Modern hirondelle

Perhaps so, other issues though are that the fuller transoms used to counter pitching are draggy once submerged. All these things can be mitigated I'm sure but as I said, swings and roundabouts.

 

I had thought about soft V. It would allow me to do away with lar keels and boards. Makes the boat simpler to build. You don't have to immerse the ends but you do have more rocker. More bouyancy in the middle and less at the ends leads to more hobby horsing, wharrams are famous for it.

It's certainly worth thinking about. Maybe more rocker at the ends and a flatter run amidships. Such shapes need careful consideration. You could make it an even bigger pig to tak if there is too much underwater toward the ends..

The thing is hirondelles have round hulls, are 7 meters long have 5'9 or 10 in the hulls and don't look boxy. It should be doable.

It's been incredibly hot here lately and promises to be for the next week (and I've been sick). When I get some time and the weather isn't against me I'll try and model something up.

 

Besides the greed for speed there has always been the greed for headroom with multihulls. Here is an old design (not modern) of the sixties from Charles Greene "BOATBUILDING without brainstroms, blisters or bankruptcy": Six ft headroom in the hulls and in the cabin with lifted hatch at a length of 20ft o.a.. O.K. it is not so easy on the eye, but seems to be easy on the pocket and fast to be built. I do not know if somebody has ever built this little "Sea-going" Catamaran which is claimed to be trailable.







http://the-norfolk-broads.co.uk/viewmessages.cfm?Forum=25&Topic=23228

Trailable like this 22ft long and 12ft beam trimaran from Chales Greene:

 

Thank you for posting those.

I'm tempted to say hilarious, but it was through people trying stuff that we found what works and what doesn't on multihulls, so I guess we owe them.

I do think we have arrived at a set of magic numbers, a range of values for all sorts of bits in multihull design. These days designers don't stray too far. Maybe that's a bad thing but the magic numbers do tend to result in a good all round boat.

Off the top of my head:

cat beam to length around 60%, mast to length 1.2, hull beam to length cats 10:1+, tri main hull 8:1+, floats 15:1+, prismatic over 60, bridgedeck clearance about 14% of beam. What others have I forgotten ?

 

Lol, love it ! I love reverse shear.

And....a square top main !

 

It's fabulous isn't it...

 

In my part of the world that cat would be referred to as a "Rotto boat" with reference to Rottnest Island 18km offshore. Big on accomodation, not so big on seakeeping.

 

French multihullers would say: "Ils sont bizarre - les anglais!" But I love it. It looks so sturdy and stubborn. The leeway reducing steel plate, the neat rudder, the way to trail it, the wigley hulls .. all is so... individual and unusual. It is .. ..ah .. different and that attracts me. But I would not build it.

Though it is easy to build:

 

Multihull design, construction and materials have come on a long way since those early designs so nice to look at but don't touch!

 

I think it is O.K.. If you want it more professionally there has been an interesting thread: http://www.boatdesign.net/forums/multihulls/how-dimension-sailing-catamaran-22274.html or http://www.multihull.de/technik/catdimension.pdf .
For a small catamaran: http://www.boatdesign.net/forums/at...021-how-dimension-sailing-catamaran-catxl.jpg .

Another oldie

of the seventies from
Fareham Boat Plans GB

 

Thank you for the pointer to that thread, I'd not read it before.

I love the domino. Very similar to a hirondelle.

 

May be you have seen it already, Richard Woods has done the plans for a nice little catamaran for day sailing and the possibility of overnighting under a cockpit tent: http://sailingcatamarans.com/index....s-under-25ft/475-chat-18-daysailing-catamaran .

http://www.sailingcatamarans.com/images/chat18stplan.pdf

 

Old plans

Manfred; Where are you finding all these older designs ?

 

Thank you for pointing those out to me. I am well familiar with Mr Woods website, probably too familiar. The designs that most appeal to me are the eagle and elf, both of which are larger but offer a lot more headroom. They would need to dismount for trailering.

The point of my origional post was to suggest a 2.9 meter wide mini bridgedeck might manage 6' headroom and be seaworthy enough to cruise the queensland coast.

This is somewhat off topic, but it comes back, bear with me.

Despite sailing since the 80's I'd never sailed a dinghy until today. I bought one on a whim a few weeks back, a 10' snapper class fiberglass dinghy. It has oarlocks and can take up to a 5hp outboard. I thought it might be a versatile boat.

Finally got to take it out today. Absolutely hated it. Even in no wind I was concerned the whole time about balancing the boat, ducking under the boom was a nightmare every tack. and that mainsheet...I didn't mind that I wasn't going fast, and the boat tacked readily despite almost no wind, but compared to a beach cat it was just awful. I understand everyone is different but I've learned that dinghys are not for me...

So I'm looking hard at Tryst/Duo. It looks like a remarkable little boat. Mr woods has solved the contradictions between a row boat and sail boat by adding outriggers, floats.

So the snapper goes on gumtree and if I can find a buyer I'll build Tryst. I must ask if there is a tryst builder/owners in Brisbane or surrounds and perhaps get a look at the boat. Maybe even a sail...

Redreuben:

Manfred; Where are you finding all these older designs ?

Yes! I'd like to know aswell!

 

The answer is simple. Old guys have old stuff esp. if they are not able to throw it away just in time like me. Here are the two catalogues:



Might be you can get them from "ebay" or "abebooks" or.. But it is not possible to buy the plans - as far as I know. The last catalogue of these I`ve bought in 1971.
And of course it is better to buy a newer plan as there have changed so many matters in knowledge, construction and materials. Richard has a lot of experience in sailing, designing and building. Years ago (1980ties) I have visited him and was very impressed by his work.
Tryst/Duo is a good choyce in my opnion as I´ve found out for me that a small boat offers best contact with sea, waves and wind and the work is kept within effordable limits. I´ve sailed catamarans up to 12m und Trimarans up to 8m but the most fun were the small boats. The work/service/cost and fun rate is a lot better in a smaller design. Nothing can give you back the lost time for building and fitting out a boat.
I have never sailed a ten feet dinghy. The smallest boat for me was a 14 ft Cat built for Greece and the next a 16ft skiff I had built in three weeks for vacation in Sweden. Both boats were self designed and selfbuilt and gave a lot of fun. Old Surf Sails were used and were cheap and effective.

Trail (3000km) and sail: