Blocks or antal rings for kicker cascade?

MissFitz

MissFitz

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I want to make a simple cascade kicker system for my Sonata. The ones I’ve seen pics of use blocks, but it occurred to me that lots of boats seem to be replacing smaller blocks with antal rings at the moment. When I put this to a chandler, though, he said that was fine for backstays but would be no good for a kicker because the wear and tear is too high. Any thoughts?
 
Blocks are pretty cheap and reliable.
Low friction rings work well for some things, but there is a certain amount of friction involved in bending the rope through 180 degrees at such a tight radius. With rings, dinghy sailors are using very thin lines and changing them frequently.
 
Rings are good for leading lines through, but i'd suspect all of the tight turns involved in using them for a kicker would make them unsuitable for that job.
 
I am guessing that on a sonata the distance between the cabin top and the boom is quite small. This limits the power you can get on a vang. (kicker). Just look at the geometry. Mine is like that and essentially the vang is only used to limit the rise of the boom when running. It is not practical to use the vang as some boats do to adjust the shape of the main sail. I am also guessing that you have a relatively long traveller for the main sheet. The main traveller means you can get lots of down pull on the boom especially when hard on the wind.
So I would suggest that you do the vang in rings and don't expect to be able to actually pull the boom down but rather make it like an adjustable tether to stop it rising when main sheet is released. (when running) olewill
 
I've used LFRs for medium size cascades before. Works fine. Very light and unbreakable.

The trick is to run thin Dyneema 12-braid through the rings, and then splice a polyester cover for the jammer. If you try it with all polyester line there will be far too much friction, and if you try to handle bare Dyneema 12-braid, it will slip.
 
The Sonata kicker is very powerful and you (the helmsman) need to be able to easily adjust it up wind and (the crew) when reaching.

I've never used one with rings so don't know if they would work, but remember quite how much load the top block nearest the boom has to handle. When dumping the kicker and yanking it back on in a blow, it's easily a 25Kg pull that is needed. Multiply that by 16 (the power of the kicker) and you need a top block with a SWL of 400Kg.
 
SWL of 400kg is not much more than I'd use on a dinghy.
I could shave maybe 100g off the weight of my kicker by switching to low friction rings.
Cost would be similar for the lower blocks, Allen rings being about £8 and blocks maybe £12 each apart from the top one which is probably £25.
But I can't see the the PTFE coating on a ring lasting the 20 years that I think some of my kicker blocks have done so far?
A lot of small boats you want a 4x2x2 cascade, as 2x2x2x2 tends to run out of travel. With twice the sail area and several times the all up weight, you might want more than 16:1?
 
thinwater said:
I've used LFRs for medium size cascades before. Works fine. Very light and unbreakable.

The trick is to run thin Dyneema 12-braid through the rings, and then splice a polyester cover for the jammer. If you try it with all polyester line there will be far too much friction, and if you try to handle bare Dyneema 12-braid, it will slip.
Click to expand...

I found with dyneema it's very difficult to get the rope back out of the cam cleat bottom pulley block as there is no stretch in the line. Might add a short section of polyester above the blocks, see if that helps. Not that the kicker gets used much anyway.
 
lw395 said:
SWL of 400kg is not much more than I'd use on a dinghy.

A lot of small boats you want a 4x2x2 cascade . . .
Click to expand...

The 4x2x2 is standard on a Sonata and gives enough range. The hard part is getting the mast foot attachment point directly underneath the gooseneck so you don't vang-sheet. Most people give up and use the convenient eyes on the mast step which aren't ideal.

Even a SWL of 400Kg takes you to using a 3" classic block from Harken. That would be a chunky thing on a dinghy. As I was a Harken OEM, I used a 3inch Hi-load. The problem with under-specifying the block is that the 'middle' person in the crew spends a lot of time with their face and eyes very close to the kicker as they pass under the boom. Some of the crazily undersized blocks you see do break and the flying bits can be very close to face and eyes.
 
For a small boat kicker's top block, I would use something like this:
http://www.v-rigger.com/epages/es140267.sf/en_GB/?ObjectPath=/Shops/es140267/Products/A2030HL
A 30mm wire block.
600kg working load seems optimistic, but derating the break load of 800kg, it is in the ballpark.
The ones I actually use are Holt-Allen and all stainless.
I would not be surprised if the next size up might be desirable on a Sonata, but there's little point making it much stronger than the boom.

You raise a good point about getting the pivot point under the gooseneck. If it's behind, the vang will get tighter if you dump the main. With low stretch, that can do damage.
Some dinghies are extending the gooseneck to put its pivot behind that of the vang, as well as easing the outhaul a tad as the boom goes out.
ISTR my Impala had a lever kicker which worked fine, but perhaps did not allow the boom to be raised enough?
 
Motor_Sailor said:
The Sonata kicker is very powerful and you (the helmsman) need to be able to easily adjust it up wind and (the crew) when reaching.

I've never used one with rings so don't know if they would work, but remember quite how much load the top block nearest the boom has to handle. When dumping the kicker and yanking it back on in a blow, it's easily a 25Kg pull that is needed. Multiply that by 16 (the power of the kicker) and you need a top block with a SWL of 400Kg.
Click to expand...

