Silly season starts .... How strong for a spinny pole ?

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We see boats lined up in marinas with spinnaker poles lashed down on deck ... along rails etc.

Now my question is .... given that a boat I had previous had a spruce boom .... about 12cm deep, less than 10cm wide .... and the spinny pole I had on same boat was about 8cm diameter ... (Alacrity 19) ... means the spinny pole of hardwood was near as strong - maybe stronger than the mainsail boom. Surely an overkill ... but it was sized correct by rigging table.

Is it really that necessary to have such strong poles for spinny's / genny poling out ? It has been known on many occasions when I was racing my 1/4T job in Tallinn - that we would forego the pole and use a boat-hook !! quick, easier - made the arms ache though !! but made fast change on short legs much better ...

Now what would be minimum size timber ? Alloy tube ? to create a spinny pole for a 25ft boat like mine ... similar sail-area to a Centaur / Colvic 26 ..... given that I do not plan to use a pole in bad weather !! and limited downhaul / uphaul fittings ....

My guess is the same or even slightly less than the pole I had on the above boat ... length of course to suit J.
 
i have a very light pole which is telescopic.I made it from two bits of alloy pole about 2 inch dia.(One bit slightly less)

I wouldnt attempt to fly the kite in more than about 12 knots of wind as it is starting to strain the pole by then.I keep meaning to get a stronger one but custom made are too dear for the amount I use it.


poling out the genoa is ok in stronger winds as I furl away enough sail to keep the pole from bending ,this seems about right for cruising purposes anyway.
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Your Spinnaker is likely to be bigger than mine as you are 3 ft more LOA and masthead rig I think?

Scuttlebut break over back on skirting board fixing before SWMBO sees me /forums/images/graemlins/tongue.gif
 
A broken windsurfer mast would be a far better bet. lighter than the alloy, and stronger, and only cost will be the pole ends.
 
I use an old windsurfer mast, not exactly as a spinny pole, but to pole out the genoa when running goosewinged (this is on a 31-footer).
It's an excellent bit of kit, cheap too, but this year I've found that the surface seems to be breaking down - when I handle the pole, my hands get covered in tiny fragments of glass that are coming out of the surface (which is grp with what looks like carbon-fibre reinforcing).
Not sure what to do about this, but I think I might try slapping a couple of coats of resin on it to try and re-seal the surface.
 
Boom = bending
Spi-Pole = compression (worst case, close reaching with the kite, pole just on the forestay)
The loading is very different from having the kite well aft on a run or broad reach or poling out a genney.
Small dia tube, gets out of column, snap.
You'd better buy a 6-pack of windsufer masts if that that the way you want to go as they are also mainly loaded in bend, the only compression they experience being from the downhaul.
You are an engineer, work it out!
 
I had an old fishing rod that started shedding fibres. It caused one of my kids some serious skin irritation before I binned it and cleaned out the forepeak.
 
Lateral strength is important in a spinnaker pole. When the pole is far forward and you are reaching ther can be large side loads as it bends round the forestay.

Also if youget a bad roll the lateral forces will be considerable if you dip the pole while moving forward
 
High Nigel the amswer to your question on pole strength is in the way you sail with spin. If you are gentle then light is no prob.
I have a section of carbon windsurfer mast currently as spin pole. about 11ft long. Yes i do worry about it snapping but the advantage in light weight when gybing is worth it.
It has a topping lift to the centre and down haul to the end and yesterday it had an alarming bend cos new crew didn't notice the excessive down haul. In my case it doesn't hang farforward of the forestay so bending on the forestay is not so much of a prob.
If you can get a windsurfer mast bottom section larger daimeter this should do you fine for a shortish spin polle. ie not for a giant spin. You can drill holes for the fittings on the end but don't drill near the centre of the pole.(that goes for aluminium as well) Use a bridle or in my case I wound carbon fibre strands around the pole and around 2 thimbles which formed a loop top and bottom for rope attachment and of course soaked it in epoxy.
Anyway our racing season started yesterday we had a 3 hr race with 2 nice spin runs and gentle breezes. We have a race scheduled today (bank holiday) with morning start but so far not a dribble of breeze. olewill
 
Hang on .... who said I\'m an engineer ???

I don't plan to stick up my spinny in anything other than light airs ... and in fact usually put it up without pole ..... I looked at chandlers offerings ... remembered my old one ... and my wallet cringed in shock !!
 
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