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**Steve Rust** · 18-08-2007, 17:40

One thing I have not seen mentioned that I am curious about is the bouyancy of the amas as a percentage of displacement. A pure sailing tri would be between 100 and 200 percent, cruisers at the low end and racers at the other. With the power tri and reduced rig can this even less than 100 percent? How and what percentage did you arrive at?

One aspect of overloading a trimaran is how it changes this percentage increasing underwing pounding(solid wing) and reducing stability. More of a concern in the open ocean and large waves where you need the ama to ride up and over and not stuff the ama into a wave and trip the boat.

It has been interesting watching your progress.

beau · 18-08-2007, 21:21

an interesting question, steve.
As you are aware designing boats is always built around compromises.

I must admit the ama designs came last, and were increased in size by my structural designer.
I would have liked the ama's to be smaller and deeper, but they had to fit inside the 40 ft container.
From MY point of view they are TOO large, but time will tell. This is a Power trimaran, but I will sail as much as possible but only on a reach or downwind. There will not be a lot of pressure on the ama's, they are mainly for stability purposes.
I do not expect any pounding on the struts and the waves will flow over the ama's. I did increase the width of the overall boat to counter the smaller size ama's.

As you are aware this is a very different boat and I don't expect to get everything right first time. I appreciate your comments and would like to invite any other comments negative or otherwise.

**Steve Rust** · 19-08-2007, 09:57

Back in the 1990's there was a circumnavigation by a power trimaran. They had some sponsorship from Yamaha as they used that brand of twin outboards. It was coverd pretty well by Multihulls Magazine. I recall the amas seemd smaller than one would expect on a pure sailing tri. It had no sailing rig at all. Did you come across this story in your research? I have sold my collection of the magazine but back issues are available.

I like the design of the crossbeams, they look good and should be quite strong.

beau · 19-08-2007, 14:51

Steve,
Yes I am aware of that particular boat. Endeavour 40 I think, it motored from Los angeles to Hawaii. Long narrow hulls (16-1 or similiat) not much room inside, and yes the floats were small.
I do think the design of the endeavour did influence me, even though it was some time ago.

I do intend to sail, as often as the conditions suit (to save fuel) but I think the design of modern rigs have "lost the plot" They are based on Racing designs to get that last 1/2 knot. And they cost a fortune to buy and maintain.
Now I don't want to roll about at 5 knots for weeks on end either and I appreciate why designers offer a faster sail rig.
However like a lot of things on my boat I think there is an alternative.

I am having a very basic rig, an Oceanic Lateen (crab claw) because it is SO simple and aerodynamically efficient (delta wing) The main part of the sail is in the right place, up high, where the wind is. It is very easy to make DIY and repair and CHEAP.
The disadvantages is that it is not so good upwind and it is difficult to tack, which is why I have two rigs one for each side. The mast is also short which makes it easier to lower. Mine is 20ft long a piece of aluminium tubing which cost $150. The spars of the sail can take the overall height up to 35 ft
Also I intend to motor sail, the Hondas at 1/4 throttle can hardly be heard

TaoJones · 20-08-2007, 13:01

From 'Lectronic Latitude comes word of a broken record for the trimaran IDEC:

"Joyon Takes IDEC Out for a Record-breaking Spin

August 20 - The English Channel

IDEC, the bright red beast, seen here during its first public outing in France last month.
© 2007 François Van Malleghem/DPPI/IDEC

"French multihull multi-record holder Francis Joyon smashed another record over the weekend . . ."

For more, go to:

Latitude 38 - Northern California's Premier Sailing and Marine Magazine

Sure enough, Beau, no bow wave. Is this what we can expect to see from your trimaran after she's splashed and sea trials begin?

