How long should my spinnaker pole be?

[jcpa]

Years ago, when I sailed dinghies, spinnaker poles lengths were defined by class rules, but I can't find any official length for my pre-owned, 1985-vintage Kelt 8.5. It currently has a Selden telescopic pole, with click stops at 3m (labelled spinnaker), 3.6m (labelled Genoa), and 4.5m (unlabelled), but I don't think this was the original pole for the boat - the other spars are by Z-Spar. When flying my new spinnaker on a shy reach, we set the pole at the 3.6m length, and the spinnaker set rather nicely. However, the up/downhaul connections were mid pole, and the forces were too large; the smaller diameter inner pole (at the front) bent badly. The pole was trashed!

In retrospect, it would have been better to connect the up/downhaul to the end of the pole, but then we should probably also have stuck to the labelled setting.

Fortunately, Selden have supplied me with a new inner pole extrusion - I just need to fix the various fittings to it and my pole should be restored. However, the extrusion is considerably longer than the original, and I could maybe use some of this extra length!

The sailmaker who made my spinnaker says the pole would usually be the same length as the J measurement (3.14m for a Kelt 8.5), so the spinnaker tack would be approximately above the stemhead on a shy reach. In that case, I could cut my new inner extrusion 14cms longer (and make sure the up/downhaul is connected to the end in future).

But I'd be grateful for any advice on whether that rule of thumb for spinnaker pole length is about right?

Thanks...John

 

[Seajet]

jcpa,

my rule of thumb ( disregarding any class or racing rules ) is to have the spin pole a good 1' longer than the forestay, to protrude beyond it on a close reach.

If one fancies dip pole gybing the pole should still fit inside the forestay at deck level.

I find the pole uphaul is the important component, though for relaxed cruising with girlfriend crewing a tri-radial chute makes life much easier and saves my ears from an acoustic or physical beating !

 

[Rigger Mortice]

You could fit a bridle at the pole ends so that the up/down hauls can still be fitted at the centre. I suppose that, with a telescopic pole, you would need different length bridles.

 

[john_morris_uk]

j
If one fancies dip pole gybing the pole should still fit inside the forestay at deck level.

That's a bit ambiguous? Do you mean that the whole of the pole needs to be at deck level?

The normal routine for a dip pole gybe is that the pole must be up the mast at the inboard end sufficient for it to dip inside the forestay.

IIRC you can have any length pole you like under racing rules (so long is its not one design) but there is a rating penalty for a pole that exceeds J (If I haven't quoted that exactly right then don't shoot me!)

To the OP - if you are not going to race then have any pole length you like, but if you exceed J by very much it will become unwieldy and give you excess storage problems.

 

[lustyd]

Can we assume you mean 1' longer than the distance to the forestay? My forestay is longer than my boat so 1' longer would look silly

jcpa,

my rule of thumb ( disregarding any class or racing rules ) is to have the spin pole a good 1' longer than the forestay, to protrude beyond it on a close reach.

If one fancies dip pole gybing the pole should still fit inside the forestay at deck level.

I find the pole uphaul is the important component, though for relaxed cruising with girlfriend crewing a tri-radial chute makes life much easier and saves my ears from an acoustic or physical beating !

 

[Seajet]

Say the spinnaker pole is attached to the mast, then held horizontal - ideally by a pole uplift line with a downhaul line too to keep everything under control.

If reaching in fresh winds a jockey pole may be required to give the spin' sheets and guys a good lead away from the shrouds.

Back to basics, the spinnaker pole needs to protrude a good 1' beyond the forestay when said pole is horizontal, but should be short enough to fit inside the lower forestay tang at deck level, this may involve pushing the spin pole up its' track on the mast when performing a gybe, so as to fit the pole inside the forestay; this is quite standard.

 

[jcpa]

Thanks for your comments

Thanks everyone for your helpful comments.

We did have to dip-pole gybe but that's another story (One of the end-fittings was cracked and I had to replace it - but Selden have changed the design, and the new one won't fit in the mast fitting - so it has always to go on the sail). We did try a dip pole gybe with the pole at 3.6m, but maybe we had to raise the mast fitting up the track a bit (Pythagoras says 1.8m would just have done it). Geometry also says that at 1.8m up the mast, and with rig dimension I=10.6m, the distance from mast to forestay should be about 2.6m, so a 3m pole would be about 1'-4" beyond the forestay. Maybe I should just cut my new inner section to the original length.

You could fit a bridle at the pole ends so that the up/down hauls can still be fitted at the centre. I suppose that, with a telescopic pole, you would need different length bridles.

Yes, I have thought about a bridle, maybe with loops and a snap shackle so I can set it to different lengths. Still thinking about this.

Anyway, thanks all

John

 

[Keen_Ed]

Originally Posted by Seajet
If one fancies dip pole gybing the pole should still fit inside the forestay at deck level.

