Whisker pole sizing

[suiramor]

What determines the correct size of a whisker pole? Forespar recommendation for my boat (Ben Oceanis 461) is min 15ft, extending to 22. (The distance from the mast to forestay is actually 15ft). I am looking at a used pole that is 9 extending to 21ft. Its label says max boat length is 40. What determines that? I need a pole for light conditions only (max 15kn of wind). What am I risking with a shorter pole?

[GordMay]

Adjustable/telescoping whisker pole length is 100 percent of the foot length of your largest headsail, based upon masthead-rigged boats. Fractionally-rigged boats may require smaller poles. Boats with relatively heavy displacement, or with bowsprits, should use the next larger pole size.

From Forespar’s ‘Whisker Pole Seminar’:
"... Whisker poles should be 100% of the foot of whichever headsail is being flown.
Measure from the tack to the clew and the whisker pole should be this length. You need to have some overlap in the pole.
Poles telescoped to their maximum length are at their weakest, strength-wise. Diameter is a major function of strength. A 2-1/2" diameter tube is as much as 70% stronger than a 2" diameter tube ..."

➥ https://www.forespar.com/whiskerPoleSeminar.shtml

Forespar has an alphabetical Whisker Pole Selection Guide on their website. It allows you to just click on a boat manufacturer.
➥ https://www.forespar.com/DownwindPoleByBoatModel/

[dlj]

Originally Posted by GordMay

Adjustable/telescoping whisker pole length is 100 percent of the foot length of your largest headsail, based upon masthead-rigged boats. Fractionally-rigged boats may require smaller poles. Boats with relatively heavy displacement, or with bowsprits, should use the next larger pole size.

From Forespar’s ‘Whisker Pole Seminar’:
"... Whisker poles should be 100% of the foot of whichever headsail is being flown.
Measure from the tack to the clew and the whisker pole should be this length. You need to have some overlap in the pole.
Poles telescoped to their maximum length are at their weakest, strength-wise. Diameter is a major function of strength. A 2-1/2" diameter tube is as much as 70% stronger than a 2" diameter tube ..."

➥ https://www.forespar.com/whiskerPoleSeminar.shtml

Forespar has an alphabetical Whisker Pole Selection Guide on their website. It allows you to just click on a boat manufacturer.
➥ https://www.forespar.com/DownwindPoleByBoatModel/

I had to check out their selection guide - as I expected, my boat is not listed. I did send them an email telling them as requested on that page.

dj

[two-rocks]

That 3-section pole is probably very weak, and I don't think it's recommended for larger sails.

The huge advantage to the pole is having the ability to shorten sail as needed - something for light winds only is like sailing on sunny days only - things change.

If you never use it in medium or more air, go for it (non spinnaker racing?). We love our whisker pole, but in light air nothing beats the fun of the assym...

[Tsuru]

Length and strength determine the right whisker pole. If you use a smaller pole in light winds you could get away with it, but I’d recommend staying close to the Forespar guidelines. Truth is a whisker pole is indispensable sailing in strong downwind conditions.
It would be very easy to damage a smaller pole as the wind picks up. The pole does a great job keeping the sail stable, until it bends in the middle.

[GordMay]

A Whisker Pole [length] is sized to match the foot [or ‘LP’] of the foresail, not [necessarily* the boat].
A larger headsail requires a longer pole; hence the use of telescoping poles, to suit multiple sails [or roller reefing].


Genoas, by definition, have a clew which extends past the mast [‘LP’ longer than ‘J’] and are described by the amount by which they do so. For instance a 135% [#2] genoa has a foot [& ’LP’] 35% longer than 'J', and a 155% [#1] genoa is 55% longer.

* Except with a working jib [100% right-angled triangular sail] that exactly fills the fore triangle [but no more or less], and with a foot that's parallel to the deck. In this case ‘LP’ matches ‘J’.

“Foot” measurement = The distance from tack to clew.

“J” [boat dimension] = Foretriangle base, or distance between the headstay termination [at the deck] and the front of the mast at the sheer line.

“LP” [sail dimension] = Luff Perpendicular, or Shortest distance between clew and luff.

