1974 18' Cobalt Trihull

tkinney
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Re: 1974 18' Cobalt Trihull

Post by tkinney »

bruceb58 wrote: Fri Oct 06, 2023 12:08 am
tkinney wrote: Thu Oct 05, 2023 11:33 pmAs for fuel tanks the motor etc. I would be fine refurbishing those.
The problem with fuel tanks, depending on the boat, you practically have to rip the floor apart to replace the tanks. The tanks are placed between the stringers before the floor and the cap are put on during manufacturing. Most boats from the mid 90s on are usually all polyethylene tanks so not as much to worry about them compared to older aluminum and steel tanks.

Out of curiosity, what part of CA are you in?
I live in Seaside (Monterey) , just bought a second home in the Murphys area, so looking at boating New Melones, Don Pedro, Spicer etc.
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Re: 1974 18' Cobalt Trihull

Post by Kate »

"kluge" -- Great word!

"I don't know what an A1G1 is."

First generation Alpha One.

Did I read this right? OMC "mounted the engine and sterndrive on the *stringers* of the boat."

So if the stringers go bad or get squishy, you're in a world of trouble?
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Re: 1974 18' Cobalt Trihull

Post by Kate »

"Tri hull"

There's a good reason why that design is no longer popular. In choppy water, you get beat to a pulp.
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bruceb58
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Re: 1974 18' Cobalt Trihull

Post by bruceb58 »

Kate wrote: Fri Oct 06, 2023 8:35 am "kluge" -- Great word!

"I don't know what an A1G1 is."

First generation Alpha One.

Did I read this right? OMC "mounted the engine and sterndrive on the *stringers* of the boat."

So if the stringers go bad or get squishy, you're in a world of trouble?
Yes...all force goes through the stringers. There is just a boot as the drive goes through the transom.
2017 R5 350HP Mercruiser Bravo III
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Titaniumboy
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Re: 1974 18' Cobalt Trihull

Post by Titaniumboy »

Kate wrote: Fri Oct 06, 2023 8:35 amDid I read this right? OMC "mounted the engine and sterndrive on the *stringers* of the boat."

So if the stringers go bad or get squishy, you're in a world of trouble?
Yes, if the stringers get rotten then you are in a world of hurt. My stringers had gotten rotten in the 1990’s and my boat shop buddy and I pulled the engine. The fiberglass enclosing the stringers had literally become an empty fiberglass shell. I then took it to a shop that repaired the stringer damage.

There was a small amount of transom rot but I elected to delay that repair because the outdrive imposed no forces on the transom.
2007 Cobalt 240 with Merc 496 MAG Bravo 3
1977 18’ Beachcraft with Ford 302 V8 OMC 190
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