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Re: back to trapeze [Re: brucat] #282295
03/28/16 05:05 PM
03/28/16 05:05 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
I did some reasearch and the Allen Keyball system linked above retails for about $130 according to Sail magazine's Pittman innovation award. LINK. That's a bit cheaper than I had expected it just by looking at it. However, looking around, I found it available for sale at an Australian outfit for about $175 USD (currency converted). That's a spreader bar and two of the post and ball devices.

I also found some complaints about the old Bethwaite system and this new system...though Allen seems to have been working to resolve the latest complaint there was a failure of the ball resulting in the sailor making a splash. The new Allen system uses an aluminum ball that is swaged onto a short steel cable that is then swaged to the straight aluminum handle. This gives it the needed flexibility to not jam in "U" shaped receiver if you twist your body like many of us do on the trapeze to face more forward. I would be concerned about that system not eventually setting a wonky bend into the wire leading to reliability issues.

Which leads me to one of the complaints with the older Bethwaite system...Apparently, the ball would sometimes jam as a result of this twisting and the carbon plate that formed the spreader bar could be really harsh on the straps leading to some failures. The system would wear and have to be replaced semi-regularly.

There are also complaints about the system being too easy to dislodge from the receiver but it also sounds like a lot of these dinghy guys are just running a bunji straight from the ball device to the boat and not up through the trapeze system like we normally do on the cats.




From Sailing Anarchy Forum
Originally Posted by BenG on Sailing Anarchy
After the death of an 18' sailor in our club, just over a year ago, some of us looked into alternative trapeze mechs that might be safer. The Bethwaite key - ball system seemed interesting but were apparently unavailable, and the revised version by Allen hadn't yet been released.

I looked into the key-ball type system and realised that it's not nearly as simple as what it seems on the surface - the keyhole geometry would need to be carefully designed and sized, so as not to get a 'false' hook up, yet release easily. The ball would have to be flexible so it doesn't jam if you roll to one side in the harness, but stiff enough to engage and disengage reliably. The ball has to be somewhat protected by a stick so it doesn't pop your eyeball out every tack.
These are some of the more obvious things. I realised to do something better (than hook and loop) would require major effort.
As said the height of the elastic should be adjusted to suit your own trapezing style, whether you want it to spring out when unloaded or remain hooked in until you're seated. The ball on a longer stick could be a handy variation for one-arm hookups, some classes prefer this.

I think it's a good idea. I hope everyone persists in trialling and evolving the idea to perfection.


Jake Kohl
-- Have You Seen This? --
Re: back to trapeze [Re: waterbug_wpb] #282296
03/28/16 05:23 PM
03/28/16 05:23 PM
Joined: Jun 2001
Posts: 733
Home is where the harness is.....
Will_R Offline
old hand
Will_R  Offline
old hand

Joined: Jun 2001
Posts: 733
Home is where the harness is.....
A couple of points:
- The keyhole spreader bar is only 10" wide, stock width for a Magic Marine spreader for L or XL harnesses is 12". The narrower spreader bar isn't nearly as comfortable for long days on the wire.

- Keyhole spreader bar is ~$150 each and you have to buy the ball attachments for $30/pair; add shipping, you're up to ~$200 on top of the cost of your already expensive harness.

- Now figure that the crew and skipper need to be able to trade wires when going downwind; double the cost from above.

- If you sail on multiple boats/multiple skippers/crews; now you get to change spreader bars depending on the boat and get used to the slight change that each system requires in how you hook up and release. The setup that we use is minimalist, but I can use it blindfolded; missing and falling off sucks.

- Keyhole system doesn't fit all harnesses; e.g. Zhik T2, Magic Marine Viper.

I'll admit, the current Magic Marine quick release spreader bar that I have doesn't instill a lot of confidence and I need to order a new non-release one. I've seen people get separated from their boats due to a failure in their spreader bar and/or trap ring; one of them caused a significant hand injury. I'm more worried about having a failure, taking a swim and getting separated from the boat than I am getting tangled up.

Regardless of all this; number one, YOU and you alone are responsible for your own safety. Therefore, each person has to decide where the greatest risk is and how best to mitigate it if they so choose. Personally, I prefer something that I know won't fail; as such, I have to be more careful in other areas (not putting hole in boat with hook and clearing hook if/when capsize occurs).

Last edited by Will_R; 03/28/16 05:28 PM.
Re: back to trapeze [Re: waterbug_wpb] #282300
03/28/16 08:12 PM
03/28/16 08:12 PM
Joined: Aug 2007
Posts: 3,969
B
brucat Offline
Carpal Tunnel
brucat  Offline
Carpal Tunnel
B

Joined: Aug 2007
Posts: 3,969
Some good points Will. Thanks for the additional info, Jake.

The new Allen design looks like it has enough mass to dislodge some teeth?

I personally ignore things like cost, width and strap config at this point. The market will get those items sorted over time.

Mike

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