so I'm looking at possibly making a wider beam for my ufc catamaran.
it'll be biplane rigged and wider would make it more stable.
Just how far could I go? 9, 10 feet? (from the existing 8')
Fitting on a trailer would not be a problem
as this is a folding design (which I'm still working on)

thread to ufc 1200 boat

most cats pass a stability threshold at twice the length to the beam given the height and power in our sailplans...more beam means the boat is more likely to pitchpole. Lifting foils and lower centers of effort in the sail plan can help reduce the pitchpole resistance.

In your case, with the twin rigs, stability should be a little better since the drive of the sailplan is lower to the deck and my first thought would be to target a 2:1 ratio. I don't recall how long the hulls are you are considering but if they're 18' long a 9 foot beam would be as wide as I would go...which gives you plenty of space.

I did watch your portage video using what appeared to be a couple of prindle hulls and that was pretty interesting. I thought it would be harder to move those around like that. That is pretty encouraging and I wonder if you might not find it necessary to fold the boat when navigating some of the tight river/creek part of the course.

One thing I'm interested in is how you're going to design the hinges on the beams for the pivoting/folding operation. The beams, and specifically these hinges, are going to take a lot of abuse and will need to withstand a lot of wracking forces as the boat goes through waves and chop. Even a light chop will constantly try to twist the beams back and forth, fore and aft. I think this would be the trickiest part to get correct and build something that will withstand the stresses it will endure without fatigue.

Have you looked at Yves Parlier's bi-rigged catamaran, Hydraplaneur, that he constructed several years ago? Obviously it's much larger but he did hold a solo speed and distance record with it for a short while. The bi-rig has some weaknesses when one sail shadows the other on particular points of sail. He had rigged up a small headsail on each mast that he could unfurl to help the leeward rig breathe a little better. http://www.youtube.com/watch?v=AY0ssDA70gY

Also don't discount some of the rig stability you can build in (and reduce the structural reinforcement needed in the decks) if you rig some x-bracing between the masts. Hydroplaner has it as does the Hobie tri-foiler.

Jake,
that video of Hydraplaneur is just awesome! stuff like that is really inspirational ......

and yes, you pegged it, those are prindle 16 hulls and will be my development boat where I can pretty much do anything I want to it testing out ideas and features and not care much if I mess things up a bit.

An example of that is multiple mast placements. For long stretches of single tack I could have the masts staggered? It's an idea, one of many ......

but back to the width subject, for the 16' of the prindle, then 8 is pretty much ideal then? my next boat I'd be shooting for 18' hulls I'd think, and preparing to have a crew member along.

I'm glad you liked the portage test, as crude as it was, it worked well. Video can really tell the story huh? so 16' was pretty easy, next I'll load it full of simulated gear and try it again but with a better set of wheels and dolly setup. I feel confident that 18' will pull pretty nicely too.

The folding feature I have several ideas at work for. My square aluminum tubing ideas will happen after my laminated ply models prove what I'm trying to do. Again, the prindle will be doing all the proof of concept work. Heck, it might even do the my first ufc and ec races, though I got great testing grounds in my backyard for testing.

and for going up the narrow sections of the St. Mary's river I'll have to be in the full folded mode to get thru. When folded I'll be as narrow and only a bit taller than a expedition canoe, and maybe presenting a smaller footprint overall as they are usually setup as a trimaran and have to disassemble and somehow stow it all.

As for the rigging, I hope not to use any bracing , if I can get away with it. I see in some of the biplane rigs they use bracing, so only testing will tell if I can get away with it or not.

stay tuned, I'll be sharing more videos as development progresses. I thought about doing a blog, but I think I like the forum interaction as a better way to share this design adventure. besides, I get some great feedback from you guys!

I like the staggered mast idea. How about large windsurfing rigs. Maybe socket the masts through the deck.
I just read the book "Without a paddle" (by reccomendation in the other thread, Jack I think) and have to say it's one of the best books I've read in a long time. Read it in less than a day. It definitely gives alot of insight into the portage and river sections. Makes me respect what the Crazy Russian did even more.
We( Weta importer,myself and a couple of other folks) had planned to do the Everglades challenge on Weta Trimarans but it never came together.

