tunnel slot design?

[Vulkyn]

Ran into designs for tunnel slot speed boats. Having never seen one or read about one i was curious what advantage they might have over mono hull v planning hull speed boats ....

[Questor]

What is a tunnel slot speed boat ? Do you have pictures ?

[Vulkyn]

Its like a catamaran but the hulls are much closer. Looks like a mono hull with the bottom middle part removed

[Questor]

That's the same hull design as my dollar store, battery powered kitchen sink research vessel.

[Vulkyn]

Originally Posted by Questor

That's the same hull design as my dollar store, battery powered kitchen sink research vessel.

Good for your kitchen sink vessel ...

So any 1 know of this design ?

[Vulkyn]

Does any one know more details ?

[Jeff]

It reminds me a little of the split-vee hulls from 25-30 years ago. (e.g. the arnow 27 split vee or the arnow 39 "blue thunder" sold to customs) - but even less tunnel. Around that time a couple builders were doing something like this -- e.g. from the 1981 wellcraft brochure (attached) the cougar cat (I don't think there were many of these sold here)

[Vulkyn]

Hmmm .... i havent seen any tunnel designs recently, the pics i found are from Glen-L fiberglass design. Looks like old designs too.

[yipster]

a small slot, like smal strakes only gives small lift, but there is much more to it, small hull's (LBx2) etc
more reading on http://en.wikipedia.org/wiki/Tunnel_hull and http://en.wikipedia.org/wiki/Offshore_powerboat_racing
and http://www.aeromarineresearch.com/pu...vDec_2008.html and on this forum
and nice article you have saved there Jeff, nice pics and good read

[Vulkyn]

Thx ! I still do not see if it has any major advantage for speed boats (not racing boats).
For example do they provide addition stability, greater comfort or speed only?

[yipster]

and how about efficiency, yes there's much more to know about them
http://www.boatdesign.net/articles/t...sign/index.htm
http://www.boatdesign.net/articles/d...rust/index.htm
http://www.boatdesign.net/articles/d...nces/index.htm


if you only like older classic shiny heavy wooden speedboats than dont read

[Vulkyn]

If it floats, has an engine then i love it However i am more interested in the every day main stream application rather than specialized fields like racing, or speed records etc...

Very interesting read !! I thought only hydrofoil utilized air lift principles.

The picture i posted does not seem like a tunnel design, there is simply not enough space to create the lift effect and the 2 hulls are very close to each other.
It looks like a squeezed catamaran design. It does seem to my untrained eyes that kind of configuration will have better stability and less tendency to roll. It would also seem that the amount of power needed for a certain speed could be lower than a normal mono hull.
However it might have less weight carrying capacity.
(just my ranting)

Thx for ur links yipster keepem coming please

[yipster]

Originally Posted by Vulkyn

It would also seem that the amount of power needed for a certain speed could be lower than a normal mono hull

your right, getting into and over hullspeed you mean

[Vulkyn]

So if i had a choice between 2 almost identical speed boats for cruising and water sports, why would i choose a tunnel design over a normal hull?

That's what im trying to figure out !

[daiquiri]

Originally Posted by Jeff

It reminds me a little of the split-vee hulls from 25-30 years ago.

I just love the styling of the 70s. I find this boat's lines so simple, yet very appealing.