Flying Fifteen Boom Vang

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IainR

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I've got an old classic flying fifteem (#848). It's been sailing well, but the boom vang is awkward, rusting, and today I realised the block it was attached to was rotten. Anyway I've stripped it all out and it needs replacing. Or at least repairing, but I thik the old leaver system was awkward and heavy.

Haven't done much work on boats before, so some advice please, I was thinking of a simple 4:1 pulley system, nothing fancy.

Will this suffice? Or should I go for an 8:1, similar to that shown on here:

http://www.laserinternational.org/rules/rulchovw.htm

Any other suggestions?

I'm not looking for any top draw system, just fit for purpose. Allow me to sail and race the boat well enough.

Cheers

Iain
 
I would say 16:1 is more the mark for a FF. That's what we use on our Merlin. The simple and easy way is make a cascade system. You will need some 4mm Spectra and 4 strong single blocks.
 
Looks good but Harken won't come cheap. Cheaper to make your own and lead back to either side of the boat so the helm can adjust from either tack. Have a look roud the dinghy park for some ideas.
 
I used to use an 8:1 system on my Fifteen and for what you want I think that is quite enough but do run it so that you can trim from either tack, i.e. double ended or similar.

I agree with Harken cost- I never used anything else and it is good kit but if you are entering the Classic series races do you really need to mix it with the Ovington boys?- I think not so find yourself some decent ball bearing blocks and pulleys at a sensible price
 
The thing with vangs is not just the pulley ratio but the location of attachments to the hull and boom. If you can attach the bottom of the vang to the mast step or if possible even lower but as close to the mast (fore and aft wise) as possible then you can get more leverage. If the base attachment is up the mast toward the gooseneck you will see from trigonometry that there is more force pulling the boom into the mast than down toward the deck. The location of the attachment along the boom has almost no effect on the leverage to pull the boom down. Further along the boom gives more leverage against the clew of the sail cos it is closer but then the angle of the vang causes more pressure into the gooseneck.
So if you had a vang attached on the mast near the keel going to a point say 700mm below the gooseneck you would find that 4 to 1 would be more than enough to get the force down at the clew while in my boat of similar size the mast is stepped on the cabin with only about 300mm to the gooseneck such that a huge vang ratio would still tend more to crush the gooseneck than pull down the clew. So I don't use a vang but rely on a full width traveller and use the main sheet to pull down the boom even when running. This arrangement is especially usefull when running a spinnacker shy in strong winds and I want to dump the mainsail pressure by letting the mainsheet out which also allows the boom to rise depowering the main even more. Anyway just a few thoughts. Tandem 2 to 1 systems seem better than tryng to do it all in one multisheeve block. olewill
 
Lets remember here that the kicker is probably the most important control in a racing (any?) yacht. It controls the twist of the mainsail and the tension in the leech of the sail. The kicker must be quick and easy to adjust, ideally by either helm or crew from the sitting out position.
 
Cheers all,

I've just been to the local chandlery, and jesus this may cost.

I 've been looking more at the 8:1, cascaded vang.

It's shown at the back of the Ronstan Catalogue (pg 117).

It's used on J24's so would be suitable for FF's I'd guess. I have to look more at what attachements I have around the mast. the old system worked through the shackle for hoisting it in and out.

Still unsure. The other, more expensive, option is the 16:1.

Any more advice appreciated.

Cheers

Iain
 
Ended up going for a double cascaded 16:1, Lewmar system.

Including spectra cost about NZ $ 270, so a little over 100 quid.

Gets delivered on Friday so I'll see how it sets up, the main price is the fiddles so making ot 8:1 or 16:1 is only $50 difference.

Cheers

Iain
 
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