Admiral Hornblower

added speed from a spinnaker

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I think a true symmetrical spinnaker would add some speed on a beam reach. The increase would probably be disappointing on a run. The big excitement of adding an asymmetric spinnaker is the higher angles you can sail and more apparent wind. If you can sail a modified Sidewinder ( with symmetrical spin ) try it first before you lay out the cash to modify your boat. Happy Sailing!

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Tests have shown that an asymmetrical spinnaker on an under-powered, heavyish boat is not better generally than a symmetrical one because they can't generate enough apparent wind in a broad enough range of wind strengths to make up for the extra distance they need to travel to get downwind. The issue is discussed in Frank Bethwaite's second book.

I suppose it might be faster on a reach, but that would be the limit of its speed advantage over a symmetrical one.

The photo's I've seen of the boat indicate it has a lightly supported rig. So any spinnaker will not be able to be flown from much above the hounds and will therefore be pretty small (as the questions suggests).

But any spinnaker will make the boat faster off the wind, including running square. But of course the ultimate problem with running square is that the apparent wind diminishes as the boat sails faster, so there is always a limit on what any amount of extra sail area can achieve. .

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Spinnakers make surprisingly little difference to speed round the track, I think its typically single figures percent. Now that includes time upwind as well, so the actual effect of the kite when used will be rather greater.My very lightly informed guess, not knowing the boat would be 20% would be the most you could expect in ideal conditions and wind direction, and round the rest of the polar much less.

 

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Assy is way easier to handle than sym. And a couple % faster is true, but it's 3x the fun.

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100 sq feet is a waste of time. Go big or go home. Get an old 505 spin. OR a Thistle spin. Go symmetrical. -- Just use a symmetrical pole.  If you want, you can fly an asymmetrical off it for light wind reaching if you want to. You are just fooling around.

Just find a spinnaker. But get a big one!

Lighter wind, downwind with a spinnaker will increase your speed considerably. IT all depends on the size! You put a Thistle spinnaler omn in 7 knots and sail 145 true (just keep the apparent abeam and pole at forestay) you will be planing!

 

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8 hours ago, fastyacht said:

100 sq feet is a waste of time. Go big or go home. Get an old 505 spin. OR a Thistle spin. Go symmetrical. -- Just use a symmetrical pole.  If you want, you can fly an asymmetrical off it for light wind reaching if you want to. You are just fooling around.

Just find a spinnaker. But get a big one!

Lighter wind, downwind with a spinnaker will increase your speed considerably. IT all depends on the size! You put a Thistle spinnaler omn in 7 knots and sail 145 true (just keep the apparent abeam and pole at forestay) you will be planing!

 

 

Agreed. With the caveat that an inexpensive 2nd hand spinnaker will probably be kinda bagged. Not a good reacher anyway. If you can find a not-too-blownout 5O5 that might be about the best, they sail the closest to the mission profile you're looking for.

How good are you at re-cutting sails? You could start with an old cheap Lightning spinnaker, and take some darts out of it.... starting with 300 sq ft, you should still have plenty when done.

Don't neglect working on how to launch/retrieve/stow the sail. Having a dowsed spinnaker blow half out of the boat and drag in the water is a drag.

I'm a little surprised at the answers about how a spinnaker doesn't significantly increase speed... or speed around the course. In a straight-line drag race, spinnaker already up, on a course or point of sail favorable to the spinnaker, yeah it does. The fact that you spend 2/3 of your time around the course without it, the putting it up, taking it down, the requirements of going on points of sail that are not favorable, etc etc, are why it doesn't help as much as it seems like.

The point is more FUN!!

FB- Doug

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I have seen used spinnakers go up on eBay for $60-100, do you think that would be too cheap for a usable spinnaker?

I don't have much experience with sail cutting, but there is a sail maker at our club that could probably help us if we went that route. 

I have thought about something to store the spinnaker in. Back when the Sidewinders were racing, they used symmetrical spinnakers and a spinnaker sock attached to the fore deck in which the spinnaker could be stored. That's what I plan to do.

martin 'hoff: the asymmetric sounds like a lot of fun and I am sure they are much easier to use, but we are racing in a handicap fleet and the Sidewinder class rules specify a symmetrical spinnaker.

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14 minutes ago, Admiral Hornblower said:

I have seen used spinnakers go up on eBay for $60-100, do you think that would be too cheap for a usable spinnaker?

 

That's about right.

 

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sailmakers...

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1 hour ago, Admiral Hornblower said:

Is there any other place to obtain used spinnakers other than eBay? 

Bacon's

https://baconsails.com/bacon/select_specs_API.php

Lots of sailmakers have a list of used sail inventory... I suspect the profit margin is kinda low, you might do well just calling around by phone... the old-fashioned way!

FB- Doug

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7 hours ago, Admiral Hornblower said:

Is there any other place to obtain used spinnakers other than eBay? 

505 and thistle usenet or forums. See facebook for thistle. See usenet for 505. for the 505 one you want an "old rules" kite. The new ones have a much longer hoist which might drag in the water from your hounds.

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Does anyone here have a Sidewinder that they rigged with a spinnaker? If so, it would be great to see some photos of where you placed the fittings. I'm still trying to figure out what's the right place for the spinnaker sheet blocks, reaching hooks, halyard fittings, and where the uphaul and downhaul should be led to.

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