fast but lightweight cruiser

Very nice.

 

Those models seem to have worked out perfectly-thanks for the link.

 

Sheeesh.... when & where was that picture taken? I see the dream car of my youth - Morris Minor Woodie in the background. Nowadays I'd take the unfinished hull.

 

Hi Rob,

About the beam mounted rudders... & not having a go, just wondering as it seems to me that it's a less than ideal place them with a long cantilever from the water loads to an apparently close spaced pintle system, I've never seen the details up close though...
I would have thought that the barrel/drum style rudders mounted through that leeward hull would have been ideal for your hulls with little rocker? Is there some patent/proprietary issue with the use, just wondering the rationale?

Regards from Jeff.

 

That is the Cox's Bay Skimmer and I built it maybe 4 years ago in Jacques de Reuck's metal spray factory in Auckland. The Woodie is owned by Mort, one of the workers, a Geordie who resided in NZ for many years now, long enough so we can actually decipher his language; he is part of the film grip team Harrison and Watkins next door who specialize in designing and building exotic stuff for film companies.
Here is another shot of the Skimmer just after launching.

 

Gary,

Wild looking machine there, what's going on with the rig?

Jeff.

 

I bit off more than I could chew with the double unstayed wing masts rig - because I bent the cantilever internal lower section (alloy reinforced with glass and carbon) of the forward one, carrying too much sail in too much wind and wave. So I changed them to stayed setups and have had no more problems. Here's a more recent shot.

 

Interesting the forward one bent, maybe due to greater pitch moments in that location? Great to see some people in the shot, gives a better idea of size... bigger than I thought... a very quiet day..

Jeff.

 

The rudders, and everything else, had to be idiot proof, simple, liftable, steerable and kick-up-able in both directions, with no chance of hull damage in a collision or grounding. The beam mounted ones were the only ones that fit the bill.
I tried barrel/drum rudders on one of the early harrys, and sailed on an 18m racing mono with 2 of them. They are hard/expensive to build, require a large (almost twice the chord of the blade) hole in the bottom and if you hit something, the blade/drum/hull will be damaged. They are hard to keep the weed off and if you accidentally gybe with the board up, the boom may hit it. Any amount of rocker or V in the hull and there is turbulence when you rotate them.

Most of the cruising harrys have the rudders mounted on the side of the hull. After a few iterations, these are working well, and the latest versions are pretty sleek. But the beam mounted ones are simpler, and work well on the lighter boats. I have been testing/breaking/using them for many years on my 7.5m test boat.

You are right, the beam mounted rudders have a longer lever arm, so need more carbon. This is easy to do and is cheap. There is about $400 worth of carbon in each rudder, less than $50 worth total in the pintles.

Two other benefits:
1) You can see the rudder and easily remove weed or plastic bags by pushing a shaped stick down the leading edge.
2) The blades are not operating in the turbulent flow attached to the hull. According to Bethwaite this is a large source of drag. It is offset by being a surface piercing foil, but we have had no ventilation problems with them so far, and if we did, a plate is easy to fit.

rob

 

I knew I was on the right course; and how old is this classic design? - this a Daru Island, Torres Strait, double outrigger with two masts, wide beam, small floats ... just needs some foil support to make this beauty modern.
Posted by Ian McGehee, Small Trimarans journal/web site

 

Interesting picture. I wonder what they used for sails. I wonder how the boat was used. It looks to me like the hull has some kind of skins or sheathing on the bottom. I definately like the seating area in the middle.
Looks a lot like three devils.
nelson

 

This is a Torres Strait design with two masts set forward; I assume for broad reaching and running.
There were double outriggers on both sides of Cape York peninsula in Australia as well as in the Strait - and that influence would have come from Indonesia.
The second double outrigger is from the Philipines.
I'm guessing the double rigged Torres Strait design in the earlier photograph would be a double version of the single rig in the Phillipines tri, since the second/main mast is further aft.
These designs would have been a combination of careful adzing from solid wood and sewn/sealed planks.

 

Daru island double outrigger

On the Monash university animation they have the hull as a dug out log with build ups on bow and stern. Curious hair/grass hanging from the bow. Maybe just decoration? The 3d animation shows paddlers but clearly the photo you posted is a sailing vessel. I am not sure what the seating on either side that looks like couches are. Transporting bamboo? Wind break for chief? Or spare material for making repairs underway?http://www.panoramio.com/photo/14400317
Here is a link showing more of the rig from a daru island boat.
nelson

 

That big double outrigger is a modern interpretation, in the rig that is, because it is conventional schooner (gaff for mainmast) and a headsail. Quite different rigs to the earlier traditional image postings. The two long box shapes I'm guessing are for food and gear storage.
Streaming hand made fabrics/feathers from masts will be decoration and probably important local flag-type announcements - sailors are the same everywhere.
Somehow this thread has veered offcourse - but not really, still linked to fast cruisers - and a few of us are fascinated by indigenous boat design.

 

I had wondered if the rig was different from traditional. I looked just like my old gaff rigged schooner. I bet it sails a lot faster thou. Very small floats on this boat, but they are way out there.
On a cruising boat like three devils how much flotation would the amas have? Looking at some of the more modern tris the amas are huge. Great for light storage but more weight also. The light storage is very useful, there isn't a lot of storage on a tri to start with unless getting above 9M in length.
nelson