Wooden Trimaran

[Chris Ostlind]

Well gang, this last weekend I took my new design, the A18 canoe/trimaran down to Lake Powell for its first sailing session. The occasion was the Second Annual Lake Powell Messabout and I am overjoyed with the results of the boat's first time on the water.

For one of the first sailing sessions, I took along Chuck Leinweber, owner and publisher of the Duckworks Magazine for Boatbuilders. Chuck
brought his Garmin GPS and we clocked several of the runs we made.

In winds that varied from 13 to 18 mph, the A18 punched in at 13.1 mph while sailing upwind. We didn't get a reaching leg clocked as we were having too much fun to pay any attention after the first set of times were recorded.

The cool part about all this is that the boat is still not setup with its full trampolines from ama tomain hull. This meant that the boat could only be sailed from the main hull. I'm more than certain that when the tramps are installed and I can move out to the amas for counter-balancing, the speeds will easily reach 15+ mph in the same conditions.

The boat is very nicely balanced from the tiller with only the slightest hint of weather helm. She turns smartly through the wind on a tack and gives very good feedback when the leeward ama starts to
press fully under hard sailing loads.

The demountable feature of the aka beams allows the boat to be take apart on the beach and reconfigured for a 6' beam trailering mode.
Standard sailing beam is 15'.

The boat weighs somewhere in the 350-375 lb. range I can't give an exact number yet as I haven't had it to the scales and gone through the weigh/unload/weigh-again procedure. Very specific numbers as soon as I get off my butt and do that.

There are two very informative articles at both Duckworks an Watertribe that deal with all the specific info on the boat along with a nice collection of photos showing the boat under construction.

The hulls are built in a multichine design from 6mm Okuome in the vaka hull and 3mm Okuome in the amas. All the decks are stripped with 1/4" x 3/4" red cedar. The boat is glassed inside and out in 6 oz. set in PTM&W epoxy. I fabricated all the metal fittings in 316 stainless steel. The rig is right off a Hobie 16 cat as are all the sheet trimmers and hardware for sail control.

The overall beam is demountable to a trailer width of 6 feet. Setup for the entire boat is right around 40 minutes without rushing.

You can view a small collection of images from the session at: http://www.dmelt.com/lunadadesign/A18/

lunada9 at yahoo dot com

Chris

[ 09-30-2005, 08:52 AM: Message edited by: Chris Ostlind ]

[Lucky Luke]

Vey nice little craft, indeed

Still, you are breaking one of the essential rules of this forum: no advertising, sales, swap, promotion of any kind...

[Chris Ostlind]

Thanks, Luke

I ammended the posting to delete the references.

Chris

[Hwyl]

Nice job, what are the Aka's made of, looks like aluminium tube.

[Chris Ostlind]

The akas are, in fact, aluminum. To be more precise, they're mast sections from two junked Hobie rigs that broke off at the tang.

I get decent strength (they're waterstayed anyway) they are easy to find anywhere in the world and I'm doing my bit to recycle stuff that would probably just be laying around for another century or so. They also provide the perfect, luff groove tracks for the trampolines.

Chris

[brian.cunningham]

Nice looking boat, but I don't like the idea of straight beams since they hang down too low over the water. I also think the curved ones are prettier.

[Billy Bones]

Way to go Chris! I've enjoyed watching your progress on the various forums! Yes, curved amas are pretty, but I don't think they would work on a boat of this scale.

Congratulations on a well executed design and build.

[Chris Ostlind]

Overall, I also agree; curved aka beams are cool looking and functionally proper, BUT...

When designing a boat of this type, one has to consider the abilities of the home builder who is likely to construct a multihull of this type.

Properly engineered akas with graceful flowing lines require more setup, more expensive materials and more precision in the construction than do straight, aluminum beams that are derived from mast sections one can obtain at virtually any boatyard around the world.

I would love to construct a set of sexy gull wing akas and engineer a method of folding them for transport and storage. Unfortunately, most homebuilders would likely struggle with that process as a first boat effort. This method is easier,faster and more straight forward. There's only a small penalty in overall performance between the two styles.

I'd rather see more of these boats on the water and have the builders smiling from the satisfaction of having built their own multihull micro cruisers than to have several projects sitting partially completed and bad juju around the design.

Just one guys opinion.

Chris

[brian.cunningham]

Or you could just raise the mounts so they're off the deck



Straight akas are great for a folding boat, since you can make them slide out like a drawer like the Sea Pearl

But on a boat the size of a canoe the weight penalty is not worth it.