MERLIN ROCKET FORUM

Topic : Twin poles

This may seem a silly question but does the pole downhaul go into a hole at the bottom of the pole (outboard end)pass through then tie to the ring? If this is so is there a bungee system somewhere to keep it all tight? I have no other boats to look at and I cant make it out by looking at photos. Also how long can the poles be on my old boat, 2914. The pole I have seems rather short, and bloody heavy! Thanks, in advance.


Posted: 17/04/2009 08:05:19
By: John Saunders
Sounds about right!

IIRC, there's an uphaul connected to the end of the pole, there's a ring attached to the end of the downhaul (the sheet/guy is threaded through the ring). The downhaul passes through the end of the pole, down through the hole to the fairlead through the foredeck.
Below the foredeck is the pulley system to tighten it (on mine, both downhauls are connected to the same downhaul and there is an elastic bungee to release the tension (i.e. to make sure that the downhaul does release).
There's no elastic to keep everything tidy... (usually the spinnaker sheet/guy drape over the sides of the fordeck - it's visible in many photos!).
Hope that helps,

Colin (3387)


Posted: 17/04/2009 08:32:17
By: Colin
I've got 2 photos that I think make the outboard end of the pole fairly clear.

Pole length is currently 2.3m (for a 'new rules' kite) but you might have an old 6ft pole perhaps, which is fine with an older kite.

http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/rigging_guide/3489&file=3489_pole_end_out.jpg

Posted: 17/04/2009 09:36:24
By: Mags
Where do you live? There might be a nearby club where you can visit a local Merlin to have a nose at the system.

http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/rigging_guide/3594&file=3594_pole_outboard_end.jpg

Posted: 17/04/2009 09:36:58
By: Mags
Longer poles don't seem to be a problem whatever size spinny you have, there is little point in going for anything shorter.  Carbon poles are durable and easier to handle if you can bear the expense.  Otherwise 28mm ext diam ally tube is adequate, the load is all in compression as long as the ring is snug into the end of the pole.  You need very low stretch stuff on the downhauls with a 2:1 to a good cleat, loads are very high on a tight reach.  It can be awkward to install this part of the system in older boats and there are a number of alternatives for the siting of the cleat, should be accessible for helm to operate, and you need to have enough throw in the system to be able to get the pole on and off easily with mast rake on, which alters the pole height as the whole rig comes back.


Posted: 17/04/2009 12:36:56
By: Andrew M
P.S.  There is a block on a bit of shockcord below the foredeck on my boat, the downhauls go through this just after passing through the deck bush and it pulls in enough slack to stop the sheets falling in the water.


Posted: 17/04/2009 12:40:57
By: Andrew M
I think you'd want 32mm (Inch and a half) alloy tube for long poles unless it's a very high grade alloy (in which case just use carbon!). All the 28mm ones i've seen have bent enormously after use in strong winds. Also you'll want the better quality pole ends that are designed for the thicker tube. The 25mm ends are not up to job and tend to cause holes in laminate mainsails and a bluey-red tinge to the air afterwards.

Anodising is not really necessery though so you may be able to make a saving there, though it may only be pennies. Even using 32mm tube you should be able to knock up a pair of alloy poles for about £85 at most.


Posted: 19/04/2009 09:30:56
By: Chris M
I did a bit of a takeaway system on White Whale under the foredeck after looking at some modern boats.  The takeaway system(see above shockcord remark) seems to be absolutely key in getting it all to work slickly.  Have a look under someones foredeck on a new boat.  Then getting the lengths right for the downhaul is key to perfecting it.

Unless you're claiming unemployment benefit and going hungry so your kids can eat, for heavens sake get carbon poles. buy 'em made up from speed or P&B or whoever......


Posted: 19/04/2009 13:44:44
By: Jon
Well, I have to go for twin poles now as I dropped the tin single over the side this afternoon, and it sank! 35 years old and I am the first person clumsy enough to loose it! Thank you for your advice Jon but you do not know me. I never buy anything new/ready made/expensive. There is always a way!


Posted: 19/04/2009 19:10:10
By: John Saunders
John,

I am the same. I too never buy anything new/ready made if it's for sailing unless it is a real must/last resort. To part with best part of £230 for what is in effect 2 pieces of 1" carbon tube 2.3m long to me seems like daylight robbery! Make some up from ally, just as good. Buying carbon because that's what "everyone" has really isnt going to make your boat go any faster, trust me!


Posted: 19/04/2009 20:02:18
By: :-)
The problems I found buying carbon tube were 1) Length as noone seemed to want to supply more than 2m lengths cheaply and 2) Actually fining the correct stuff as 32mm i/d with the correct wall thickness (3mm?) seems to be (or at least was) like hen's teeth. I ended up buying 2 made up ones!! By the time you've bought the correct material and fittings from speeds or P&B and put it together yourself you may as well pay them the extra £20 to do it for you.

Sourcing carbon is a little better now, carbonolgy probably have the right stuff but they aren't all that cheap either (£119 for a 2.5m length exc fittings). I don't know of another source that will supply more than a 2m length.

Ally is differant matter and is easy to source. It clatters and clangs but it will do the job. Personally i wouldn't bother with carbon poles unless you're doing the boom as well. You don't save much weight in the poles and the length is the issue anyway not the material.


