Spinnaker again - what size?

Roach1948

Roach1948

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www.dallimoredesigns.nl
As Roach has never had a spinnaker (as far as I know) I was wondering how one would calculate the size of a fractional spinnaker on a classic? I want to get some quotations at the LIBS and see if I can get a Winter deal.

I do have a very small sailplan of Roach taken from a magazine around the time of her launch, but no spinnaker markings are on it. Well its not that clear for the other sails either. Main is 160sq ft and working job is 65sq ft. Maybe this helps give more of an idea of the size I require. Quite small I would presume.

I also know the dimensions of the fore-traingle. 8 1/2" mast to bow and 19" mast base to jib block - I suppose the spinnaker block should be placed a foot or so higher than the jib block?

Anybody with out there who can give me some advice as I am not that au fait with spinnakers?
 
It depends on the type of Spinnaker. A tradition leg of mutton sail will go inside of the forstay and get poled out to one side. Where as a modern symetric of asymetric will go from either around the area of the jib halyard or the mast head.
 
I was thinking along the lines of a conventional poled-out symmetrical tri-radial for running.

Oh - and I think I will keep it a fractional spinnaker as I think I could over-power the rig from the masthead. She is 3/4 fractional at present.
 
I was looking at the B&W photo on your blog, and I can't help feeling that an assymetrical cruising shute would be more versatile and easier to handle, on the other hand, I do appreciate that it probably would not suit the "originality" of the boat?

As to size? Fractional rigged Folkboats use a small spinny, could you not see what size it is on those, and drop back a bit for the size of your boat? Just a thought, sorry if it's not much use.

PS. Seateach do very reasonably priced spinnies etc, they also have a pre-used page, and there are some bargains to be had on there from time to time. Not much use until you know what size you want, I know, but may be worth a look for future reference?

http://www.seateach.com/Sails.asp
 
Thanks Smiffy. I like the lateral thinking.

Anybody know where I can get a good Folkboat sailplan (Just done a google and I can't find one with dimensions on it)? Then I can compare and reduce to the correct ratio for Roach. (When I bought Roach she came with an extra FB mainsail - I presume previous owner was going to adapt it. It was close fit; A tad shorter on the foot and a few feet longer in the luff if I remember rightly, so they are not that far out really).

For cruising an asymmetric would be handier - I agree, but as next year I will be launching and attending the Royal Burnham One Design 75th year anniversary - I would like a trad spinny in order to have a (gentlemanly) go around the cans. You got me thinking now and maybe I can use a RBOD spinny...
 
Luff and Leech is 21.2 ft width across foot is 11'10" getting confirmation by fax, will let you know by PM /forums/images/graemlins/smile.gif
 
Thanks but I missed it.

Not to worried though as I prefer to work out the dimensions first. It would have needed to be cut down anyway and I think on such a small spinnaker costs involved could mount up to a large % of the labour involved making a new one.
 
Thanks Smiffy, trying to remeber how to do Ratios! This classic boat lark is great for re-aquainting schooltime arithmatic!

PS I think I stuffed the rigging up already with my hypotenuse calc. going wrong - also forgot to measure the toggles!!! We will see in Spring whether or not I got it right...
 
No probs. Sadly that sail was VERY close to what I need - but quite a bit smaller than what folkboats can race with. The dimensions I have worked out in the end (and sorry for going metric on a classic forum - but sailmakers seem to prefer it this way) is foot 3.35metres and luff/leach 5.85.
 
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