Kicker ( vang) systems

Following on from the thread on the continuous kicker system. I started thinking about kicker systems.  Many nowadays are a cascade with an additional set of purchases to give the final power.  Is there any reason why they should be in this order? -  as if you have them the other way round you can have a very thin spectra braid on the purchase and a thicker 2:1 cascade for the end that you have to pull.  As the thin rope goes around the blocks it has low friction and thus is more efficient, ( the thicker rope only has to go round two blocks).  I have done this and it works well.  Why doesn't anybody else do it, have I missed something ??

It probably is to do with the amount of rope you have to pull on to tension the kicker. If you were to have a 2:1 system as your final purchase you can only pull on a short amount of rope before you are block to block, therefore not giving you a wide enough range.

I hope this somehow makes sense

I've done this in lasers and in Fevas and there never seems to be an issue with the travel ( in fact it may be that it gives you more travel).

Also thinner rope does run easier round blocks - think what would happen if you had 10mm. diam rope going round the purchase system compared to whipping twine, ( OK the whipping twine would break - but you get the idea)

In theory you can do this in any way you like.

As previously stated, having the multi purchase at the bottom gives the most adjustment in the system - in a lot of boats that alone will be critical - if you have a 24:1 kicker having a 2:1 as the last element will mean that the usable throw of the system is unlikely to much more than 4cm - certainly not enough for my boat anyway.

Another justification for doing it the traditional way is that you use the minimum number of the stronger (and higher loaded and HEAVIER and MORE EXPENSIVE) blocks. In the traditional case there is a single block on the boom - strong, probably plain bearing (low line speed, high static load). The next cascade block only needs to be half the strength so is potentially lighter, and so on. If you add a final purchase this can use the lightest, smoothest running blocks as they are under minimum load and they will be cheaper than putting the purchase at the top where the loads are highest.

Quite right that the thinner the rope the less the friction, the bigger the diameter of the sheave the less the friction.

I can't see any justification  for the claim that doing it the other way up might give more throw though...




Edited by BigFatStan

With most boats you would not get enough travel on the final cascade ...