Tawd

I like the windsurfing sails idea too, but it's not gonna pass "code" per the rules of reefing with watertribe. Though I will most likely try them out anyway. A pair of 8.0 sails should do the trick I'd think. I'm gonna have to find out a way to make a roller reefing main, and I'd like to use windsurfing masts, (which I got plenty of) .
I'm gonna have to get that book too .......

There used to be a company called Multisail that made windsurf sails that had a zippered lower panel that was removable to reef. Maybe something similar could be constructed.

Dave

I haven't read the rules for the FC but,if you have two sails and remove one that seems like that would be a 50% reef.

history about the multisail and it's designer

this would pass "code" as it had done so on a expedition windsurfer last year's EC

you'd might think so but .....
according to the dang rules it doesn't fly ....
I'll go did them up and share them.

(thanks crazyrussian, I robbed this from your post on watertribe)
link to watertribe reefing thread
Here are the current rules:

Reduction of Sail Area All sailing boats must have methods for reducing sail area while underway.
All boats with sails over 1 sq. m. must have a practical, tested means of reducing sail area for strong wind. Sail reduction must be possible while under way in rough water, without causing loss of control or stability, or other danger to the crew.
Boats must be able to reduce sail area in increments of not more than 25% of total working sail area, by any of the following means: Slab/jiffy reefing, zippered panels, roller reefing, lowering/furling/removing one sail in multiple-sail rigs, or replacing one sail with a smaller one in multiple-sail rigs.
A storm sail that is set in place of the mainsail is allowed but does not qualify in meeting the above sail reduction rules.
It must be possible to reduce sail area to 60% of total working sail or less. The boat must be balanced, controllable and able to sail efficiently to windward under the reduced sail plan. Sailboat crews may be required to demonstrate sail reduction techniques during pre-race equipment check.
Exception: Boats with under 4 sq. m. (43 sq. ft.) total sail area may elect to have only one reef which reduces sail by not less than 20% of total area, but are encouraged to adhere to the general standards as above.

The trimaran I linked earlier had a furling main with vertical battens and the sail area can be reduced as needed via furling.

The EC reefing rules are pretty strict. On a typical beach cat, you will need two reef points in the main. Then you can meet the rule with a combination of with jib, reefed, main, without jib, etc.

triak sails page
Interesting design ...
but the triak sail is only 40 square feet, 3.7 sq m
I need bigger ....
Can I make this ?
or have it made?
It's design sure looks like what i'd need.
And it would roll up and stow pretty easy.
I need more detailed pics and info on this .....



btw, the Raptor16 (and 17.5) is now out of business .....

Keep the platform narrow your beams will need to be heavy to work anyway with the hinges etc. Making the boat overly wide will only increase weight. If you are having two short masts you'll have less heeling moment than the original boat had. So there is definately no reason to go wider.

Unless you consider the amount of time you are going to spend on this thing!

And that note really hits home!
I did a 20 day kayak trip up the texas coast in may ....
that kayak got to be quite uncomfortable at times!
I was always wet, it was a tight fit .......
and I thought of ways to live at the other end of the spectrum.
I thought up this boat along the way.
Relatively speaking,
the ufc won't be a race as so much as a luxury boat cruise!

How about a Mirage Island Tandem mast and sail.
Sail Area: 90 sq ft / 8.4 sq m
http://www.hobiecat.com/kayaks/mirage/tandem-island/

I wonder what those cost?
my design and development would be done ...
stick it in the mast base and go sail!
and 8.4 is about the max for windsurfing sails anyway.
but is 8.4 gonna be enough?

That only depends on how fast you want to get there.


A rotomolded boat is going to be heavy. FRP is the way to go.

I just wanted to use the rigging from the AI ,
didn't want to use the boat, not at all!
I'll build up my prindle 16, because it's what I have,
and I don't feel bad about making mods to it ....
but later I'll come up with maybe A-class hulls
or something like that, and really dial it all in.
I gotta start somewhere though.

Here's a reefable unstayed biplane rig for you:



http://www.petegoss.com/userfiles/team_philips_bk.pdf

Despite its problems and early demise, Team Philips was an amazing boat.