Modern hirondelle

[sailhand]

Talk to the guys at sydney rigging i have always found them to be the cheapest they also have stainless heavy thimbles to suit

 

[Manfred.pech]

I need to repair some stuff. One of the shrouds has a broken strand. I'm weighing up whether to replace them in stainless or dyneema.

A number of people have recommended against dyneema, but I'm thinking about giving it a whirl. It would be good splicing practice, the money is about the same and not very much. I've cut my hands more than once over the years on a sharp crimp or broken strand. It would be a cheap experiment and if it's no good it's only another $100 to change it back.

On the other hand I've never made stainless shrouds myself and am not confident doing it. You have to make the pairs exactly the right length I suppose...

The sail is totally shagged, and I lost a batten. I've got a second hand hobie sail in the post which I'm going to cut down.

So I won't be sailing for a few weeks until I can get the work sorted. And I'm going into hospital on friday so that will put me out of action for a while.

I'll let you know.

I did a sailing report here:

http://www.catsailor.net/index.php?/topic/7696-v-35-sailing-report/

It might give you a laugh. I'm not normally that incompetent, it was just one of those days....

Thank you for your report. I can understand that you wanted a first sail with your new boat. But desaster can happen. Hope you will have better times.
I wish you all the best and a quick recovery in hospital.

 

[guzzis3]

Thank you to both of you. It's all good

If your interested I'll post something once I've got some stuff sorted.

Went a bit made and bought 3 old catsails. Looks like I'll be breaking out the sewing machine and trying to remember how to use it...

 

[Manfred.pech]

Thank you to both of you. It's all good

If your interested I'll post something once I've got some stuff sorted.

Went a bit made and bought 3 old catsails. Looks like I'll be breaking out the sewing machine and trying to remember how to use it...

Yes, very interested. Thank you.

 

[guzzis3]

I've been busy but finally got back to doing some modeling. Here are a couple of views of the hull plus a really rough drawing showing some dimensions. It actually looks pretty good so far.

I've been doing some measurements and calculations to do with trailering and launching a cat with open deck and LAR keels. The local ramp only falls 1 in 10, so you'd have to push it out a LONG way to get it to float. Even with boards the trailer wheels are an issue. So I had another close look at the tristar 24, which is about 12' on the trailer and oversize. That's ok but I've emailed Mr Horstman twice this year and no reply. Maybe he doesn't want to talk to me or maybe he's not supporting his plans anymore, or maybe he's sick. I don't know, but I'm reluctant to spend $880 on plans which I'd modify anyway if he's not available.

Conversely I've done a lot of clacs on this boat and everything just seems to fall in to line. So far....

As previously mentioned 7 metres long, 2.9 wide, 1.75 headroom atm. Divinycell 3/8 on vertical surfaces 1/2 on horizontal with 600 gsm 45/45 both sides.

Be aware I've got a lot more bits to chop out and finesse on the model, but I thought I'd post this for any comments ?

 

[Manfred.pech]

I've been busy but finally got back to doing some modeling. Here are a couple of views of the hull plus a really rough drawing showing some dimensions. It actually looks pretty good so far.

I've been doing some measurements and calculations to do with trailering and launching a cat with open deck and LAR keels. The local ramp only falls 1 in 10, so you'd have to push it out a LONG way to get it to float. Even with boards the trailer wheels are an issue. So I had another close look at the tristar 24, which is about 12' on the trailer and oversize. That's ok but I've emailed Mr Horstman twice this year and no reply. Maybe he doesn't want to talk to me or maybe he's not supporting his plans anymore, or maybe he's sick. I don't know, but I'm reluctant to spend $880 on plans which I'd modify anyway if he's not available.

Conversely I've done a lot of clacs on this boat and everything just seems to fall in to line. So far....

As previously mentioned 7 metres long, 2.9 wide, 1.75 headroom atm. Divinycell 3/8 on vertical surfaces 1/2 on horizontal with 600 gsm 45/45 both sides.

Be aware I've got a lot more bits to chop out and finesse on the model, but I thought I'd post this for any comments ?

