Spinnaker boom, right size?

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alex
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Spinnaker boom, right size?

Post by alex » Thu Feb 24, 2011 00:36 am

Hi all,

What would be the right size (length, perhaps also reasonable diameter) for spinnaker boom for FE83?

Alex

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Post by Petri » Thu Feb 24, 2011 01:15 am

Maximum lenght dictated by the class regulations is 2800mm and even though you would not race personally, for further use it might be good to have class "approved" equipment.

Thus anything not more than 50cm shorter (just a gut feeling the point being that if one does not race, it doesn't matter that much if the boom is say 20cm shorter than the allowed maximum but still, size matters) than the maximum will do the trick.

Typical diameter is around 5-6 cm,

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Post by alex » Thu Feb 24, 2011 08:45 am

Thank you Petri, 2800 mm that is then.

Diameter is important thing to me as I caught myself several times already that I tend to use thicker and stronger materials while calculations (or just common sense) tell it could have been thinner and lighter.

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Post by harald » Thu Feb 24, 2011 09:36 am

Hi Alex,

if you attach the topping lift and foreguy with bridles you can safely use an even smaller diameter. The original pole is like a telephone-pole, due to it having attachments in the middle.

There are some pictures in our gallery on the subject of splicing dyneema with shock-chord within. This is quite handy as the bridle retracts along the boom when not in use, things stay tidier that way.

I also recommend the bag for the pole that attaches onto the main boom. This allows the topping lift to be permanently attached to the pole, and you don't get a mess with sheets on the foredeck anymore. It costs a few tenners on WB.
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Post by alex » Fri Mar 11, 2011 00:51 am

Hi Harald,

Just went to watch the pictures. :-)

I have a doubt about the boom bag. The thing is I have topping lift which comes out of the mast top on the side of the mast. It makes some load to the side of the mast when boom is not supported by main sail. Spinnaker boom would add to the load. I am wondering if it is OK. And I also recall those videos when boom hits some sluggish guest right in his head... ;-)

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Post by risto » Fri Mar 11, 2011 09:04 am

alex wrote:Hi Harald,
I have a doubt about the boom bag. The thing is I have topping lift which comes out of the mast top on the side of the mast. It makes some load to the side of the mast when boom is not supported by main sail. Spinnaker boom would add to the load. I am wondering if it is OK. And I also recall those videos when boom hits some sluggish guest right in his head... ;-)
I'd say that the added weight on boom is a non-issue here, unless you are using some kind of a shoe string as topping lift. :-) And if it seems to be an issue, you can always take the spinnaker boom off the bag when not sailing, problem solved!

On the other hand, the added convenience in using the spinnaker boom from the bag out shines all other reasons not having it there hands down so I would like to say that this is the best way to keep the spin boom away from the deck.

If the bag is installed right there shouldn't be a worry in hitting the head of the sluggish guest with it anymore than there is without the bag and boom. The spin boom should sit more or less right on the side of the main boom, not underneath it.

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Post by harald » Fri Mar 11, 2011 09:52 am

I strongly recommend Barton's Boomkicker. It's a device that installs right under the main boom, along the kicking strap. It keeps the boom level without a topping lift. As an added bonus the mainsail gets a better shape in lighter winds when the weight of the boom doesn't oversheet the main. Without a boomkicker or some other lifting device the leech usually closes due to the weight of the boom.
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Post by alex » Sun Mar 13, 2011 14:06 pm

risto wrote:On the other hand, the added convenience in using the spinnaker boom from the bag out shines all other reasons not having it there hands down so I would like to say that this is the best way to keep the spin boom away from the deck.
This is very true, yes.

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Post by alex » Sun Mar 13, 2011 14:10 pm

harald wrote:As an added bonus the mainsail gets a better shape in lighter winds when the weight of the boom doesn't oversheet the main. Without a boomkicker or some other lifting device the leech usually closes due to the weight of the boom.
Makes good sense. Perhaps I have to go shopping. :)

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Post by alex » Mon Mar 14, 2011 21:19 pm

Interested, does WB-Sails main sail cover also cover attached spinnaker boom? Does anyone know? Harald, I guess you have main cover from WB-Sails?..

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Post by harald » Mon Mar 14, 2011 21:25 pm

We have a no-name cover, but I don't think this is gonna be a problem. The spinboom isn't that thick.
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Post by alex » Mon Mar 14, 2011 21:26 pm

harald wrote:We have a no-name cover, but I don't think this is gonna be a problem. The spinboom isn't that thick.
Thanks, that was fast. :)

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Post by Panu » Tue Mar 15, 2011 15:01 pm

alex wrote:Interested, does WB-Sails main sail cover also cover attached spinnaker boom? Does anyone know? Harald, I guess you have main cover from WB-Sails?..
Hi all

We have WB main sail cover and attached spinnaker boom holder and it works quite well together. No problems at all. Our cover is quite old from year 1990. I can't say that WB's cover design is still the same..?

Anyway there is no way I would place the spinnaker boom back onto the deck.
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Post by alex » Wed Mar 16, 2011 10:00 am

Panu wrote:Anyway there is no way I would place the spinnaker boom back onto the deck.
Yes, yes, I am convinced. :)

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Post by VVille » Thu Mar 17, 2011 00:09 am

The spinnaker boom and its bag fit inside our old mainsail cover without any problems, the difference is smaller than the difference between poorly and well folded mainsail. This winter we bought new cover from WB-sails and they said that the normal cover works also with the spinnaker boom on main boom without any problems.

I recommend that you get boom with ends shaped like this new Selden end http://shop.spars.co.uk/534-865-01-spip ... 3452-p.asp . Many manufacturers make these. Avoid the old Selden type ends which open towards the end of the boom (axially) rather than up/downwards (radially). The difference in ease of use is quite large.

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