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Discussion Starter · #1 · (Edited)
Remember the Rod Baker Port Isaac 42 that is now "Troms Explorer" ?

well, somewhere near his shipbuilding yard, someone seems to be setting up a rival style.

See "Evovle" catamarans (google it) <<<<<< correction "Evolve"

I have it on good authority (better athority, even, than Tom Bettle) that there is nothing new about slim sponsonned displacement catamarans (Glacier Bay model is a prime example) and this is just a new 'hype' of a developing theme.

Still, interesting ........


"Evovle " hah ! Evolve as you notivced !
 

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Remember the Rod Baker Port Isaac 42 that is now "Troms Explorer" ?

well, somewhere near his shipbuilding yard, someone seems to be setting up a rival style.

See "Evovle" catamarans (google it)


I have it on good authority (better athority, even, than Tom Bettle) that there is nothing new about slim sponsonned displacement catamarans (Glacier Bay model is a prime example) and this is just a new 'hype' of a developing theme.

Still, interesting ........
I believe that this new ''hype'' was possibly borrowed a few hundred years before these guys as the polynesians islanders were building and using forms of catamarans long long ago.........still interesting though
 

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maybe, but you won't find it carrying much weight. What's the theoretical maximum speed for a 12m displacment boat?
 

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maybe, but you won't find it carrying much weight. What's the theoretical maximum speed for a 12m displacment boat?
Assuming a waterline of approx 33-34 ft the calc runs out at between 7-9 knots.
 
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maybe, but you won't find it carrying much weight. What's the theoretical maximum speed for a 12m displacment boat?
In round figures, you can use the formula

square root of length in feet x 1.5, which gives you about 10 knots.

However, as you can get 7.5 knots out of a longliner or arran with a 10hp motor, length in metres x 1.5 gets a closer figure (7.2 instead of 6)

So using metres x 1.5 for a 12 metre hull gives 18 knots.

Still a bit off.........
 

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Think more wave piercing than displacement, Toerag.

They don't behave in the same way a traditional displacement hull does, but instead simply slice into a wave like a knife would.
They are completely slam free, in fact they barely bob about, until the wave becomes bigger than the freeboard on the inner edge of both hulls and then instead of slamming on the downward drop they slam as they are pushed upwards. That said, the waves need to be fairly large for that to happen.

They are very economical hull shapes, but 25 knots from 2 x 100Hp is optimistic. You would get about 18 knots top speed, but they will not be governed by hull shape when calculating top speed, unlike traditional displacement hulls.
 

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Troms Explorer had 2 Iveco 270hp (I think) and she did 20/22knots at 2200rpm depending on weather

Martin
 

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Displacement cats, both power & sail, can reach 20 knots.
I looked into building a small displacement power cat (6mt) but decided against it because the slim hulls have little load carrying capacity,
The boats available tend to have very deep tunnels to compensate when the boat is loaded but this means the deck becomes to high & then the boat looks like a barn door!
However this problem becomes less noticeable on bigger cats & perhaps is a way forward in the fuel economy stakes?
 

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Hi

Anyone out there have any thoughts on what makes a good cat and what doesn't?
Whilst we're at it, has anyone heard of BWSeaCat Ltd from Portsmouth? Went on the web and found their site. Older model looked a bit low to the water, but the new one called the SPEED looks interesting, especially for charter work.
Don't have much experience with cats but me and my mate went out on Blythe years ago and that was ok.
 
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