One Legged Alien; Jim Luton's design

[David Geiss]

Hi All:

I'm in the midst of an outrigger sailing canoe project and am seeking further information on or the opportunity of reviewing the plans for Jim Luton's 5m outrigger sailing canoe, One Legged Alien.

An inquiry of Jim yields his repsonse that he maintains no plans and that all have been sold.

Anyone out there who has built her or purchased the plans?
Willing to share or barter for plans? I could certainly ask Jim if he has an objection to transfer but I get the sense that he has moved on and has bigger fish to fry.
http://www.watertribe.org/Magazine/...have to then scroll down to archived article from June 2000 (not able to post direct link)

Best,
David

[paladin]

I would guess from the info that the main hull was about 5 feet in beam...16 plus feet loa.....using those parameters, it may be easier to make the main hull from multi chine 1/4 inch ply, laminate the cross beams from fir, build the aka as a "v" hull.....cant the aka outboard 7-8 degrees, and fit it so that with the main hull level, the bottom of the aka is just barely touching the water...perhaps by an inch or two...by canting the aka it is not necesary to build it with an assymetrical shape......you should be able to design the system using a program like plyboats...or by hand as it's a simple design....and start with the weight that you need to carry, then add the estimated material weight......

[David Geiss]

Hi Paladin:

Thanks for your observations. Really appreciate that!

I was not too clear on the post....I'm using an existing frp hull and building a S&G ama to CLC plans using sapele marine ply; here's my message to John @ CLC from a few days ago:

Here is a message I sent recently to John Harris of CLC, which gives an idea of my thinking on this project:

"Greetings John:

Perhaps you recall meeting at the NJ show this past March.
I own two sets of your sail rig plan and and am working through the second plan (never built the first from the first plan).

I am adapting an open canoe (already rigged for sailing); I'm thinking, since I already sail a tri (Fulmar, which we discussed a while back), that I will mount one ama of 10' loa (your dimension from the plan). The canoe, a refinished Lincoln, is 16' loa, max beam of 36"; rather pronounced bilge no tumblehome to speak of.

I realize that this canoe is rather beamy when compared to traditional hulls used as a vaka. I envision this as a tacking boat.
I feel that the rig will sail well with the ama to leeward but I am wondering about how it will behave with the ama to windward; I realize that, in this scenario, the weight alone of the windward ama (and akas) will resist, to some degree, heeling motion to leeward but I am wondering:

-how far, roughly, should I consider as a starting point for centerline distances between canoe/vaka and ama in this scenario?

- how far, roughly, might I extend the akas to the non ama side of the vessel in order to develop a ledge for live ballasted leverage (i.e me!) sitting to windward when the ama is to leeward?

- will I likely be sitting between the canoe/vaka and ama when sailing with the ama to windward?

- should the ama be centered fore aft relative to the loa of the canoe/vaka or should I listen to a feeling I have that the ama should be further to the fore end of the canoe/vaka?

I would really appreciate any thoughts you might be willing to share on this. I hope all is well and that corporatedom does not, to any unacceptable degree, diminish out your sailing opportunities!

Best,
David"

[paladin]

The real problems with designs like this is longitudinal stability....or lack thereof.....this is/was evident in the Piver tri designs from the outset, and several overseas designs....
Rudy Choy did a lot of the big catamaran designs as CSK out of Hawaii, and the first ones had the same problem....Jim Brown solved the problem with assymetrical hulls and a monster bouyant centerboard....Ed Horstman made symmetrical hulls then canted them outward, the basic rule being an arc swung from the crafts centerline through the ama........in your application a centrally located centerboard or a well constructed lee board may be the answer.....best of luck...

[Gary Dierking]

Centerline distances between the hull and ama could range between 4 and 7 feet, depending on the sail area.
If your ama is not buoyant enough to stay afloat when to leeward, you'll have to extend your beams out over the non-ama side. Two feet is usually enough for a comfortable seat.
A lightweight hollow ama to windward is not heavy enough to balance the sail area without hiking out. I use a 18"x 24" hiking seat which rests with its inner edge on the gunwale and its outer edge on a fore and aft pole resting on the crossbeams (aka). Always be sure to be in this seat before you gybe.
An outrigger canoe with a tacking rig (as opposed to a shunting rig) should have its ama or amas oriented more forward, because of the need for diagonal stability.

Gary
http://gary.dierking.net


[quote=David Geiss]Hi Paladin:


-how far, roughly, should I consider as a starting point for centerline distances between canoe/vaka and ama in this scenario?

- how far, roughly, might I extend the akas to the non ama side of the vessel in order to develop a ledge for live ballasted leverage (i.e me!) sitting to windward when the ama is to leeward?

- will I likely be sitting between the canoe/vaka and ama when sailing with the ama to windward?

- should the ama be centered fore aft relative to the loa of the canoe/vaka or should I listen to a feeling I have that the ama should be further to the fore end of the canoe/vaka?

[David Geiss]

Dear Gary and Paladin:

Thanks very much for your great insights. I was aware of some of Piver's tri designs but not aware of any outrigger canoe designs.

I intend to lash the akas to the vaka and perhpas use some type of fasteners for the ama to aka connnection points. I'm open to using lashings all around and don't see that it will be such a drag to lash, unlash, etc.

I'll likely go with between 5 and 6 feet between centerlines in that the sail area will vary between 30 and 60 feet.....average sail area I suppose will be about 50.

I'm approximating 10% to 15% forward of amidships (the center point of the overall length of the vaka) for placement of the center point of the ama lengthwise although I can most likely move that fore and aft as I begin to sail the boat and then settle upon a final location.

I'm thinking that the leeboard (which already exists on the vaka) will be mounted so that it deploys on the port side of the vaka between it and the ama. Then again, I can easily switch that around by reversing and re-clamping the leeboard thwart and see which way feels better. I'm thinking that the ama may provide a bit of lateral resistance as well..maybe not enough to claw to windward on its own but a nominal contribution to lateral resistance.

Gary.....you have confirmed something I thought about early on, that is permitting access to the interior of the ama for some storage and weight to windward on that tack.

I'm even thinking bamboo for the akas but perhaps a composite so that I'll fabricate akas raked toward the sky on the non-ama side (have not figured out how I might get the bamboo alone to curve like that, short of growing it in a jig).

Anyone had any experiences good or bad in sheathing bamboo candy cane style in frp or carbon cloth?

I'm no engineer but trying to follow some tried and true parameters rather than reinventing the wheel. If the craftsmanship of my "wheel" is something to remember then it will be satisfying.

Best,
David

[Todd Bradshaw]

Take a good look at Gary's website. There is a lot of great stuff there. You also might find the article in the "amas" section on building foam-cored amas interesting. Get back to work and get the book done and published soon Gary. The market is ripe.