[GordMay]

All of the aforementioned is to say:
A 21 Ft [max extension] pole, on a boat with a 15 Ft “J”, will be useful with a headsail up to ±140% [#2 Genoa]; but may be weaker than ideal [small diameter].

[dlj]

I'm not a racer, but someone told me there are rules in racing where the whisker pole can't be longer than J in your diagram above - is that correct?

dj

[Adelie]

Originally Posted by dlj

I'm not a racer, but someone told me there are rules in racing where the whisker pole can't be longer than J in your diagram above - is that correct?

dj

I’ve read that the Spinnaker pole is not allowed to be longer than J for racing.

For cruising it doesn’t matter, we aren’t subject to racing rule limitations.

As Gord previously indicated, 100% of your largest foot length is a good whisker pole length.

[dlj]

Originally Posted by Adelie

I’ve read that the Spinnaker pole is not allowed to be longer than J for racing.

For cruising it doesn’t matter, we aren’t subject to racing rule limitations.

As Gord previously indicated, 100% of your largest foot length is a good whisker pole length.

Have you run a double head sail rig (commonly called cutter rig) with double whisker poles? And did you use two different sized pole for the fore sail and stay sail?

Another question that I've been looking into - I've heard some folks use a double head sail for down wind passages - that some of the roller furlers have two slots in them so you can run two sails in the same furler. I happen to have a furler like that, and have been wondering how you handle that sail set-up. I'd think you'd want two identical sails, so would you put two identical whisker poles on each?

I know it's a bit beyond this thread, but if someone could point me to a more detailed explanation of that setup, I'd be most interested. I've to date only found passing remarks about this kind of foresail setup.

dj

[wholybee]

The 100% rule that Gordmay cites is just a general suggestion. When using a pole the foresail is generally poled out to windward. And the further it is poled out, the further to windward you can sail. For a larger Genoa, 100% LP is fine. But for a jib that fits within the foretriangle, you might want something longer than 100% LP.

A spinnaker pole is limited to the J measurement in racing rules. Whisker poles are usually longer than this. I would say that the J measurement should be the minimum length you should consider for a whisker pole-would work but leave you wishing for more.

I have run a double headsail on a furling jib. It worked REALLY well, and was easy for me to handle single handed. Both sails need to be raised at the same time, both attached to the swivel, so that they can furl together. The pole needs to be setup with a topping lift, foreguy, and an afterguy, so that you can furl the sail, and the pole stays put. Typically, the windward jib is on the pole, and the leeward jib flys normally. Or, if you can add a second pole, you can steer from about 140-140 without needing to jib. There is also the option of using the boom as a second pole by running the jibsheet through a block on the end.

Anyway, it is a really slick setup, and if the wind picks up, you can reduce sail by furling them, or in an emergency can completely furl them both, and not even have to worry about the pole, it just stays put. With the headsails furled, you can take your time jibing the pole if you need to, much easier than jibing a spinnaker. With a 130%, a 100%, and a full mainsail, I was just as fast as I was with a spinnaker-without the fear of rounding up and broaching, without needing constant trimming, and with a really wide "grove" to steer in.

[dlj]

Originally Posted by wholybee

The 100% rule that Gordmay cites is just a general suggestion. When using a pole the foresail is generally poled out to windward. And the further it is poled out, the further to windward you can sail. For a larger Genoa, 100% LP is fine. But for a jib that fits within the foretriangle, you might want something longer than 100% LP.

A spinnaker pole is limited to the J measurement in racing rules. Whisker poles are usually longer than this. I would say that the J measurement should be the minimum length you should consider for a whisker pole-would work but leave you wishing for more.

I have run a double headsail on a furling jib. It worked REALLY well, and was easy for me to handle single handed. Both sails need to be raised at the same time, both attached to the swivel, so that they can furl together. The pole needs to be setup with a topping lift, foreguy, and an afterguy, so that you can furl the sail, and the pole stays put. Typically, the windward jib is on the pole, and the leeward jib flys normally. Or, if you can add a second pole, you can steer from about 140-140 without needing to jib. There is also the option of using the boom as a second pole by running the jibsheet through a block on the end.