Posted: 19/04/2009 20:22:34
By: Chris M
i've currently got a non adjustable height system on the pole-up. Any idea how much string i'll need to rig twin pole up and down's? There is a convieniently placed cleat on the mast just above deck level


Posted: 20/04/2009 14:07:35
By: Tim 3435 Perestroika
Our last spinny pole came from Beaulieu boat jumble (this Sunday, 26th by the way) but if you go for single pole, have a pull cord between the two ends then the uphaul/downhaul join together in a loop around the pole but inside the string. That way it can't fall overboard and can be stowed along the boom. A piece of drainpipe rivetted onto the boom for supporting the pole rear end makes a good substitute for the expensive spinnaker pole loops from the chandlers.


Posted: 20/04/2009 14:13:58
By: Pat2121
Tim,

The spinnaker can not be higher than 4.22 mtrs above the black band. The Black band can not be higher than 0.73mtrs above the sheer line.

As your cleat is above the deck => above the sheer line, you will need approx 6mtrs of 4mm to get up to the sheeve block and out to give you adjustment. And then 2 bits of thinner 2mm about 4 mtrs long to get back down. Add some saftey to these numbers.

Buy strong, non stretchy rope, like Excel Racing, I tried cheap string once. I wasn't a good idea.


Posted: 20/04/2009 15:16:37
By: AlanF
p.s. the sheeve for the strings are always lower than the sheeve for the spinnaker halyard, but on an older mast set up originally for shorter poles the sheeve is lower.  Don't over trim yourlines till you are happy with the geometry in practice.  (if you have long poles on an old mast you probably have shockcord tied into the uphauls to lift the poles to boom height when inboard)


Posted: 20/04/2009 15:22:54
By: AlanF
Like this

http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/rigging_guide/3594&file=3594_pole_uphaul_elastic.jpg

Posted: 20/04/2009 15:24:29
By: AlanF
Or you can do this

http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/rigging_guide/spinny_pole&file=uphaul_top.jpg

Posted: 20/04/2009 15:26:28
By: AlanF
John

The helm benefits from carbon poles as they do not hurt a great deal when the crew throws them back in your face! Worth the money!


Posted: 20/04/2009 16:30:49
By: RichardT
Dunno about that: I've caused my helm a few shiners from doing just that (with carbon poles). The only obvious answer to that one is in Dan's spinnaker drill paper: the crew yells "POLE" before unclipping and the helm ducks...


Posted: 20/04/2009 16:48:07
By: Nick
I find flying elbows are more of a problem personally. I think it depends on where you are in the boat and the system used.

Older boats used to use elastic threaded through the boom so that it pulled the poles back with some force. This was (In my opinion at least) downright dangerous and asking for trouble. The other popular system used wire strops along the boom which is a little better, but still had elastic that went from the pole to the wire strop which (depending on tension, but it had to be quite tight or the poles drooped) could still give the pole quite a kick back, but was more of a problem for the crew than the helm apart from the bloodstains.

The current standard with the poles running down elastic either side of the mast seems pretty friendly to me. The pole doesn't need to be thrown back, just given enough of a nudge to clear the mainsheet. Beacuse it's not really under load it doesn't fly back out of control. It's cheap and easy to make up as well.


Posted: 20/04/2009 17:27:29
By: Chris M
Ah ha!! we are on the way, alli tube from local scrapyard �3.00 enough for both poles but it is in 2' sections that slot together, bit of 'poxy and some pop rivets, twin poles by weekend!


Posted: 20/04/2009 20:10:29
By: John Saunders
You're rivetting together 2ft sections.....heck, you're even more cheapskate than me! I thought I was bad...


Posted: 20/04/2009 21:53:13
By: Mags
and they will be back in the scrap yard in 1ft 8 inch sections by the following weekend


Posted: 20/04/2009 21:56:17
By: .
.

No they won't.


Posted: 20/04/2009 22:08:54
By: Richard Battey
I'm not sure i'd trust that either, but time will be judge!


Posted: 20/04/2009 22:13:08
By: Chris M
Oh ye of little faith!! I shall open a book on it. Who will give me 10 to 1 on?


Posted: 20/04/2009 22:32:18
By: John Saunders
Come on, the Merlin is a baurtiful boat - don't spoil her looks with a messy pole like that! At least wind some tape round the hide the joins, and make it look like the tape is for grip?


Posted: 21/04/2009 09:25:59
By: Mags
Don't worry, If it works I will spend some money! If I knew how to send a link I would post a photo.


Posted: 21/04/2009 11:07:39
By: John Saunders
Whatever you do? Do not try and use the Bungee system to relocate the pole of the mast and down the boom? It Hurts??????? Conk broken 4 second time - First Rugby - That`s understable!!! Cheers AAAALLLEEEZZZZ!!!!!!!!!!!!


Posted: 22/04/2009 00:19:54
By: AAAAALLLLLLLLLLLLLEEEEEEEEEEEEEZZZZZZZ
Just rap it in fake carbon tape it will look fine


Posted: 22/04/2009 03:50:10
By: Pabs
I installed a "flying" pole on a Javelin I owned a few years ago made out of half an ally windsurfer mast, heavy. You pulled a rope and it shot out just jamming against the mast, cleat the rope and it stayed out, uncleat and a bungee shot it back on an unpredictable trajectory. Oh we did laugh, like Russian roulette, blood on the water! 

Thank you for the comment from our far eastern correspondent. (Pabs)


Posted: 22/04/2009 07:34:15
By: John Saunders

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