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Kicker load on an Ent

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Post Options Post Options   Quote Eisvogel Quote  Post ReplyReply Direct Link To This Post Topic: Kicker load on an Ent
    Posted: 28 Mar 19 at 11:09am
I want to attach the kicker on my Ent to the boom with a snap shackle, so I can take it off easily during launching, as it fouls the centreboard and has already sheared it off twice (don't ask).

What is the maximum load that the shackle should be able to withstand? The one I'm looking at currently comes in three sizes, with loads of between 1000kg to 3000kg.

I'd never thought of it in that way, but I assume that there can potentially be quite a lot of pressure, and I wouldn't want the shackle to break just at the wrong moment. Would the 1000kg one be big enough?
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 11:23am
What is the purchase on the kicker? If it's 8:1, you can probably pull 100kg so that's approaching 800kg after friction losses. The 1000kg one will probably be rated as SWL so actual max load will be at least double. I think that might get exceeded in a high wind gybe so I'd be inclined to go for the 2000kg one.

However, I don't recall either of my Ents kickers fouling the CB head? Fittings are pretty strictly controlled in the Ent so are the kicker attachments in the correct places?

Also it will be easy enough to reattach the kicker when the wind is light/moderate but in a blow it might be difficult on the water so a kicker that can be attached before launching might be a better choice if it can done.


Edited by Sam.Spoons - 28 Mar 19 at 11:24am
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Post Options Post Options   Quote ttc546 Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 11:39am
Hmmmm...I can see some smacked heads while launching in a breeze with the boom flailing around with no kicker to keep it vaguely under control.....
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 11:40am
The shock loads can be far higher than you can pull. However, I'd think a couple of tonnes would be plenty.
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Post Options Post Options   Quote Eisvogel Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 1:11pm
I think the kicker is 16:1, so pulling 60kg would get me almost to 1000kg if I worked that out correctly.

The grip at the front of the centreboard is just in the wrong place for the kicker; it's fine once the board is down even a little bit. I had problems on the shore with the boat still on the trolley with the wind gusting and shifty; the boom moved across, kicker got stuck on the handle, and off broke the top part (the bit that was out of the case at the top).

Rupert: so you think the 2000kg should suffice?
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 2:07pm
The weakest point in an older Ent kicker system is probably the lower fixing. Not sure how your's is fixed but mine were both screwed into the hog (early wooden boats, I can't remember but I imagine the kicker was no more than 4:1 TBH).

Edited by Sam.Spoons - 28 Mar 19 at 2:08pm
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Post Options Post Options   Quote Granite Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 2:16pm
I think that 1000kg will be more than enough. Sure there is a lot of purchase, but do you think you could feasibly lift 60kg, equivalent to a small adult with one hand using 4mm control line? Also think about the strength of other components in the system. Look at the final line strength, or final block type they will give you a good steer for strength of the system.


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Post Options Post Options   Quote ChrisJ Quote  Post ReplyReply Direct Link To This Post Posted: 01 Apr 19 at 1:06pm
Enterprise 20361: When new, that had the lower kicker attachment as a U-bolt, bolted through the hull, with a backing plate underneath. It would take a lot of rotten wood and close to a complete boat failure for that to pull out! 

And if the boom is still the original, then the fitting on the boom could easily be in the wrong place. When new, it had a complex highfield lever system on the boom for the top of the kicker, to allow a coarse as well as a fine adjustment on the kicker lever. I suspect this was all replaced with a proper cascade system years ago!


Edited by ChrisJ - 01 Apr 19 at 1:08pm
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 01 Apr 19 at 3:36pm
I've bent 1 tonne ones before,(they distort enough that they no longer meet) but never a 2 tonne one, and the pressures cannot be that different between Ents and Minisails in the great scheme of things. My other boats have always used either closed shackles or keys.

Moving the boom take off point forward would reduce leverage, but mostly take out the forward component. It would create more crew room, too. But the big draw back it it shortens the length of travel for the last purchase. Do Ents have strict rules on the length of handle the centreboard needs?
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 01 Apr 19 at 5:09pm
Originally posted by Granite

I think that 1000kg will be more than enough. Sure there is a lot of purchase, but do you think you could feasibly lift 60kg, equivalent to a small adult with one hand using 4mm control line? Also think about the strength of other components in the system. Look at the final line strength, or final block type they will give you a good steer for strength of the system.



Good point about the block types, they will indeed be the weakest link (most likely) but I reckon I could pull 60 kg onto my kicker line so, with a 16:1 cascade 960kg less friction losses (which will be a fair percentage) but it's the additional shock loads in a windy gybe that will be the issue and they could easily be double or triple the static load.
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