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Trapeze wire length

Posted By: Eric_J

Trapeze wire length - 02/28/19 07:03 AM

Hi,

I wonder if anyone knows what is the length of the trapeze wires on the F18.
What Dyneema rope (diameter and spec) is most recommended for this task?

Thanks,
Posted By: samc99us

Re: Trapeze wire length - 02/28/19 03:57 PM

It depends on your particular boat; hounds are not in the same location.

For the Nacra Infusion the hound is in the same location as the Nacra 17: http://nacra17.org/class-info/rigging-part-list/

You have a few options on material:

1) 2.5mm Marlow D2 Max SK99
2) 3mm SK78 (any brand)
3) For a durable set you can use a line with a dyneema chafe sleeve: http://www.apsltd.com/new-england-ropes-sts-wr2-dyneema-line.html

In 3mm that WR2 is a very nice and super durable trapeze line.

I generally float my ends so I have a few inches of travel adjustment at the base to get the handle right where I want it.
Posted By: Eric_J

Re: Trapeze wire length - 03/04/19 01:53 PM

Thanks for your valuable reply.

Eric
Posted By: rehmbo

Re: Trapeze wire length - 03/04/19 04:09 PM

I'm currently using 2.75mm Samson AS78. 3mm was too thick to get the buried splice through the Ronstan handle. As Sam mentioned, I use a 4cm piece of cover to protect the top loop on the shackle.

As for trapeze length, for my C2 I'm at 6.40m 'pull to pull' for both crew and skipper (there is loop at top and thimble at bottom that sets into the bottom of the trap handle).

There is some fudge factor since this length simply determines the comfort level of the handle position. It's the combination of this and your shorter trapeze ring take-up line that determines your final trapeze height. If you have adjustable traps, then you have almost complete freedom.

Also, something from the 'don't ask me how I know' department: It's strongly advisable to run a bungee from side-stay to side-stay across the front of the mast - at about the level of the spreaders. I've had saggy trap lines get hooked by the spreader arm during a tack. The result was a major shock load that resulted in a broken trap line at the top shackle. The only time I've ever had such an issue. I usually store the boat mast-up in the summer and replace them every 2-3 seasons. The only failure I had had nothing to do with UV degradation.
Posted By: Eric_J

Re: Trapeze wire length - 03/05/19 06:49 AM

Thanks Jeff
Posted By: samc99us

Re: Trapeze wire length - 03/05/19 01:54 PM

Interesting Jeff. Luke and I could never figure out what that bungee actually did; well it's saved a kite drop for me once or twice from ending up in the spreaders. The problem you describe we aren't faced with because we run bungee up fuckers in the dyneema trap lines themselves above the handles so the system is kept under constant tension.
Posted By: rehmbo

Re: Trapeze wire length - 03/18/19 02:17 AM

Funny you mention that - the first time I heard of the bungee was for the spinnaker, and I had never seen an instance where it was needed and never had used it. But then I learned...

In theory, my trap handles have constant tension too, but a combination of lowering them a bit and re-using some older bungee resulted in the sag. As mentioned above they got caught by the spreader during the tack. When the crew went out on the wire, the load was enough to pull the mast rotation back a bit and suddenly release the captured tack line resulting in the shock load as the crew 'fell' a few inches. This ruined a good regatta for me a couple summers ago as my crew went for a swim which is decidedly not fast. Tried to do an on-the-course repair, but spectra/dyneema doesn't like knots (too slippery) resulting in a second swim.

Now I try to keep a bit more tension on them, run the above-mentioned bungee, and have a reserve trap line setup on the boat in case the poop hits the air-mover.
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