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.
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.