Thank you for sharing your ideas with us. Is the design program able to give numbers about centers and displacement of the hulls? I fear the hulls are a bit too slender for the cabin and the accomodation??? within 7m length.

 

[guzzis3]

Thank you for the reply.

The cad package I used for this is a mechanical one and isn't as convenient for boat modeling as it could be, however it does give me a very accurate volume to whatever waterline I nominate. Using RD water = 1 the displacement is about 1150 or so kg with the transom and bow just touching the water. I'm still working out what the boat will weigh, but I think 600 - 700kg is a reasonable range. For now I've got a 600 beam on 7 m length. I could increase that to 700 for 10:1 but it actually makes them more buoyant than I think is ideal. Maybe I'll settle on 650 or something. I want about 500 kg carrying capacity, I think that's reasonable for a coastal cruiser, so when I know roughly what it will weigh I'll tweak it for that. Also the prismatic is high. I'm not sure how high but probably about 60 or so, which should help with hobbyhorsing.

I have not added the LAR keels yet which of course will change everything. My thinking atm is 2.5 tapering to about 1.8 and 450 high. Probably the thing I am least confident about right now is the layup of the lar keels. I want to make them strong and rugged but don't want to add unnecessary weight.

I'm looking at something similar to a tornado rig. Either way it wants about 20 - 23 sqm of sail.

Progress is slow. There are many many calculations and decisions to make and I have other things I need to get done in life, so I apologize for that.

Next I want to get the cabin and accommodation closer. I'd like as nice a spaces inside as I can get within the envelope, but I'd like to make it acceptably pretty (not something I'm good at) and of course consider windage.

 

[Manfred.pech]

Thank your for your helpful explanations. I´ve designed and built 3 catamarans, but none with a cabin. So I tried to find examples for 6 to 7m catamarans with overnighting and cruising accomodations. But aside from the well known ones in Australia (Jarcat for inst.) there were not many to be found.
Chris Ostlind designed 6,5m EL GATO which I found interesting. One of them had been built in Greece and I watched the building of it in another forum. Here
are some pictures of the Cat Duckworks - Gato Especial http://www.duckworksmagazine.com/08/designs/gato/index.htm .
Roger Mann who has designed, built and flown small planes switched over to multihulls and has drawn and built a RagWing Catamaran of 6m with remarkable living
space for the length. Islander Catamaran | PuddleCat Catamarans http://rogermann.org/puddlecat/designs/ragwing-islander-catamaran/

From these pics I think it seems to be possible to built a small cat with standing headroom and enough space for sleeping and living without too much windage.
I hope these examples can encourage you to continue your design work and the calcs for your 7m catamaran.

One professional 24 footer: M24 - Gallery http://www.starshipcatamarans.com/html/m24_-_gallery.html

 

[rberrey]

Not sure if the Sprited Designs STOW - AWAY 7.5 cat has been listed before , but it might fit your needs .

 

[guzzis3]

rberrey: Yes the stowaway has been mentioned. I don't like it at all. Deep V hulls, over styled cabin, poor use of space and incredibly expensive kit.

Manfred.pech: I have corresponded at length with Chris Ostiland on the yahoo group and possibly on the old multihulls forum. Some of his stuff is nice but I'm trying to maximise the boat in a limited envelope, prioritising the things that matter most to me. I was happy to do without a dinette but wanted that full double. I was pleasantly surprised when I saw the sloping cabin front gave me both. With Gato specificalle I think cats this size work a lot better with twin companionways, the boards waste a lot of space in a small cabin (obviously lar keels bring other problems). Thank you for the link to the M24. I had not seen that before. I had seen puddleduck. I don't like plywood and that boat seems a bit crude, but it's very much along the line of what I'm chasing. The hirondelle is the closest though. The biggest move is away from the cabin shape of the hirondelle and pushing the sides right out, removing the side decks. My boat is longer on the waterline and 6" narrower due to the towing limits.

I have completely remodelled the hull but am only half done. When I have something I'll post some more pictures and drawings.

