WishBone Sailing Rig

[T0x1c]

Yes, this are the flag poles we use as BASE.

Meaning you use them as mold and add UD eglass/epoxy layers?
Seems strange to use tapered poles with a stayed rig, where compression is constant along the length?

Buckling load of the lower wind mast and cross trusses is the bigger problem.

Indeed, buckling is the problem with elastic fiberglass. At least it would give some breath to the sail in gusts.
Wouldn't aluminium profiles make a better option for compression, especially with the central I flange? The aluminium profile is only the third of the cost of a traditional rigging, the rest is supply and fix of accessories, which is the same or more work with fiberglass.

 

[Ikarus34200]

The bigger load is in tension on the windward side. So no problem here

 

[brian eiland]

A-frame Masted Catamaran Molds for SALE

I'm sure this vessel reference has been posted before, but in looking thur some old postings of mine, I did not see it in these particular discussions

50 SMG Catamaran
http://www.sail-the-difference.com/DESIGN.28.0.html?&L=1

I posted this quite some time ago, and likely there are other references to this 50 SMG vessel in this subject thread,....just didn't have the time to go looking this morning.

But what did catch my attention was another posting on the forum that the molds and project are for SALE,....and at a very reseasonable price.
http://www.boatdesign.net/forums/boat-molds/smg-50-catamaran-moulds-sale-53235.html#post736712

 

[brian eiland]

Most multi capsizes I've heard of have been caused by a combination of big wind and big waves.

Your max righting moment assumes the boat is on a level sea. If you are on the face of a wave, especially one that is confuse or about to break, you may already be heeled quite a bit. Then add a gust of wind, and a breaker at the same time, and you'll wish you never thought of flying a hull.

Another danger of flying a hull is that more wind can get under the wing deck structure and gleefully assist with the capsize.

Ideally, IMHO, a multi should have a resilient rig which bends under excessive winds rather than breaking, or capsizing the boat.

I was just looking quickly back thru this subject thread, and this portion of your quote jumped out at me.

Where do you find anything resembling this?

 

[Angélique]

Ideally, IMHO, a multi should have a resilient rig which bends under excessive winds rather than breaking, or capsizing the boat.

Where do you find anything resembling this?

This Dutch Multihull broker says on this topic that Catalac uses weak sails as a fuse against capsize ---> Link

Quote:
‘‘ . . . . Van Catalacs is bekend dat bij plotselinge windvlagen, bijvoorbeeld uit een onweersfront, de zeilen uit de lijken waaien voordat het jacht kan omslaan. Een paar nieuwe zeilen is goedkoper dan een uitgebreide reddingsoperatie. . . . . ’’

Translation:
‘‘ . . . . Of Catalacs is known that in sudden gusts, for example from a thunderstorm front, the sails are blown out before the yacht capsizes. A couple of new sails is cheaper than an extensive rescue operation. . . . . ’’​

To me this "catamaran anti capsize fuse - sail blow out solution" seems to be difficult to achieve as it means that new sails are just strong enough for normal use and after a little wear they aren't strong enough for normal use any more.

 

[upchurchmr]

Angelique,

It puzzles me to no end in this age that we don't have a set-able sheet release, based on sail pressure.
Should be no need to shred the sails.

Watching AC45's capsize I again wondered why something automated wasn't available. I watched one boat round the leeward mark, come up into a tack and just sail the boat into a bow stuff and fall over the side.
At no time was either sheet thrown off. Well the jib was released when they were 60 degrees over on the side.

 

[Angélique]

It puzzles me to no end in this age that we don't have a set-able sheet release, based on sail pressure.

Should be no need to shred the sails. [ . . . . ]

That sounds a lot better as a multihull anti capsize fuse than the above mentioned sail blow out solution, so who brings it to the market ?

Or are there any objections to it ?

 

[rob denney]

That sounds a lot better as a multihull anti capsize fuse than the above mentioned sail blow out solution, so who brings it to the market ?

Or are there any objections to it ?