That's a bit ambiguous? Do you mean that the whole of the pole needs to be at deck level?

The normal routine for a dip pole gybe is that the pole must be up the mast at the inboard end sufficient for it to dip inside the forestay.

IIRC you can have any length pole you like under racing rules (so long is its not one design) but there is a rating penalty for a pole that exceeds J (If I haven't quoted that exactly right then don't shoot me!)

To the OP - if you are not going to race then have any pole length you like, but if you exceed J by very much it will become unwieldy and give you excess storage problems.

(J is the distance between the forestay and the mast at deck level)

It's perfectly possible to dip gybe overlength (longer than J) poles. The old ACC boats used to have massively overlong poles, and they managed it (with expert crews, admittedly). You hoist the inboard end of hte pole up the mast so that it can dip down and though the forestay.

Good idea to mark the car position on the mast, and the topping lift so that the pole can make it through. Makes life simpler.

"Normal" length nowdays is a foot or so longer than J. In the days of the IOR, normal was j.

 

[jcpa]

Thanks again for the comments - including whether I intend racing.

I do intend doing a few races, but not seriously.

We did go 'Round the Island' this year in ISC, and spinnaker pole length was not part of the rating. Presumably it is part of IRC.

 

[Keen_Ed]

Yes

 

[Seajet]

(J is the distance between the forestay and the mast at deck level)

It's perfectly possible to dip gybe overlength (longer than J) poles. The old ACC boats used to have massively overlong poles, and they managed it (with expert crews, admittedly). You hoist the inboard end of hte pole up the mast so that it can dip down and though the forestay.

Good idea to mark the car position on the mast, and the topping lift so that the pole can make it through. Makes life simpler.

"Normal" length nowdays is a foot or so longer than J. In the days of the IOR, normal was j.

I'm sorry I didn't make it crystal clear, there was I thinking ' dip pole gybe ' inferred dipping the outer end of the pole, I also mentioned moving the mast end of the pole up on its' track.

Still, try lowering the pole horizontally to deck level to gybe if you fancy it; please let me know when you're going to do this so I can stand by with a camera.

 

[john_morris_uk]

(J is the distance between the forestay and the mast at deck level)

It's perfectly possible to dip gybe overlength (longer than J) poles. The old ACC boats used to have massively overlong poles, and they managed it (with expert crews, admittedly). You hoist the inboard end of hte pole up the mast so that it can dip down and though the forestay.

Good idea to mark the car position on the mast, and the topping lift so that the pole can make it through. Makes life simpler.

"Normal" length nowdays is a foot or so longer than J. In the days of the IOR, normal was j.

IMHO a perfect answer to the OP's question.

 

[William_H]

Spin pole

Dip pole gybing is normally for bigger boats where pole is too heavy to be end for ended by a forward hand.
It is best used with dedicated guy and sheet on each corner of spin.
I can't imagine that a telescopic spin pole would be used in that siuation so i presume it is on a smller boat.
Yes spin pole should when fitted to the mast extend about 20 to 30 cms beyond the forestay when horizontal.
Yes you should definitely use a bridle for topping lift connection and down haul if you use one. The bridle will tend to want to compress the pole but that should be oK. But it will have to be set up for your usual length.
If it were me I would be using just ordinary ali tube or even wind surfer mast for spin pole. good luck olewill

 

[lw395]

My last boat had a pole about 5ft longer than J on a 39ft boat.
We gybed it dip-pole, the end went a long way up the mast.
On smaller boats you can gybe a single ended pole by simply taking it off the mast and manually pulling the end back behind the mast while the uphaul takes the weight of the other end. Gets unwieldy as the pole gets heavy.
How long a pole you want depends on how long the foot of the kite is among other things.
On a close reach a longer pole is good, projects the kite out from behind the jib. My Merlin dinghy has 2.4m poles J is about 1.5m?
But a long pole means the guy operates at a worse angle, so will be loaded more, put more compression on the pole etc etc.

It's much easier to cut a bit more off later....

 

[merlin3688]

The length of a spinnaker pole is determined by the "J" dimension of your boat. The diameter of a spinnaker pole is proportional to its length in order to provide the necessary compressive strength.
The "J" dimension is the distance from the forward face of the mast to the outer most jib tack at deck level. This dimension is used by the sail maker to properly size the spinnaker for a given boat. Boats with fixed bow sprits can have very long "J" dimensions. This means that if you have a cutter, the "J" extends to the outermost jib tack, not the staysail tack. The only time this dimension is "altered" is in cases where a "J corrected" measurement is used or a "penalty pole" is used. These poles are a percentage over true "J" based on a set of criteria that varies from class to class. Your racing certificate will list your boat's maximum "J" and any penalties for longer poles.