have been away from iboats. last we left off we were talking about possibly having an issue with the hull being deformed. well i think its deformed. the cap is not fitting correctly on the hull. not sure if have to play with it some more or its deformed. i should have learned more about making a cradle or supporting it before i ever starting working on the boat but i cant go back to the past. is this boat a junk piece now? since january all ive done is installed and tabbed the transom.
 

jigngrub

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

It doesn't have to be junk if you don't want it to be... but you will have to take it back apart until the cap fits again and then put it on a cradle to hold the proper shape, then start putting it back together and pay close attention to your dimensions.
 

GT1000000

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

Take some pics of the trouble spots...you might be able to persuade it back into shape using ratchet straps...
 

jarrpal001

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Re: DIY-1972 thunderbird shawnee tri-hull boat restoration-(after shop repair gone wr

ill upload a video later.20121028_142358_resized.jpg20121028_142403_resized.jpg20121028_142413_resized.jpg20121028_142447_resized.jpg
 
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