 

[Manfred.pech]

Thank you for your answer. It is very interesting for me to watch the birth of a multihull design to personal requirements. Hirondelle is a well balanced design from Mk I to MK III (boards to low aspect ratio keel) and the total redesign with 25 ft over all. But I do not know if it is still alife. MULTIHULL INTERNATIONAL reported about the
Hirondelle but it stopped and there are no new issues since long time.

Mk III with keel-

 

[cavalier mk2]

The mk1 was a fast nimble boat, I'd hate to lose the shoal draft of the board version and the speed.

 

[Manfred.pech]

The mk1 was a fast nimble boat, I'd hate to lose the shoal draft of the board version and the speed.

Yes, mk1 is a fast and nimble small catamaran drawn by Chris Hammond - within its limits and if it is still alife. Three hundred were built before the company ceased the production in 1983.

But a lot of customers wanted a family boat with more interior living space and accomodations. This was the reason why the smallow resurrected with the help of David Trotter who bought the molds 1990 and with the help of Chris Hammond and Merfyn Owen "modernized" the boat to HIRONDELLE FAMILY . Sail area was enlarged as the beam from ten to 12 ft (!), more room and headroom in the hulls and the bridgedeck.
Under water the daggerboards and rudders were replaced by fixed keels and underslung spade rudders. The new keels are "8ft long trapezoids with NACA-0012 sections, 12,5 inches thick at the base, and with horizontal end plates are now 10 inches wide. These keels are hollow and provide over 600 lbs 0f buoyancy, which is reduced to around 450 lbs of buoyancy when the water tanks in the keels are filled. The effect of these new keels is that the Hirondelle has no tendency to pitch and enjoys a very small leeway. The Rudders, formerly transomhung, have been moved inboard and are now spade rudders with the same NACA section as the keels."
"Even though the boat is larger than the original version, at 2500 lbs, it is 200 lbs lighter, owing to the of plus/minus biaxial stitched cloth over a 12 mm balsa core. Solid laminate is only used blow the water line."
"A Prout-type nacelle has been added to the underside of the wing deck. This encreases strength, helps prevent slamming, and gives extra legroom underneath the dinette table. Seating is being lowered by two inches in the current mold modifications."
(Joseph Norwood, jr., Swallows Return, pp 61, MULTIHULLS , Sept/Oct 1994)

 

[guzzis3]

Thank you for the replies. I am a member of the hirondelle facebook group and yahoo group. I've read all I can and corresponded with owners but despite this I had not read what you have posted above.

I know about the mk1, 2 (shorter mast), LAR keel 3 and the 12' beam family, some with the unusual rig (can't remember the name atm). I did not know they did a 25' version. There was one built at I think 29' but it was the only one.

NACA-0012 is an awfully full section. I had thought of using a slimmer section for less drag, but a thick section like that would allow water tanks in them which would be really handy, as well as "anchoring" the boat in a seaway.

Still pondering the layup for the keels. I need to make them strong enough but not ridiculously heavy. I'll post some more pictures when I get the chance. I've done some more work but these last few week have been quite busy.

cavalier mk2: Thank you for your comments on boards vs LAR keels. Everything is a compromise.

I am always grateful for comments and suggestions.

 

[Manfred.pech]

Thank you for your kind acceptance. I`ve read about the 25ft version in MULTIHULL INTERNATIONAL but did not find the issue again - sorry.
You mean the AERORIG ( or Swing Rig or Balestron Rig). There have been tests (Yachting World/ Practical Boat Owner) between it and the normal one f the Hirondelle. Though the Aerorig (at 212 ft² - 19, 6948 m²) had less sail (33ft² - 3,0657 m²) area than the standard rig ( 245 ft² - 22,7605 m²) it was faster and more handy but the margin was about 1 (windward) - 2 (off the wind in light airs) knots and it is expensive and not so easy to calculate the bulkhead for the unstayed carbon mast.
I do not think that NACA 0012 will be a lot more draggy than a slimmer section within the possible speed range and it will be easier for the bottom of the hull and for grounding but I do not know how you plan construction. Hope you enjoy the time of pondering around.