I wonder if Motor Sailor understands what I mean by not powerful. I have in mind the actual pull down exhibited at the clew of the main sail. So while you might have a huge purchase advantage in the kicker tackle It is lost to a degree by the distance from the gooseneck the kicker attaches to the boom and by the angle the kicker arrives at the boom. If the attachment for the kicker is well out from the gooseneck you get less adverse leverage to the clew but the angle of the tackle tends more to pull the boom forward than down. I don't fancy that load on the gooseneck . However if you bring the attachment closer to the gooseneck you get more down pull at the boom attachment but you get a more adverse leverage out to the clew. So it seems 45 degree tackle to the boom is appropriate. This means the distance the boom is above the cabin top dictates how far out the from the gooseneck the kicker is attached. So ultimately how much power downward you get at the clew.
Now a dinghy with kicker attached at the base of the mast at the keel might give 1 metre height so 1 metre attachment to the gooseneck on a 2 metre boom gives real power. But in the case of a typical cabin topped keel boat in my case a 3metre boom and about .5 metre between boom and deck kicker is mou8nted about .5 metre from the gooseneck. So unless you have a large purchase on the tackle and can cope with a huge forward force on the gooseneck you just can't get much power. Hence we see on large catamarans a great curved track for the kicker so that it can get the power with little gap between cabin top and boom. To the point where I wonder if it is not just another traveller/ mainsheet.
Just on the subject. If the attachment of the kicker is directly below the swing pivot (L&R) of the gooseneck then the kicker remains the same length from boom fore and aft to boom abeam. That is the general idea. However if kicker attach as aft of in line with the gooseneck pivot you will get a tightening up as the boom goes out. That can be good to hold boom down when running but may overload the system. Generally it is not possible to mount the kicker forward (by much) of the gooseneck pivot so we can't use the opposite effect.
My apologies to Motor Sailor if my assumptions are incorrect and he understands what I am going on a about. Even more so if I have got anything wrong. olewill
 
Aside from the purchase required for the application on the Sonata I must say that I wouldn't even remotely consider an Antal ring in a kicker purchase. Simply too much friction.

And the truth is that I've replaced all of the mainsheet & kicker blocks on my cruisers to Harken or Holt ball bearing blocks to reduce friction and make them far more usable. After all, you're far more likely to adjust a control line that isn't a s*d: this means your boatspeed is likely to be higher.
 
Really interesting and useful feedback, thanks guys. Sounds like blocks are the way forward and very glad I didn’t buy the little Lewmar ones I was looking at last week, clearly way too small.

One really dumb question though - what exactly is a 4x2x2x2 system? Is it one of the ones on this page? (I was planning to copy the arrangement in the bottom left pic - but with the cleats further aft for use when short-handed - but very happy to hear about alternatives.)
http://sonata.org.uk/kicking-straps/
 
MissFitz said:
. . . Is it one of the ones on this page? . . .
Click to expand...

The one with the red rope I think is 2x2x2 and the top left with yellow is 2x2x4 (ie twice as powerful). (Those photos are quite small from a time when download speeds were slow! Time for new ones).

All it means is the top block (Harken 76mm) of the 'cascade' is a single block (with a x2 mechanical advantage), the next block down is also a single (Harken 57mm), but the bottom block is a double (with x4 mechanical advantage) (Harken 25mm).

To match this double block at the bottom, you will need three singles, one central on the mast step, and one either side that directs the lines cleanly out to the original deck organisers on each side. The 150 clam cleat is then close to the deck organiser, but the tail is quite long and goes back (crossing above the halyard) and runs through a small plastic bullseye on the rear of the cabin side just outboard and below the sheet winch.

This is so the crew can play the kicker when reaching, but the helm can reach forwards and use the kicker going up wind when they'll be the only person in the cockpit and you don't want your lardy crew bringing any of their weight inboard. (As shown in the bottom right hand picture, except I would have the jammer even further forward and the bullseye on the side towards the top rather than where Jack has shown the arrow pointing. As the caption says on the bottom left photo, running through clutches ensures it can't be adjusted from the rail and reaching is going to be quite traumatic.
 
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My 16:1 vang in dynema though antal rings finished off with a 2:1 polyesta line on the cabin top works fine on a 28m2 mainsail and although i cannot adjust it from the helm i do adjust it quite a lot and it is easy.
i did away with blocks for weight and because i had 3 vangs break in the past
i think the systen would work quite well with spinnlock deck jammers on each side and polyester 6mm lines lead through 30mm blocks on the tails of the dynema vang so one gets 2:1 trimming on the deck as well as the ratio of the cascade
 
LFRs are perfect for kickers, have one or two cascades depending on throw and then stick as much purchase as you like on the end using cheaper blocks and 8mm braid on braid or braided dyneema. This solution means you dont need expensive high load blocks since the terminal purchase will only see half or quarter of the full working load, and you dont lose throw by just using cascades. Quick and easy to build a powerful vang.

No reason not to use LFRs, wear and tear means nothing and a high load LFR is a whole lot cheaper than a high load block to go straight on the boom. Plus you can overcome the slight friction difference between LFR and a ballbearing block by adding an extra purchase on the end (e.g 5:1 instead of 4:1 on the final purchase) if you are really that bothered but in real terms you probably won't notice.
 
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