drLaser Cunningham - REVISED

drLaser

drLaser

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Following Interpretation 5, a simple revision that makes the no-friction drLaser Cunningham legal again is now made available on the drLaser website. (I waited, but none of the past users came up with a better way to legalize it than this.)

Now ILCA can issue a new rule change, calling it an "interpretation" again. Before ISAF itself mingles in our affairs.

Regards,

SG
 
Shevy,

I agree that this is an ingenious interpretation of the interpreted rules!

I have a couple of questions/observations though:-

1. At the junction of the grey/orange line do you intend to tie it off to the top of say the vang fitting so the line wont move at that point? If that is the case I dont think that you can claim that it is moving through the cunningham eye because the green 5 mm spectron line prevents that. That then, in my view, calls the arrangement's legality in to question.

2. If however, at the grey/orange point, the line were to pass through a block, the tension in the grey line would pass through to the orange line and the orange line would then move through the cunningham eye and thus legality would be restored. Of course it would no longer be a 6:1 sytem but a 9:1 system. Was this your intention? Personally I prefer more mechanical advantage than 6:1 to reduce actuation loads.
 
Clive!

Thanks for noting the problem in the figure.

That's what happens when you rig it in the marina and come home to draw it from memory. And when the picture in your mind is wrong, the rest follows.

No, my line IS moving. But it's neither 1 nor 2 above.

It's just that the slack (orange) part is deadended (NOT ON THE LOOP BLOCK BUT) on the block at the top of the cascade (my H348) - which, when hauling in, moves down and therefore pulls the orange line through the grommet. When letting the line out, the grommet moves up and pulls the orange line through grommet again!

A thousand apologies.

I will correct the drLaser images and text ASAP.

Shevy
 
Corrections are now done in the drLaser article.

Note, Clive, that the same "ingenious interpretation" can be used to get around Interpretation 6 for the outhaul system!!!

I'm still receiving alternative outhaul designs from fellow sailors (all using the fairlead block concept). So, before publishing, I'm waiting to see if anything better than what I have currently will be suggested.

SG
 
Shevy,

OK, that makes good sense. I am still looking for a low friction system at greater than 6:1 for lower actuation loads and greater precision. I will see what I can come up with as a variation on your system.

Regards,

Clive.
 
Not much of a redesign is necessary if you are willing to have BOTH sides of the "tack loop" line lead from One side of (instead of around) the boom. Then, with a short tack loop, you can even replicate a 10:1 (like the Harken rig) still using a no-friction tack loop.

For years now, many sailors have been leading their (old rigging) cunnningham lines all on one side of their booms. If you are willing to do that, it's no problem. I just don't like the assymetry this practice creates in port versus starboard tacks upwind.

Shevy
 
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