Peeled the Delta..

Dougw · **Posted:** July 25th, 2019, 7:16 am

mattmak wrote:

Any opinions on using Coosa? It won't save more than 15lbs.. Coosa costs a lot, and I already have a full sheet of marine ply at home.

I used an even lighter foam in my Thundercraft transom and stringers. Resulted in a lighter boat but moved the CoG forward which didn't help top speed. It is holding up well and I like the peace of mind of no water absorption or rot. But who knows how long it hold up in terms of vibrations, crushed by the engine bolts.. It has been only 4 years so far.

I've noticed recent Critches have Coosa transoms...

I have always used wood for all of our builds and wouldn't worry about 15lbs unless I was drag racing at Jasper. I figure if the Master - Wally Lamkin still uses wood in all his Triads than that is good enough for me.

DoktorC · **Posted:** July 25th, 2019, 9:34 pm

Dougw wrote:

mattmak wrote:

Any opinions on using Coosa? It won't save more than 15lbs.. Coosa costs a lot, and I already have a full sheet of marine ply at home.

I used an even lighter foam in my Thundercraft transom and stringers. Resulted in a lighter boat but moved the CoG forward which didn't help top speed. It is holding up well and I like the peace of mind of no water absorption or rot. But who knows how long it hold up in terms of vibrations, crushed by the engine bolts.. It has been only 4 years so far.

I've noticed recent Critches have Coosa transoms...

I have always used wood for all of our builds and wouldn't worry about 15lbs unless I was drag racing at Jasper. I figure if the Master - Wally Lamkin still uses wood in all his Triads than that is good enough for me.

I'm with Doug...I love wood and balsa core. It's way less itchy than coosa...

mattmak · **Joined:** June 5th, 2015, 8:56 am **Posts:** 516

Itchyness has already started.
I've decided to not buy Coosa, but to use what I already have which will be mostly marine ply for the transom. Might still do something interesting by adding some less dense foam core too.

I've got the core out from the sides, and started on the core in the pad. It is slow going. And it is mostly wet. So a lot of weight coming out of this boat. I'm thinking I'll have to figure out a way to save weight in the deck too or else the CoG will be moved too forward..

I had weighed some of the wet wood from the transom and then let it dry out in a bin for a couple days, weighed it again: 13lbs of wet wood became 10lbs of dry wood.

mattmak · **Joined:** June 5th, 2015, 8:56 am **Posts:** 516

hec2buck · **Joined:** August 22nd, 2013, 4:13 pm **Posts:** 273

Yuck!!! Your doing a nice job Matt.

mattmak · **Joined:** June 5th, 2015, 8:56 am **Posts:** 516

Thanks, but the "nice" stuff hasn't started yet. Still just cutting, prying, grinding. Spent some time over the past couple days getting a T750 boat ready!

Update on this Delta:
- Did some building of a straight and square cradle in between the hull and trailer. Picked up a long bubble level to add to the arsenal of tools. Took the use of two bubble levels, a couple 5 foot aluminum extrusion as straight bunks, and a digital angle gauge, and various thickness scrap materials for shims. It will work out well.
- Almost all the core is out. Amazingly there is rotten core all the way up to the tow eye. Will probably have to grind out the whole tow eye support, if it is rotten too.
- I did start some grinding and will hopefully start mocking up the transom an knees (today maybe?)
- With coffee and contemplation this morning, I looked through tunnelv's Delta rebuild thread again, and Zonka's.. Dreaming of when mine will be all shiny and nice.. ..and straight and dry and lighter weight..

mattmak · **Joined:** June 5th, 2015, 8:56 am **Posts:** 516

Looks like this boat has lived many lives.

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Peeled the Delta..

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