tophatyachts.com

Can anyone give me a length of the pole to hold out the genny?

G'Day Rob,
This question has been raised a number of times. I posed the question to Jim Orrell who was an Australian Racing Judge. He currently sails an Endeavour on Lake Macquarie, thus you will see the reference to the Endeavour. Jim also runs "Learn to Sail by Mail", a correspondence course for learning to sail.
Note; Dimension "J" is the measurement from the base of the mast to the forestay at the deck. I made my pole "J" but it is, by this answer, too short. I hope it helps.

"Hi Greg there is no rule as such.
The spinnaker pole length can be limited by Class or rating rules.
IRC and similar rating rules do not apply to a Top Hat.
If there are Class rules for a Top Hat, you would need to check them.
If there are no Class rules or if there are, they are silent, then there is
no length limitation.
But I am sure the Top Hat designer would have an optimum length.
It is usual for a spinnaker pole to be about the length of J + 1 foot
(300mm)In considering the length of the pole two considerations come into play.
If poling out a headsail what length of pole is need to effectively hold the
clew of the headsail out to obtain as flat as possible headsail shape.You
will have noticed on the Endeavour our pole length produces an optimum shape
with our No.2 headsail but not as flat with the No.1. So the pole length is
related to the LPG of the sail. ( LPG is the perpendicular distance from the
headsail clew to the luff.). The pole needs to be somewhat longer. Consider
a triangle formed by the J, the LPG and the pole.The pole forming one side
will be the longest side.If the J and LPG measurements are known then
trigonometry can work out the length of the pole.
The other consideration is the foot length of the spinnaker. Spinnaker
dimensions are usually specified in Class rules.Here again you are trying to
project the clew of the spinnaker as far out from the bow as possible to
obtain a flat shape.The pole length will be related to half the foot length.
I am sure a sailmaker could give better estimates for a pole length."

I hope that helps.
It seems "J" plus 300mm is the go.

Greg.

'J' from the Top Hat drawing is 10' so with Jim's 300mm it would come to about 11'.

I tried poling out our new #1 on Sunday with the spinnaker pole (8') and my arm and got about 10' 6" so 11' looks pretty good.

The Top Hat drawing also gives details of an adjustable spinaker pole using 9' of 2" aluminium tube with snug fitting wooden internal pieces however I can't quite read the fine print.

John (Bear) can you enlighten us please?

Cheers,

Tom

I tried my spinnaker pole and it seemed to long (not to mention heavy) I'll get some measurments this weekend.
The guy in the pen opposite me has one thats a couple of feet shorter than his spinnaker pole and is only about 50mm in dia.

hello Top Hatters

Regarding spinnaker poles etc

Please find drawings attached . If I go down to Egret II this weekend I will measure my poles but my spinnaker is 460sq ft with wire luffs .


Cheers Bear

Hey Bear, how about posting those sail plans as pdf's in various files in the gallery so I can get a copy, please?

kind regards
Rob

Hi Rob,

Timely that you should ask the question last week as I had just bought a #1 genoa and did not have a wisker pole.

I ended up making one 12' long and it works fine with the #1 but I have not tried it with the #2 yet.

Didn't use a bridle but fitted a saddle to the outer end for the topping lift.

I used 2" diameter .080" wall thickness tube with plastic Ronstan ends.

Quite difficult to fine a home for it on board however!

Cheers,

Tom

Bear (this has nothing to do with whisker poles), I am impressed with your pictures of the original plans information. However, I think the Top Hat sail plan has been modified at some time since their publication. Which could explain why our boats can be a handfull sometimes.
I have before me a sail plan which provides the following stats.
Mast length: 9400 mm.
Mainsail: Luff- 8229mm / 27ft.+/- 3 inches.
Foot- 2895mm./ 9ft. 6inches
Leech-8534mm./ 28ft.
Source: http://homepage.mac.com/clatimer/.Publi ... ilPlan.jpg
date 2/03/2009.
Conclusion: I think we are carrying more sail than Illingworth and Primrose had in mind!

SOMBRERO John.S