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Author Topic: Foam stringers or coosa ?  (Read 140 times)

March 25, 2024, 06:40:45 PM
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Blueline93

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Foam stringers or coosa ?
« on: March 25, 2024, 06:40:45 PM »
The time has come for me to start putting stringers back in, except now I don’t know what to do.the old stringers non existent and had to be completely removed. So do I build a form and pour foam stringers and similar to the trapezoid style originally in the boats or do I splurge and make them out of coosa ?

March 26, 2024, 02:34:42 PM
Reply #1

RickK

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Re: Foam stringers or coosa ?
« Reply #1 on: March 26, 2024, 02:34:42 PM »
You could do either. I built my trapezoid stringers from scratch with 1708. If the stringers were not in the boat when you bought it you don't have any measurements from the cap down to the top of the stringers, to go by. Have you replaced the transom already or do you still have the evidence of where the stringers attached?
Rick
1971 "170" with 115 Johnson (It's usable but not 100% finished)

1992 230 Explorer with 250 Yamaha

March 26, 2024, 08:58:04 PM
Reply #2

Blueline93

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Re: Foam stringers or coosa ?
« Reply #2 on: March 26, 2024, 08:58:04 PM »
I pulled measurements and laid it out before I cut the old stringers out so I could replicate just not really sure how to make the form. I would rather go back with the trapezoid stringers as that’s what the boat was engineered with and I know they’re pretty strong. Any info on how you made the forms ?

March 27, 2024, 08:43:59 AM
Reply #3

RickK

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Re: Foam stringers or coosa ?
« Reply #3 on: March 27, 2024, 08:43:59 AM »
I pulled measurements and laid it out before I cut the old stringers out so I could replicate just not really sure how to make the form. I would rather go back with the trapezoid stringers as that’s what the boat was engineered with and I know they’re pretty strong. Any info on how you made the forms ?
Glad you did that. Did you get measurements to the top and bottom of the stringers? That would tell you how tall they were and how tall to make the forms.
Here is where I started https://classicaquasport.com/smf/index.php?topic=10101.msg89831#msg89831

I started by using 1708 for each and then joined them together, If I had to do it over I think I would make a 16ft long mold so I didn't have to join them.

Joining them https://classicaquasport.com/smf/index.php?topic=10101.msg90053#msg90053

Layout/planning https://classicaquasport.com/smf/index.php?topic=10101.msg90478#msg90478

Update on joining the stringers https://classicaquasport.com/smf/index.php?topic=10101.msg91891#msg91891

Scribing the stringers https://classicaquasport.com/smf/index.php?topic=10101.msg93388#msg93388

Anchoring the stringer https://classicaquasport.com/smf/index.php?topic=10101.msg95291#msg95291
Rick
1971 "170" with 115 Johnson (It's usable but not 100% finished)

1992 230 Explorer with 250 Yamaha

March 27, 2024, 08:50:55 AM
Reply #4

Ulysses485

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Re: Foam stringers or coosa ?
« Reply #4 on: March 27, 2024, 08:50:55 AM »
Personally I would stick with Trapezoidal Stringers. The boat was designed that way and believe that if the stringers were narrow, the hull bottom would need to be thicker to prevent cracking considering the pressures across the span between stringers. Im no engineer but have a few ongoing similar projects and put this to thought on my 222 Flatback at times. Hope that helps.
1974' 240 CC - https://classicaquasport.com/smf/index.php?topic=15975.0
1970’ Flatback 222 - https://classicaquasport.com/smf/index.php?topic=15666.0
1981’ Osprey 22-2 - https://classicaquasport.com/smf/index.php?topic=15249.0
1971’ Flatback 222 - SOLD
1972' 240 Seahunter - SOLD

 

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