80 Glastron gt-150 rebuild

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Hey all,

Recently started the process to rebuild my 80 GT-150. I’ve been on this boat since I was a little kid and had the opportunity to make it mine a few years ago.

Finally picked it up this past winter and decided to start putting some hours into it. Engine wise it worked great a few years ago but hasn’t been run in a while (90hp Johnson). But as you all guessed transom, floors and probably stringers are toast.

So so far I’ve gutted the interior and removed the outboard. I will be starting to split the boat this week to have access to all the rot.
 

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hvymtl939

Chief Petty Officer
Joined
Feb 6, 2017
Messages
495
Can't wait to tag along for this one! I love those old closed bow Glastrons!!
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Today I removed the rub rail around the boat. Mostly seems to want to separate except at the rear. At the back of the cap it seems poorly misaligned. And there is exposed fibreglass with no gel coat where the deck meets the transom area. I also noticed what seems like mortar between the cap and transom glass meet.

Is is this normal on these old boats or is this a repair attempt from years ago? You will also notice the cracks where the cap sits on top of the transom. There will be some repair work for sure.
 

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sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
Yep you were about to loose the o/b in the creek !
‘She looks good though ! You just gunna buff the gell out ? It looks pretty good shape ..
Welcome aboard !
 

JPO 1949

Petty Officer 3rd Class
Joined
Mar 23, 2019
Messages
96
Looking forward to your progress. Your boat looks fast just sitting there.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
The gel isn’t as good as it appears. I’ll try and get some better pictures of it tomorrow. The back end has lost a lot of the gold colour from the way the waves hit it at our dock for years. The top has what looks like layers of clear lifting, kind of white and thick looking. I will be trying to buff it out but who knows how that will end up.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
This weekend I will be building he cradle to hold the boat once it’s all apart to keep the hull from flexing. Not exactly how strong it has to be to achieve this but we will find out.

Ive been trying to plan the rebuild phase and was considering using Arauco ply laminated together for the stringers, transom, and other wooden parts. I know marine ply is #1 but not worth the cost. Parts of this boat have osb wood so I don’t think wood quality was a pressing concern during the manufacturing process at the time.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Brought the boat back from storage today. Getting ready to build the cradle and pull the cap off. In the picture below is the joint between the top cap and the transom how they came from factory or has this been cut into before?
 

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sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
My guess is it came from the factory that way . Looks like a good place for water to get in ..
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Got my cradle built today and got the cap separate off the hull. I ended up cutting the piece of glass that wraps around the top of the transom. We fought with it for 2 hours before giving in to it. It was already cracked in several places so I had to fix it anyway.

I am am going to add some more bracing to the sides of the cradle because I can already see the hull flexing and separating away from the floatation foam. I kept the frame of the cradle right on the ground to make it easier to get in and out of the boat to work with on it.
 

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78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
I removed the floor and almost all the extra wood ie ski locker foam boxes etc. Under the floor was old foam bricks that were, as suspected, saturated with water.

Do this foam under the deck need to be replaced, or can I just leave it open?

also the bilge at the back is somewhat awkward. The holes to drain into it are about an inch higher than the hull so water is constantly trapped. Also it is offset to the right so the drain in the hull is not at the lowest spot.

Can I leave a gap between the centre stringer and the transom and build a box for the bilge there? Or does that stringer need to run all the way back?

would extending the transom all the way across the back of the boat add any benefit? There would be a gap on the left and right sides due to the shape of the boat.
 

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Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
I HOPE you took a LOT of measurements before demo started. It's really important to ensure the hull is in the same dimensional shape as it was prior to decapping it. Transom is fine the way it came from factory. You can make a bilge like your planning with No Issues!!
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
I sure did take a lot of measurements. I will also be replacing one stringer at a time to ensure nothing there flexes. Also I will put the cap back on temporarily to glass in the main section of the floor as much as possible to make sure it doesn’t end up wider than it used to be.

I should be able to tab in the new floatation boxes on at the back and rear, ski locker, and the panels by your feet with the deck On to get the exact measurements as well.

Once everything is is set in place I will take the cap back off to finish glassing everything as well as replace the strips around the hull that the cap gets screwed to.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Hey everyone been a while since I posted but I’ve made some more progress on the GT. Transom is bonded to the hull now. Used 2 layers 3/4 arauco ply bonded together with pl glue as well as bonded to the hull with pl glue. The pl worked well for laminating the sheets of pl but wish I used pb for attaching it to the transom. Still on solid though

I have a few questions for the guys here.

1) the two outside stringers seem to only have been glassed with 1 heavy layer of csm. No roven at all. Will 1 layer of 1708 be enough to cover these two stringers. They are only 2” tall at the highest.

2) after removing the vertical portion of the tabbing am I okay to glass over the old horizontal part of the tabbing once ground fresh? Or should I go through the csm tabbing to the roven of the hull?

side note I wish they didn’t add about 3/4” of resin the fair the ply floor into the hull. A lot of extra grinding for something that was just covered in carpet.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
Hey everyone been a while since I posted but I’ve made some more progress on the GT. Transom is bonded to the hull now. Used 2 layers 3/4 arauco ply bonded together with pl glue as well as bonded to the hull with pl glue. The pl worked well for laminating the sheets of pl but wish I used pb for attaching it to the transom. Still on solid though

I have a few questions for the guys here.

1) the two outside stringers seem to only have been glassed with 1 heavy layer of csm. No roven at all. Will 1 layer of 1708 be enough to cover these two stringers. They are only 2” tall at the highest.

2) after removing the vertical portion of the tabbing am I okay to glass over the old horizontal part of the tabbing once ground fresh? Or should I go through the csm tabbing to the roven of the hull?

side note I wish they didn’t add about 3/4” of resin the fair the ply floor into the hull. A lot of extra grinding for something that was just covered in carpet.
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
So I noticed after installing the transom stringers and new floor there is a void between the new transom and the fibreglass hull and it’s not quite perfectly flat.

will this be a problem? It is mostly solid where the engine mounts, it’s down lower where the void is.

I’ll also need some input on replacing the lip On the cap that goes over the transom, I’ll get pics about what I’m talking about once I am able to get into the compound where my boat is stored
 

sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
Did you clamp the new wood snuggly to the outside transom skin ? You should have had enough pb in between to ooze out around the edges once it was pulled snug .. The ooze out pb will then help form the fillets around the edges of the wood for glassing .. Did you grind the skin clean and give it a good acetone cleaning before the installation ?
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
It was all ground down to the fiberglass and cleaned with acetone before applying the pb. It did ooze out all around the outside that’s why I didn’t think too much of it. I used the outboard holes with 2x4 and threaded rod to clamp it up and it seemed alright when I did it. I do realize now that I should have put a sheet of ply on the outside as well before clamping the 2x4s.
 

sphelps

Supreme Mariner
Joined
Nov 16, 2011
Messages
11,429
Pics would Be helpful . Sounds like it could have not had enough pb in some areas ..
 

78 glastron

Seaman Apprentice
Joined
Nov 23, 2018
Messages
32
I will get pics when I’m able to get my boat out of the compound it’s placed in. Hard to access right now with the situation going on as where I have to pick the key up is closed to the public right now.

I figure worst case I’ll cut the back skin open leaving 4” of old skin to reattach to, grind the pb off, rebond the outside skin then do a 2” and 4” overlap of 1708 to the hull.
 
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