'73 Larson tri hull rebuild/restoration thread

97fordrunner

Seaman
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Jul 10, 2014
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71
Hi all, I finally started tearing down my boat to replace the stringers and rotten transom, ive been taking pictures and video (cell phone😒) and if anyone has helpful suggestions and constructive criticism by all means please share.

First picture is the engine on my stand along with the outdrive


Engine compartment after engine was removed



Last picture for now if the rub rail on the front corner, I'm hoping that's not oem but it also makes me nervous what else I'm going to find
 

97fordrunner

Seaman
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Jul 10, 2014
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First video is just a quick overview and problem with how it seems the bow has a deeper portion of the hull that is retaining water when it's on the trailer
 

97fordrunner

Seaman
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Jul 10, 2014
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This is the latest from today, I think I decided on not flipping the hull for repairs, I think I should be able to do the very minor gel coat repairs and then paint the hull on the trailer, I know it's not ideal but the portion that the rollers support are the inner V so taping of the roller contact area and doing everything else, letting it cure and then rolling the hull back 6" to access the in painted roller spots would allow me to tape the newly painted spot to only paint the old spot and then just blend it, but again this would be on the inner Voice so it's not going to be really visible. Let me know your thoughts
 

sphelps

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Nov 16, 2011
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If you flip , which will make it a lot easier to paint the hull , I would do your demo first .. Probably a lot of extra weight with wet foam and wood .. I would also go ahead and do the repairs ...At least the transom and stringers before the flip ... But that's just me ... Others may think differently ..
 

97fordrunner

Seaman
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Jul 10, 2014
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If you flip , which will make it a lot easier to paint the hull , I would do your demo first .. Probably a lot of extra weight with wet foam and wood .. I would also go ahead and do the repairs ...At least the transom and stringers before the flip ... But that's just me ... Others may think differently ..

Would the cap need to be back on to keep the hull in shape or would that not be an issue?
 

sphelps

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For the flip no ... You can install some temporary bracing across the hull to help keep it more ridged for the flip ..
 

Slager

Petty Officer 2nd Class
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Apr 30, 2014
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I'll follow along if you don't mind.

If your going to flip, having a transom still in or replaced may be an advantage, because of the tow eyes. You can use them to lift one side of the boat.
 

97fordrunner

Seaman
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Jul 10, 2014
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Quick question guys, ive been brainstorming ways to support the sides of the hull once the cap is removed, is this something that I even need to worry about? I've only found one YouTube build so far on another tri hull that he did it but I just don't see it being necessary since the main hulls should all remain supported by the trailer rollers, but I don't wanna find out after the fact I was wrong, thanks guys
 

sphelps

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As long as you have it well supported under the hull it should be fine ...On a bunk trailer you can add a few extra temp bunks to help shore it up .. You may want to take some measurements across the sides before the cap comes off and record them for later when you glass the new deck in .. About every 2 ft or so down the length of the boat ... Mark the sides where you take the measurements...
 

97fordrunner

Seaman
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Jul 10, 2014
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Copy that, I will do that for sure, gonna figure out a way to attach a coyote 2x4s side to side against the trailer frame then put a bunk on either side and use some of those carpentry shims to keep it even around the curve of the hull. Also watched all of Frisco boaters videos on his sea ray build and glastron and am on his Carlson , ton of great info.

My most recent videos from tonight, just sticking the camera where I can't get my fat head to see what I can see
 

97fordrunner

Seaman
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Jul 10, 2014
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Here is a video from stocking the camera in from the rear under the floor, lots of stuff that doesn't look friendly.
 

97fordrunner

Seaman
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Jul 10, 2014
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So I got to work a little on the boat this morning and got one side apart, the top part is 3/4" Maine grade still solid with carpet, then under that is 1/2" plywood that was partially fiberglass then it looks like 1/2" dimensional timber under that over the foam!!! Why would anyone do that? The dimensional and 1/2" ply looks like the original, I just don't know why anyone would do that.
 

Woodonglass

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No tellin' what you're gunna find with a 43 year old boat. Obviously the deck has been replaced and it could have been done multiple times. Fast easy method is to do and "Overlay" and to heck with the ROT going on underneath.:eek:
 

gm280

Supreme Mariner
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Jun 26, 2011
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Does look like everything has to come out. Just think of all the extra weight those multiple floors are causing. Especially being rotted and water soaked. So I think you are going to strip the entire hull and start over with fresh materials. But so many others are doing the exact same thing that you are in good company and also on the best forum to get help, assistance, suggestions and ideas. Lots of great folks on here to guide you along. Keep posting the pictures and videos.
 

sphelps

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The dimensional lumber kinda looks like was some backing placed in at stringer level to support a seat or something on top of the deck .... That is unless it's under the whole floor ... Which would be kinda strange ... :twitch:
 

97fordrunner

Seaman
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Jul 10, 2014
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So the confusion continues, again in getting way ahead of myself but I wanted to see if there was anything left of the stringers , well there are no stringers, just woven roven glass and foam.......
 

sphelps

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Some manufactures used foam in the stringers ... I have never had one with foam ... But if it is soaking wet ya may want to replace it ... I would cut the top of the stringers off in enough places to dig the wet foam out ... Repair any bad glass or places where water can get back in and re pour the stringers ...
Others may have a different plan .....
 
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