BIO refit on Crowther Twiggy

[kistinie]

Hi,

I'm very glad to own a Crowther Twiggy trimaran that has already received some modifications and improvments.
i' d like to renew it a little
Boat is west system constructed and sailing well, but time has come to look after arms and amas for keeping it dry and safe.

My 2 main concerns are :

- Getting stronger arms in order to have a more reactive and releable tri
- Taking of as much s.s metal as i can, by replacing it by textile link in a more bio frendly mind

What are the options, or direction a should study
Have you ideas or advices, exemples ?

Sorry for my average english...i' m french :-)

Kind regards

François

[zigzag]

Hi Francois, It may be better to post your message on the mulltihull forum. I recently requested plans for the twiggy design as they are no longer available. There were many responses from people who have previously owned Crowther design trimarans, so you may get more input.

[kistinie]

Ok, how can i do that ? Myself or web master of the forum

An important part of my question is relative to lacing, textile link, in replacement of stainless steal. Do you think it will also be the right place for that ?

[zigzag]

Francois, you are now in the multihull forum, you should get some response.
I thought that you wanted to stiffen up your crossbeams, changing the fittings / fixings to fibre / composite would probably create more flex. I was looking for some plans (do you have plans?) to review as twiggy is a fast boat, probably with a lot of plywood./ glass sheathed. Where was she built? I know french yards have a good reputation for quality work on glass over ply.

[catsketcher]

Hello Francois,

The Twiggy is a lovely boat for the aficionado. It sails well if sailed by a good sailor but may be a little unhappy in poor hands. I owned one for 7 years.

As to your questions.

The beams of the Twiggy are very reliable. I have never heard of any Twiggys having a beam failure. The plywood box beam has large laminations of cedar or douglas fir at the edges of the plywood box. The underwires make the beam a compression member lowering the stress in the beam relative to a cantilever beam. I would not recommend changing the beams unless you have a very good reason like rot. One Twiggy I knew had new beams fitted after rot was found in the beams. Another Twiggy - Like yours a mark 2 had composite beams fitted.

The composite beams designed by Crowther were a little more flexible than the normal Twiggy beams. A friend owned both a Mk2 and a Mk 1 at the same time and found the newer Twiggy more flexible out at sea.

Your Twiggy looks a little heavier than most Aussie Twiggys. She seems to have a fair bit of gear on her. The best way to improve performance would be to get rid of everything you do not need. The lightest Twiggys in Austalia have one float about 250mm above the water on the mooring.

As for getting rid of the stainless - you are best looking around some of the French multis. I have thought that the stainless underwires could be replaced by a composite uni beam. This would be easier to make waterproof than the stainless chainplates that intrude into both the float and main hull.

Getting the correct scantlings for the uni beam should be pretty easy. Ask a composites engineer to design something as strong in tension as the two underwires.

Get back with some more specifics if you have any more questions.

cheers

Phil Thompson

[kistinie]

Thank's for these comments

I will try to get information about composite in La Rochelle.

Beams are MKI wood epoxy made, in one part, but they have a aero cover, in molded wood too. My attention is on a possible water entry on one side.

My twiggy is heavy, mainly because of a yanmar 10 cv sail drive engine with 64 liters fuel tank ! Almost 200 Kg ! So this big engine is the main extra weight problem !
I will sail "wingover" like this first to see if on another hand, it brings an advantage to prevent from pitchpoling with this extra ballast in the back
Th boat and amas has also been lenghted
hat do you think about it ?

In your opinion, what are the main situations i will have to be particuraly careful with my new boat ?

My experience is hobby 15,16, 18 formula with many many (and very often funny)capsize.

Has twiggy comparable reaction to hobby cats, except for fun side of capsize, of course :-(( ?

Kind regards

François

[catsketcher]

Hello Francois

I am not the expert on Twiggy's. I never really raced mine hard but did do a few thousand miles cruising so my background is that of an ex racer using a race boat (my Twiggy) to cruise in. Ian Johnston and Cathy Hawkins are the most experienced Twiggy sailors sailing the original Twiggy to England for the 1982 Round Britain and the 1983 Rhut du Rhum.

In both these races they capsized their Twiggy. She was found after the Round Britain race and repaired but lost after the Rhut du Rhum capsize. Both times she capsized on a fast square run with a kite up. Another Australian Twiggy was the first Twiggy to capsize - she was called Sailmaker and she was the only Twiggy I know of to have her beams replaced when they rotted. Sailmaker also capsized on a square run with the kite up.

I knew Ian and Cathy well when I had my Twiggy. They left me in no uncertainty about their thinking on the Twiggy. They thought it had too little bouyancy up front. Their next boat - Verbatim - was very different. It had vertical bows and fuller sections particularly up front.

Verbatim was drawn at Lock Crowther's office by a darftsman named John Basden. He then drew a new version of the Twiggy that reflected the thinking behind Verbatim. He was going to build one for himself but got into sailboarding too much. This design was released as the Twiggy Mk 2. This is your boat.

There are 2 Twiggy Mk2s in Australia. Neither have capsized. They haven't been raced hard either. One is lengthened a little. A friend of mine who owned one - Spirit - Mk2 with wooden beams - never found bow burying an issue.

There are a couple of Twiggy quirks you should know about - I have to get back to work but email me at

info@foldingcats.com

and give me your email

cheers

Phil

[thorpeboat]

I once raced against Sailmaker and another twiggy called Tarantula in the Townsville to Cairns race. I was sailing on a seawind 24 called sandpiper. Both the twiggy's had mast head kites up in about 15-20 knots of wind and they both broached at the same time and we went between them into second place. There were 12 multi,s in the race the biggest was a 55ft kracken tri and we were the smallest at 24ft.

[Gary Baigent]

Going back to basics, Francois, there seems to be a lot of clutter (junk, dumb weight) aboard your Twiggy - by scrapping weight and windage, you're going to make your boat safer, put less loads on beams and connections ... and sail faster. I mean that hideous radar tower, an excess of rigging and that heavy donk (motor), that stuff has to go. Your stern is dragging from excess weight. A Twiggy M2 is too beautiful a boat to spoil with such unnecessary gear. Just imo of course.