Check this boat out and add your comments...

Nice foundation for the do it yourself kinda guy... or is it...

I'm a little curious about the keel design. And the bulb is formed like a cigarr, wont that increase resistance quite a bit?
It looks like a scaled down VO60 (even the designer thinks that), but the VO 60's are not to fun going upwind. But they claim this is as good upwind as downwind.

Tell me what you think, Below are the details.

Erik

(I'm in no way connected to this designer, just curious on it)


Main data: http://www.polyon.se/alltiett35/
Images: http://www.polyon.se/alltiett35/bilder.html

Rough translation of the details:

Technical data

Loa: 10,75 m
Lwl: 10,25 m
Beam: 3,80 m
Draft fixed keel: 2,00 m
Draft lifting keel: 1,40 - 2,40 m
Displ: 3000 kg
Keel wgt:900 kg (70 % in the bulb)
Main: 33 sqm
Foretri: 24 sqm (selftacking)
Gennacker: 115 sqm (reacher in english?)

Hull is built w. Kevlar and Isopolyester (handlayup)
Specially built keel:
Approx: 900 kg, a 3,6m long keelblade that is fastened in the hull, deck and main bulkhead. This resuls in a keel that can't "swing".
Steel construction w. lead bulb. plastic "halves" of kevlar filled w. plastic and sand wich gives a good weight distribution. [sand and plastic is that good?]

Basic price for the above (hull, deck and main bulkheads mounted): 35.000 USD
Completed it might cost between 65.000 and 80.000 USD

The designer compares it to theese boats:
Sailingabilities like a Mumm 36 (sailingspeed of 12 knots quoted)
Interior space as a X-382
Motoring speed Equal or better than a Swan 45. (9.6 knots w. 5 crew and fully loaded)

 

First impression - it looks like a decent contemporary design to me. The combination of a fine bow and a broad stern has become popular because it works both upwind and down. One does have to be careful to shape it so that it does not trim too much by the bow as it heels, which relates to the LCB/LCF issue being discussed in another thread.

You're right that I would have shaped the bulb a hair differently, but overall the keel looks good.

 

Bulb looks a bit of a weed catcher to me, and improve the streamlining. She also looks a little tender and short on bouyancy forward or there is too much aft, which I think is Stephen's point.

 

Nice!

that boat was nice but its nothing more than that

 

about the keel

I have the impression that a T-bulb is a trickle faster than the more usual L-bulb that extends only aft - there was some research going on about this comparison mainly for Open and VOR 60 boats, and is was quoted that the only reason for using an L-bulb in the end was no-weed-catching, contrary to the T-bulb. Otherwise the T was quoted as faster. Unfortunately I haven't the actual tank-test results or published papers- if anyone does, I'd like to know.
A friend has designed (intuitively, no testing or CFD were available) a T-bulb keel for a 30-footer handicapp racer here, which seems to fair well on the race course .

 

About keel fin designs

There is an article written by Birger Kullman (unfortunately in Norwegian only), that discusses the differences in the keels of the VOR60s.

http://www.kullmann.no/media/norskdesign/V60 S801w.pdf

The constructors seem to have abandonded the L-design shape for the T-shape.

This boat looks interesting, as it seems to be a quite affordable cruiser /racer, considering the size.

Paul-André