Rotating masts and dangly poles

[Jimbo41]

Just wondering if you could still use a dangly pole with a rotating mast... No idea of geometry, see.... ??)

Jim N3130 and N3470 and a large box of Viagra powder (for N12 pimping purposes only! - sorry just a little larger than life today - all John Murrell's fault - he pointed out the 12' Skiff link!)

[THG]

Jim - as I recall there was an earlier thread on the AUS NS14s - they have rotating masts and someone was looking at adding a dangly - not sure if it worked - windage was a concern.  Maybe they have some posts on their own site - google NS14.

Kean

[Jon_P]

The whole idea of a rotating mast is to reduce the seperation around the mast and increase the lift available.  If you then stick a pole down the side of the mast it's kind of a waste in adding the complexity of the rotating mast.  

Jon

[Jimbo42]

[hairy dog]

There's no complexityto a rotating mast.  It sits on a pin (at deck level) and (by clever use of string and a lever) rotates with the boom.  By adjusting the string between the boom and mast the angle of the mast relative to the (apparent) wind can be altered.  I think most small cats (not Chesire variety) use this system.

Dangly poles are frowned upon by the NS14 class due to the windage but boom launched ones are quite common and don't seem to adversely affect the mast rotation.

[Mikey C]

I'm constantly surpised that no one has done a hoisting dangly pole that is stowed on the boom for upwind, and raised for downwind...

[Jimbo41]

Mikey! Don't you mean stowed on the mast rather than boom? How would the boom one be "raised"? Don't some people recommend the use of velcro for our mast launched design, since it stops them flapping around?

Jim  

[THG]

I can see what Mikey is getting at, some sort of system maybe a bit like the Merlins twin spinny pole system - these store on the boom (so should be less windage (or even less noise / mast damage) - then some how you need to raise these up into a vertical / tension as they are currently - could be interesing to get to work - maybe even a double pole system could be used???

Kean

[rick perkins]

If anyone has a system for that please share it as that pole drives me nuts flapping around upwind ...

[John Meadowcroft]

Rick
I suffer from a similar frustration from time to time.  To stop it flapping around, just pull the pole line taught so that it goes to the clew of the jib.  no more flapping around.  I think the flapping is only really an issue in a chop as otherwise the pole just deflects in the slot at a pretty constant angle.  As noted elsewhere the pole in the slot feels as though it should provide drag and slow you.  (This may be perceived to be a bigger issue in an NS14 which has a substantially more efficient rig than a 12)  I imagine that whatever the negative drag effect is, it is offset pretty quickly by ease of use factor.  Key thing is being able to get the jib working efficiently as quickly as possible when you get going downwind.  Get on the plane quickly and then bugger off.  A popular thread on this forum is asking the question which hull planes earliest.  A more pertinent question is possibly what do I need to do to make sure I get my boat planing at the earliest opportunity!.....
meds

[Mikey C]

Eat less Christmas dinner!

[Simon Nelson (Guest)]

As an outside observer, I have been suprised that nobody has tackled this whole "dangly pole" issue yet. It seems to me to be crazy to mess up one of the most important areas, the slot. In addition, the closer the pole is to the mast, the worse the problem.

One thing that is critical is, as Meds says, ease of use. It was for exactly that reason that I put the first self launching jibstick on a 12. The problem with the current system is that in addition to poor aerodynamics, it needs constantly playing with. Great if you have a top, experienced crew but not so good if you haven't.

I have discussed lots of ideas but not having a 12 or the time, I have done nothing. What is needed is a system that doesn't mess up the slot and doesn't need changing as your angle to the wind and amount the jib is sheeted in cahnges.

My prediction is that somebody will, one day, make a jib boom work! Adam May and I have discussed this at length and we are convinced it can be made to work. So where are the lateral thinkers?

[aus_ns14 (Guest)]

I did a dangle pole on my (now former) NS... sold it last week. Simple enough to set up - tight dyneema line down the front of the mast, internal elastic retraction line, single launching line to a swivel cleat on the bottom of the mast section. Seemed to work alright, the big trick was getting the pole length right, nothing a hacksaw and a few quick runs on a saturday morning didn't fix. I think that it had a couple of advantages - a) no chance of losing the pole over the side as that is where my last pole went before the dangle came along, b) the pole was quicker to launch, so there'd be about a 1.5 boatlength advantage on the dead downwinds on launching... instead of reaching over to the boom, passing the pole out, pulling the launching line and cleating it on the pole and then clipping it onto the mast. it'd simply be a matter of getting the jib to set to windward and then reef the launcher line, c) when reaching, the crew had 2 controls to deal with instead of 3 - instead of using the barberhaulers and jib track, the pole'd be tensioned and as it simply ran to a ronstan swivel cleat at the base of the mast, the crew'd play pole and sheet instead of barberhauler (which'd have to be changed on each gybe), sheet track and sheet. I don't think that the loss in windage was too great - it was simply some 12mm OD carbon tube, that was permanently attached to the clew of the jib, so it may have been in the jib slot slightly, but the turbulance off it was hardly anything too much to worry about. One idea I had (just in case the pole was backwinding the main badly) was to use some sailcloth and create a bit of a fairing around the pole and a tube clip on the mast, so when the pole was let off it could be clipped on to the mast and the fairings would help keep the windage down (although I didn't wind up doing this in the end as I think it'd only be a token effort at best). There are a couple boats aside from my former boat that also have the dangle pole - one belonged to a former N12 skipper (name escapes me though), another was sailed solely on a lake that was reknowned for having SFA breeze most of the time, so it might have been a slight advantage in that situation and the last one was a slightly modified tasar that had a setup whereby the pole'd hinge about the pole ring and would be pulled up vertically against the mast when not in use... not the most automatic manner of doing it, but it's horses for courses I guess.

I'm considering doing another dangle pole on my new toy (IC) and seeing if that helps the performance downwind... I think it'll simply be more of a hinderance than an advantage, but one of the joys of ICs is the open nature of the rig design... so anything is worth trying (at least once).

jon
ex ns1964

[aus_ns14 (Guest)]

I also have had a jib-boom on my 1st NS... worked fantastically until caught in a chinese gybe, and then it broke the foredeck about 30cm back from the forestay chainplate, because basically it worked by a combination of friction between the deck and the end of the pole (jn front of the pivot point) and a pair of lines that would launch the pole around to windward. A lot of lake-dwelling NS's had the jib booms (aka canberra poles after the capital city where they were used prolifically), and all of them would up with similar problems, often when the pole'd get jammed during a gybe, and as such they had since gone out of vogue on all but a couple of boats nowadays (one being an ex-nationals winning 'superboat', the other being the current aus. measurer's own creation. Ultimately, they are the way to go - but not on boats with high crowned foredecks, at least in the way the NS's had them. A boat like aardvark issues may be the go with the concave foredeck, but then the issue becomes how the pole can get controlled to hold the jib on the windward side of the boat.

[John Meadowcroft]

I think that you will find that Gavin Willis does make a jib boom work already.  He also has a jib stick too.  Idea of the boom is that he has a big jib and does not want it to get too deep when eased, so this prevents this happening.  Seems to work.  He also has high windage from high decks and knows how to get the boat planing quickly.