Anyway, it is a really slick setup, and if the wind picks up, you can reduce sail by furling them, or in an emergency can completely furl them both, and not even have to worry about the pole, it just stays put. With the headsails furled, you can take your time jibing the pole if you need to, much easier than jibing a spinnaker. With a 130%, a 100%, and a full mainsail, I was just as fast as I was with a spinnaker-without the fear of rounding up and broaching, without needing constant trimming, and with a really wide "grove" to steer in.

How did you run your sheets? Did you run two starboard sheets through the same blocks? Did you add a block on each side? My blocks could easily handle two sheets going through them. Your description of ease of use and speed is what I've heard before. Then, when you aren't running both out, did you have to drop both, then put one back up? How did that work?

dj

[wholybee]

I had one sheet on each jib. As it happened on my boat the genoa sheet went far aft through the spinnaker block after using the boom as a pole, but you would use blocks wherever the angles work out. When you jibe (so that the two jibs switch sides of the boat) one sheet needs to go around the front of the forestay. Jibing, moving both the pole and flipping the sails to the other side, took about 5 minutes single handed, but was not difficult. Furl the sails. Go forward and move the pole. Then rerun the sheets. Then back to the cockpit and unfurl again. Then it will unfurl with the sails switched sides. If you head up so that you don't need both sails, they can both go to the same side of the boat and function like one (very thick and heavy) sail. That can be done quickly without leaving the cockpit.

Yes, you would need to drop both sails, and then raise only one to switch back to a normal setup. It is something you would decide before a passage and change back after the passage is done. But you could reasonably leave it that way for the entire pacific crossing.

[dlj]

Originally Posted by wholybee

I had one sheet on each jib. As it happened on my boat the genoa sheet went far aft through the spinnaker block after using the boom as a pole, but you would use blocks wherever the angles work out. When you jibe (so that the two jibs switch sides of the boat) one sheet needs to go around the front of the forestay. Jibing, moving both the pole and flipping the sails to the other side, took about 5 minutes single handed, but was not difficult. Furl the sails. Go forward and move the pole. Then rerun the sheets. Then back to the cockpit and unfurl again. Then it will unfurl with the sails switched sides. If you head up so that you don't need both sails, they can both go to the same side of the boat and function like one (very thick and heavy) sail. That can be done quickly without leaving the cockpit.

Yes, you would need to drop both sails, and then raise only one to switch back to a normal setup. It is something you would decide before a passage and change back after the passage is done. But you could reasonably leave it that way for the entire pacific crossing.

I'm trying to fully envision your explanation. I am understanding that you were running two different sized genoa's, a 100 and a 130, correct?. So the 130 would run on the leeward side, no? Therefore, you had to do that switch with running the sheet forward of the forestay when jibing... But if running two sails the same size, I think you'd never have to do that. Interesting, you are running the boom as a whisker pole. So doing that, you may still have to switch sides of boom and whisker pole. No big deal... I'll have to think about the less flexible sails option if running two sails the same size. I'm not sure about that limitation. But I sure like the idea of this kind of setup... How much do you think the double sail thickness affected heading up wind?

A lot of food for thought. Let me know if I'm missing anything here...

dj

[wholybee]

Originally Posted by dlj

I'm trying to fully envision your explanation. I am understanding that you were running two different sized genoa's, a 100 and a 130, correct?. So the 130 would run on the leeward side, no? Therefore, you had to do that switch with running the sheet forward of the forestay when jibing... But if running two sails the same size, I think you'd never have to do that. Interesting, you are running the boom as a whisker pole. So doing that, you may still have to switch sides of boom and whisker pole. No big deal... I'll have to think about the less flexible sails option if running two sails the same size. I'm not sure about that limitation. But I sure like the idea of this kind of setup... How much do you think the double sail thickness affected heading up wind?

A lot of food for thought. Let me know if I'm missing anything here...

dj

Yes, I think you get it. I used 2 different sized sails because that is what I have. Most boats would carry several sizes of jibs, but not often 2 the same size. With 2 the same size, jibing is easier. I have also seen boats with 2 equal sized poles, both set with toping lifts, forguys, and afterguys. The poles never moved, and there was no jibing anything except the main.

The setup did not sail upwind well. It worked in a strong breeze. Mostly, you should know if you will have an upwind leg before you leave. You shouldn't have anything upwind from Panama to Fiji.