Small trimarans under 20'

It was a simple request for information.

No need to make a half assed guess.

I asked the same thing to CLCboats about their Kayak Sailrig. That was 100# depressed to the gunwale.

 

Sorry, I just answered to Doug Lord ! I would be surprised if my "guess" was "half assed", perhaps just within 20 % assed. It was a simple computation , based on dimensions you can find on Richard's site. As for Kayak, these are fully immersed floats. I recently immersed my Strike 15 outrigger 1.50 under water, but did not capsized. I Hope Richard will have enough time to give you the exact figure, as he didn't answer to my previous post.

Best wishes

 

The Zeta outriggers are 3.2m long, 300wide approx at deck level and approx 350 deep. Total disp is a bit over 0.12cum

I have now weighed the boat. The main hull weighed 43kgs (95lbs) each outrigger 11Kgs (24lbs) all four crossbeams 8kgs (18lbs) So a total weight ex rig of 73kgs, (160lbs)

It would have been lighter had we used better quality wood instead of wood from Home Depot

Like Patrick I would also be interested in real performance figures over a reasonable distance. Not just peak instant speeds from a gps

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Zeta

Thanks....

 

Today I sat on a Zeta outrigger. I weigh 80kgs. There was about 70mm freeboard left, implying around 0.13cu.m total, as I said before.

We made a 7sqm screecher for our Zeta trimaran and tried it today. As you can see from the mirror like surface there wasn't much wind! It was all a lash up, I have no cleats for mainsheet or screecher so had to handhold everything. But it sailed well and tacked easily. See the video here https://www.youtube.com/watch?v=BUL4QnL7oxo&feature=youtu.be

You can build your own Zeta trimaran from 7 sheets of ply in 150 hours. The boat weighs 73kgs, 160lbs, ex rig. You can see more here.

http://sailingcatamarans.com/index....-under-25/458-zeta-14ft-singlehanded-trimaran

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Congratulation, Richard, very nice looking and sailing Trimaran !

Patrick

 

I just compared the Zeta to the Weta. The latter is 30% heavier! eg main hull 132lbs, all up 220lbs.

So it is still hard to beat a simple plywood hull if you want light weight

Richard Woods of Woods Designs

www.sailingcatamaras.com

 

Chryz Outlaw updated with more sails

I have updated the boat with a larger jib from a 49:er. Tested it out yesterday, and it was running very sweet upwind now with much better balace. Downwind, I still need a lot more sail. Looking for something to fit.
Tested the jib in our local clubrace, and got to the top mark first.
Then... the downwind was another story..
https://youtu.be/766jF0WJugY

 

Race

Clearly you were faster, how was your pointing compared to the bigger monos, were you sailing as high ?

 

When the wind was little stronger, I could point as high as the monos and still have have higher speed. You can see in the beginning after start, I was pointing high, but got little turbulent wind from the HP1030 boat. When the wind was little lower, I could not not point as high with good speed. I'm fairly new to multi-hulls, and I guess it takes time to learn whats give you the better VMG to the top mark.
Just before the top-mark you can see the large Arcona 380, had to go behind me, and clearly they could point little higher than me. But those boats in the race are no boats to "joke around" with during upwind sailing, they are fast and I'm very very happy I could keep them behind for a while with my garage-built little trimaran

Chris

 

hi there
I am going through the design phase of the often done before "trimaran using F18 hulls" combo, and I have a couple of questions:

my first question is regarding the height of the amas relative to the central hull:
option 1: I design the central hull to be at DWL in lightship condition with the amas just kissing the water
option 2: I design the central hull to be at DWL in fully loaded condition with the amas just kissing the water
I have made quick models in maxsurf using both configs and as expected option 1 offers more righting moment, clears the central hull with a smaller heel angle, but has the windward ama closer to the surface for a given heel.
any advice ?

my second question is regarding the shift in LCB when heel increases and the buoyancy shifts from the central hull to the ama. I can design the central hull with the LCB positioned according to my weight estimate, but I have to make do with my F18 hulls which have the LCB further forward, so as the boat heels, the boat pitches bow up by about 3°. Of course this is not taking into account the bow down pitching moment due to the sails but I don't know how to account for this in maxsurf.
I have tried angling the amas bow down by 1° which helps a little but very quickly starts looking odd.
again, any advice ?

some numbers:
central hull length 5800mm
amas 5500mm, volume 780 liters
estimated lightship 260kg
estimated fully loaded (3x80kg crew + tents + beer etc.) 535kg
attached perspective and side view for option 2 fully loaded at 15° heel

thanks in advance for your help !
Jeremy

 

You might find this thread interesting: http://www.boatdesign.net/forums/multihulls/trimarans-angle-heel-main-hull-takeoff-39553.html

What is the overall beam of the boat?
How much sail area:
--upwind
--downwind
Do you want to fly the main hull?

My 20' tri circa 1971- amas were just touching when boat was level:

 

I assume you have talked to Patrick and seen this video of his Strike 20 at a 15 knot average speed?

https://www.youtube.com/watch?v=YWK7cOOtP_U

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

hi Richard
I have actually spent some time looking at your designs and I have watched Patrick's video several times.

but I can't figure out answers to my questions from doing that.