TaoJones

Whimsical · 15-09-2007, 17:59

Bump
How is it all going Beau
Mike

beau · 16-09-2007, 14:19

Mike,
thank you for asking.
Almost finished, two weeks to go.
I was held up getting the ply veneer I needed to finish.(new Guinea Rosewood)
The plumbing is all finished with gas hot water etc but the fresh water pump is a little small for use in the shower, so I may need to order another one.
I have set up the 13 HP electric start Chinese honda driving a 200 amp alternator and it seems to work well. I have used a Xantrex regulator. but I have only seen 50 amp so far as the battery bank is at full capacity.
The 3000 watt Inverter I bought from ebay doesnt work, so I may have to buy a new one.
I have used a 240volt fridge and freezer plus a 9000btu Inverter type air conditioner , all are working well off shore power until the new inverter is fitted.
Windows to go in, an a final coat of antifouling.
Once the boat is out of the shed I will post some updated photo's.

Overall, I am pleased with the aspects of the boat, though I can't wait to test it in the water etc.
I designed the layout for two people to live on board with a large covered and screened aft deck, and with the double decker aspect of the boat we have plenty of storage on the top deck for dingy, crab pots etc

It did take longer to fit out than expected, and cost more too, but I have also added a lot of extras like davits, swim ladder, enclosable bimini AND A RUDDER.
Plus my other half has been a bit "picky" in regard to "the finish" and I have had to get professionals in at times to "give her" the quality finish she "demands"
Christine has been involved with the fitout from the start, which I think has been good, and she feels very much that it is "her" boat as well which I think will help with our cruising plans

DtM · 16-09-2007, 14:47

Christine has been involved with the fitout from the start, which I think has been good, and she feels very much that it is "her" boat as well which I think will help with our cruising plans

Never was a truer sentiment expressed.

Good luck, enjoy.

beau · 27-09-2007, 00:43

Just about in the water.
Next week I hope.
All the electrics are now working after I had to replace an Inverter that I bought from ebay that was a dud.

I received a lot of advise from this forum in regard to the electrics, MOST OF IT ********, thank god for Rick how pointed me in the right direction.

I have a 13 hp Chinese Honda running at 1/2 throttle putting out 190 amps into my 800 AGM battery bank. I haver a Xantex regulator and Xantrex gauge for reading battery level etc.

I also have a 9,000 btu Panasonic air conditioner (new Inverter type) which pulls a maximum of 50 amps when the compressor is starting and running.
All this with no gen set running.

I must admit a lot of people (including my marine electricitian) said this combination would not work. but is does, brillantly.
Thank you Rick for your advise.

The boat comes out of the shed next week, to fit the mast and oceanic lateen sail.
I have fitted a rudder.
Photos next week.
Beau

beau · 28-09-2007, 00:13

Photo of my 13 hp Chonda driving a 200 amp alternator. The flexible exhaust pipe is rated for a wet exhaust and mine is dry so I have to find something else.
Any suggestions?
The other photo is of the top deck helmstation looking forward. instrumentation include a 12 inch gps plotter/sounder plus a 24 mile radar overlay.
Hydralic steering and a autopilot.

**GordMay** · 28-09-2007, 02:44

See ABYC Section P1:
INSTALLATION OF EXHAUST SYSTEMS FOR PROPULSION AND AUXILIARY
Goto: https://www.americanboatandyachtcoun...ttees/P-01.pdf
Specifically: 1.8 DRY EXHAUST SYSTEMS (Page 6), and Table 1 (page 7)
ie: carbon steel, nickel-chrome, nickel-iron-chrome, or 316L Stainless Steel

44'cruisingcat · 11-10-2007, 20:45

Bump - How's it going Beau?

beau · 13-10-2007, 16:53

HI sean,
The boat was supposed to go in the water on Friday but apparently we didn't fit on the cradle they had provided so we will use a crane on tuesday or wednesday next week.
We have been held up on getting a couple of sheets of New guinea rosewood veneer which arrive on Monday so we can finish off the interior.

Mast is up and the sail, an oceanic lateen (crab claw) is made.

Finishing off has been a hassle, we have had to use contractors on some of the fit out. They are expensive and unrealiable but I am just not up to some of the skills needed.
Overall I am very happy so far with the overall concept, but can't wait to see where her float lines are, because we have added a bit of extra weight in the stern.
More photo's and details next week.

Saildoggie · 13-10-2007, 18:18

Looks really cool.
Very interesting project for sure, been watching this one for a while.
I really can't wait to hear the sea trials report.
Live your dream, your boat will turn heads anywhere it goes!