what pole: Spinaker, or Whisker ?

[YARGESOL]

Going to add a pole on my cat for downwind sailing. I have 46 cat with 100% foresale, the main and ASY. I think I need a 13-24 Whisker. But, maybe Spinaker pole will be better ? Thanks for any advise

[roverhi]

You'll want at least 3.5"/3" diameter pole and probably larger, if they make one. The longer the extension that you'll use, the larger diameter a whisker pole needs to be. Pretzeled 3"/2.5" whisker pole extended out about halfway in moderate conditions on my 35' mono. Switched to the over length 3.5" diameter "penalty' spinnaker pole for the final 12 days of the passage. The extended whisker pole made for a better setting 135% genoa.

[44'cruisingcat]

Have you tried mounting a block out near the lifelines, and sheeting through that downwind? It's pretty unusual for a cat to need a whisker pole.

[jaybird1111]

Assymmetrical chutes use sprits, not poles nor whiskers

You might want a whisker to pole out your jib. Maybe. On a cat, you've got that beam thing going for you. (see 44cruisecat's post above)

[Training Wheels]

And if you don't have a sprit, you can tack the ayso to the windward bow, or use a bridle between both bows.


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[Stumble]

Hmmm,

I this case there is no reason to get a telescoping wisker pole. The ideal wisker pole leingth is the same leingth of the foot. In this case with a 100% jib the foot is the same as a spinnaker pole. For the same size a spin pole is going to be substantially stronger.

For a big boat I would also suggest considering carbon over aluminium. It's a big price hit, but the weight difference is substantial.

[tomfl]

Originally Posted by Stumble

Hmmm,

I this case there is no reason to get a telescoping wisker pole. The ideal wisker pole leingth is the same leingth of the foot. In this case with a 100% jib the foot is the same as a spinnaker pole. For the same size a spin pole is going to be substantially stronger.

For a big boat I would also suggest considering carbon over aluminium. It's a big price hit, but the weight difference is substantial.

Not an expert on this but it seems to me a narrower monohull would need a longer whisker/spinnaker pole than a wider multihull, simply due to the difference in beam assuming the multihull pole was mounted on stays.

Also wonder about how the greater apparent wind shift due to the greater speed of a multihull (at least in most cases) changes the ideal pole length.

Anyone have a source for the theory of sizing poles.

[Colin Oslo]

In any case, if you can afford it, go for Carbon, much easier handling!

[barnakiel]

Pole on a cat?

Pictures?

b.

[jaybird1111]

Originally Posted by tomfl

Anyone have a source for the theory of sizing poles.

I'm designing a sprit for my catamaran, and my sailmaker told me, 'make it as long as you can.' for whatever that's worth

[Stumble]

Originally Posted by tomfl

Not an expert on this but it seems to me a narrower monohull would need a longer whisker/spinnaker pole than a wider multihull, simply due to the difference in beam assuming the multihull pole was mounted on stays.

Also wonder about how the greater apparent wind shift due to the greater speed of a multihull (at least in most cases) changes the ideal pole length.

Anyone have a source for the theory of sizing poles.

A pole of either type should ever attach to the shrouds. They should only be attached to the mast, either on a ring, or a pole fitting. Attaching them to the standing rigging can apply a huge amount of leeward force to the rigging, and may contribute to mast failure.

The leeward projection of a jib is determined independent of the width of the boat. And has to do with the ideal trimming angle for the clew. While it maybe that there is no reason to use a wisker pole on a cat (or a reduced need for one) since a very wide barber haul can be fitted, the deck width is immaterial, it is the leingth of the foot of the sail that matters.

As for theory of a pole... The point of a wisker pole is to move the trim lead angle further outboard to allow proper leach control of the jib when the sheet is eased. It in effect acts the same as a vang for the main. How far out the angle needs to be is controlled by the clew height, and by the foot leingth. Assuming the jib car is placed properly than the ideal position would be defined by an arc with the tack as the fixed point and the radious being the distance between the tack and the jib car.

In practice the normal recomendation for a wisker pole is to make it the same leingth as the foot of the sail. Alternatively when jib reaching, or on a very wide boat a barber haul is probably a better option.

[Stumble]

Originally Posted by jaybird1111

I'm designing a sprit for my catamaran, and my sailmaker told me, 'make it as long as you can.' for whatever that's worth

For an asymetric absolutely. There is no sailing advantage to a shorter sprint.

For a symetric spinnaker pole it is normally set as the same leingth as the boat's J measurement. However a longer pole can be used with a rating penalty ascribed. Using a shorter pole is not a good idea since it can allow for the pole to pass inside of the forstay. When this happens all kind of bad things happen, like being completely unable to control the spinnaker at all until it is taken down and rerun.

For a wisker pole the normal recomendation is the same leingth as the foot of the sail.

[elandra65]

Hi,

try to avoid a telescoping whisker pole at all costs. They work great when they are not broken as it holds the foot of the headsail out well (pole same length as the foot). However I have had repeated failures with a "Forespar" 15-27 foot pole on a 50' mono crossing the Pacific. OK in under 10 knots apparent but destroyed the insides twice and bent the pole in less than 20 knots apparent. An expensive load of rubbish. I believe they are incorrectly engineered. If i started again I would probably have a headsail with foot = J and use a non telescoping spinnaker pole = J mounted on the face of the mast. Slight performance hit but much more peace of mind.

regards

Andrew

[django37]

I use a 6,6 m long carbon pole for the spinnakers and sometime the gennaker. This gets the sail better out of the mainsail shadow, when going deep downwind. Also have a 3,6 m pole for the genoa. Slower boats need long poles. Very fast boats will do with bow-sprit/prodder

[barnakiel]

The theory is not based on J. It is based on (I think) LP (and if it is not LP then what I mean here is the 90 degs line to your outer forestay). Ask your rigger or your sailmaker.

The calculation is a plain 1.4142 (=sqrt (2)) of LP. This is so because you want square angle with the longitudinal or thereabouts.

Just put the vision on paper and it is clear how long the pole needs to be.

A telescopic is best because it allows us to use it on various sails, various stays and at varying degrees of reef (roll). Selden makes decent ones. A carbo toy is very nice if the pole is a longer unit that goes with a heavier boat/bigger sails.

Cheers,
b.