Bucket List https://www.youtube.com/watch?v=ttXu3pRTzs8 has such a device. There is a sketch of the device at https://au.groups.yahoo.com/neo/groups/harryproa/files under sheet release. It is tripped by heel or pitch angle, works best on wide proas with unstayed masts, but 2 of them would also work on a cat or tri in most circumstances.

 

[upchurchmr]

Rob,

I didn't see anything but an advertisement.
No sketch either - couldn't get in.

Far as i can tell its a fantasy.
If it is real why would it only work on your boats, not others?

Is it adjustable for heel angle?
How fast does it work?
Where is it put in a sheet system?

 

[rob denney]

Rob,

I didn't see anything but an advertisement.
No sketch either - couldn't get in.

Far as i can tell its a fantasy.
If it is real why would it only work on your boats, not others?

Is it adjustable for heel angle?
How fast does it work?
Where is it put in a sheet system?

You're a clever chap to know it is a fantasy before you have seen it.
Google harryproa Yahoo chat group and sign up.
As I said, it works on any boat that heels or pitches, but the wider/longer the boat, the better, to reduce the wave effects.
With unstayed masts easing the sheet when sailing downwind allows the sail to weathercock rather than hitting the shrouds, which is much more likely to prevent a pitchpole or diagonal capsize.
Easy enough to make it adjustable for heel angle, although for Bucket List it is a set and forget arrangement.
Works immediately the heel angle is reached.
On BL, it is located after the winch in a 1:1 mainsheet. The main is self vanging (wishbone boom), so the loads are all sideways and relatively low. 2 turns around the winch would be adequate in most situations. Lead the sheet from the release back around the winch in the opposite direction and there will be almost no friction to slow it down when released.

 

[brian eiland]

Automatic Sheet Release

Ganovelli concept

http://www.ganovelli-concept.fr/index.php?option=com_content&task=view&id=6&Itemid=47

To date, the ACS has been installed on several of the 60-foot trimarans participating in the Route du Rhum 2006 and in other ocean races:

 

[brian eiland]

Pfeiffer adjustable tension cam cleat

Here is a photo of another releasing cam cleat that I utilized on the centerboards aboard a Louisiane 37 cat, and on the centerboard and rudder of my Firefly trimaran design. Both worked very good.

http://www.boatdesign.net/gallery/showphoto.php/photo/4907/size/big/cat//ppuser/399

I'm pretty sure they are no longer manufactured.

I could well image a scaled up version for big sheet loads with perhaps a solenoid in control.

 

[brian eiland]

http://www.fastsailing.gr/sailing.asp?catid=4311&subid=2&pubid=1763

 

[upchurchmr]

Rob,

I'm familiar with how everything you do is wonderful and better than everyone else.

If so it seems you would want to actually show it instead of stuff it away in a site for your enthusiasts.

I'm sure I registered for your site once upon a time. I just don't care enough to go do hide and seek to find the reference. I've done that with you before.

You're a clever chap to know it is a fantasy before you have seen it.
Google harryproa Yahoo chat group and sign up.
As I said, it works on any boat that heels or pitches, but the wider/longer the boat, the better, to reduce the wave effects.
With unstayed masts easing the sheet when sailing downwind allows the sail to weathercock rather than hitting the shrouds, which is much more likely to prevent a pitchpole or diagonal capsize.
Easy enough to make it adjustable for heel angle, although for Bucket List it is a set and forget arrangement.
Works immediately the heel angle is reached.
On BL, it is located after the winch in a 1:1 mainsheet. The main is self vanging (wishbone boom), so the loads are all sideways and relatively low. 2 turns around the winch would be adequate in most situations. Lead the sheet from the release back around the winch in the opposite direction and there will be almost no friction to slow it down when released.

 

[rob denney]

Rob, I'm familiar with how everything you do is wonderful and better than everyone else.I'm sure I registered for your site once upon a time. I just don't care enough to go do hide and seek to find the reference. I've done that with you before.

You were "puzzled" about anticapsize devices, I provided an answer. Your call whether you look at it or not.

I'm happy to discuss anything I have written that you disagree with, but please be specific. On the relevant thread, please.