keeping it up...

[Steve_scott]

Hi all

I'm having trouble keeping the main sail fully hoisted on koko.  I've just put on a new halyard (4mm Marlow 8 plait pre-stretched) but its still dropping whilst I'm out on the water.  I've also added a 2:1 purchase before the halyard cleat to try to keep the tension up but somehow the sail is still dropping?!  I don't think its slipping in the cleats... so maybe my pre-stretched rope isn't pre-stretched enough?

Any ideas or should I resort to ditching the halyard and just tying off at the mast head like the more modern boats? 

Any ideas welcome...

[roland_trim]

One hypothesis is that the plaits in a plaited rope  want to make a "square diamond" shape when unloaded and an "elongated diamond" shape when under load. The fibers want to move, but friction between plaits stop this happening.
Over a short period of time friction is overcome and the plaits adopt the straighter tighter formation, resulting in the rope getting longer (and a bit thinner). When you unload it they "spring" back. So every-time you use the halyard it grows longer after you load it and shrinks back when unloaded.

Search for Will Lee's posts on this forum for a better explanation and some tests.

It may be worth accepting the halyard will grow and putting a "catcher and knot" system in at the top, this way the halyard is only under load when raising the sail?
Alternatively, maybe a second setting to move to after the first two tacks of any outing?

[phil_kirk]

I'm afraid that pre stretched isn't pre stretched enough for this application.  You need a dynema rope halyard to stop this from hapening.  Over time the aluminium style jamming cleats will wear and cause the rope to slip. 

Most of the modern cherubs don't have halyards at all but have to be rolled over to rig.  if you have an area of grass at your club this is possible and allows you to tie the sail to the top of the mast.  This is a bit more time consuming and inconvenient than being able to pull the sail up but may be a temporary fix for now.

[Graham Bridle]

I used to hold RV's 05 main up with a halyard very successfully with 5mm dyneema, hooked onto a 2:1 at the bottom and the tail into two cam cleats, works fine but did cause people to question my sexuality.

For a boat that needs care like KKP I wouldn't recommend rolling, you'll damage the gunwales no matter how hard you try not to, and probably get a load of duck s**t all over your sails.

You're on the right lines, just need to wedge out on some more expensive rope.

[Phil Alderson]

I use Dynema 2:1 at the head of the mast, it is spliced into a loop at the bottom, which I hook onto one of the hook racks, like people used to do with wire haliards.
I have not had any problems with it slipping, and use cheap rope for the tail.

[Steve_scott]

Fair play - I decided on the 8 plait because it said it was good for halyards... and it was pretty much replacing like for like.  I'll try some dynema but can anyone help explain the knot and catcher system?  Presumably this means I can raise it on the halyard but I have to roll it over to release the catcher; or will it release when I let the tension off at the bottom of the mast?

I've been caught out on the beach before trying to drop the main in windy conditions just to make her stable enough to get her onto the trolly and out of the water.... when under power she's fine but she's like a bucking bronco on the beach so I'd like a reliable, easy to use system that stays up... but will also drop in a hurry when needed.

[Torchy]

To stop the bucking bronco stuff many use a quick release system to attach to the trolley. Will show you at the Inlands....you are coming to the Inlands aren't you?   

[Steve_scott]

I'll certainly try to make it down but it won't be with koko - I'm without a tow hitch and a reliable crew!

[JimC]

I always had a hook at the top of the mast and two rope loops on the sail - two, because its irritating if one breaks otherwise. Given space and an adult crew I always found rolling the boat over to be a better solution than halyards - I stopped using halyards in about 1978! Few Cherubs built since the late 70s would have had halyards when new: rather more will have had halyards retrofitted by new owners, often to be removed again later. The problem with halyards, even if the compression load isn't a problem, is that the sail will always drop a bit with mast bend, and there's nothing you can do about it.
Now I sail a singlehander rolling the boat isn't really a choice, and after much irritation and chewed expensive ropes I came to the conclusion that the only good solution is a halyard lock. However there is not IMO anything suitable on the market, so I had to make one. Its not perfect, but so far the best alternative. It would be better if I had the skill/equipment to fabricate stainless steel fittings.

[andy_peters]

Two things we do with our halyard

1. when new put it through the washing machine which makes it more grippy in clam cleats
2.  Before every sail put up the main then wang the downhaul on as tight as you can.  Let it off cpompletely and then pull the main up - you usually get an inch or more halyard on that way.  Result is the sail usually stays at the top

[Steve_scott]

Andy.... like the taking out any stretch with the downhaul and re-tightening... Will give it a go this week.

I've also just test fitted the new kicker assembly and it looks soooo much neater.  I'm currently just running a single cascade as waiting on delivery of the second high load block but even now its got loads more power so may not need the second cascade after all.  I'm also running 4mm control line on the cascade and I need to replace that with some dynema that I can splice in neatly and not worry about the loads. 

Kite sock is work in progress.... I have a working solution but it isnt pretty yet....

Getting there.....