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Old 01-08-2011, 23:11   #1
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How to Get the Most Speed Out of a Sweptback Spreader-Rigged Cat in Light Airs

Hi guys,

We are currently trying to get the most out of our FP Lavezzi 40 sailing downwind at about 130 deg apparent with about 10 to 12 knots apparent.
We don't seem to be able to get any lower without stalling to genoa and loosing a lot of speed.
The swept back spreaders are stopping us getting the main out very far and we have tried traveller up an down with appropriate main sheet but it seems to make little difference.
Any positive suggestions great fully received as we are still learning how to get the most out of new boat?
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Old 02-08-2011, 05:02   #2
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Re: How to get the most speed out of a swept back spreader rig cat in light airs?

You won't get any lower ....130 apparent is already very low. If its speed you're after, this is asymetrical spinaker territory.

Adjusting the main is going to make little difference to whether the genoa draws or not.

A valuable exercise would be to set a waypoint directly downwind and then sail your boat on various AWAs and see which gives you the best VMG to the waypoint. Try this in different windspeeds and you will build up a picture of how your boat performs and its preferred AWAs for different windspeeds.
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Old 02-08-2011, 05:15   #3
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Thanks that sounds like good advice.
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Old 02-08-2011, 06:14   #4
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Re: How to get the most speed out of a swept back spreader rig cat in light airs?

MPS - no main

My 2.2 cents GST included
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Old 02-08-2011, 06:53   #5
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Re: How to get the most speed out of a swept back spreader rig cat in light airs?

If you are going to do a lot of downwind and want to keep it simple... Just stick two genoas on the headfoil and go wing and wing. Won't be particularly fast but it is so easy! We did a circumnavigation like that.

Just noticed your list of other boats... You probably really do want to go fast so just ignore my suggestion
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Old 02-08-2011, 09:25   #6
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

Bewitched said it exactly.
You will have better boat speed and a smoother ride as well.
Use an assymetrical chute, main and then occasionally gybe downwind.
We do that and leave wing and wing sailors in the dust (well, WET dust).
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Old 02-08-2011, 09:35   #7
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

Yup, genoa's don't work well with the wind at or behind the beam. Cruiser's who are shy about spinnakers (and the like) should talk to a good sailmaker about a desireable headsail for light off-the-wind work. Amazing things can be done.

No modern boat is happy with the apparent wind at 130. Try to believe that sailing higher will get you there faster and more comfortably. In the tropics there's an added benefit to sailing higher: more apparent breeze thru the cockpit and cabin. Ahhh.

Oh, and one more thing, sailing high across the wind, even though one seems to be heading in the wrong direction some of the time it does allow the clever tactician to choose a course that may encounter more wind later...like an evening shore breeze...or a friendly squall. DDW folks are stuck with what they have or what may eventually overrun them.

[Wing-on-wing DDW fans please ignore.]
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Old 04-08-2011, 01:41   #8
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Thanks for all the great advice, I thought I was going to get smashed on this post.
Going from an Etchells to a cruising cat is doing our heads in trying to work it out, it is so different.
Especially using a plotter which tells you the ugly truth about your VMG.
I think the screecher order will be confirmed shortly.
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Old 04-08-2011, 01:52   #9
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Re: How to get the most speed out of a swept back spreader rig cat in light airs?

Quote:
Originally Posted by Factor View Post
MPS - no main

My 2.2 cents GST included
+1
Cruised many many miles in this fashion with shade cover in place and expensive mainsail zipped up in boom bag.

Actually, I had a large,cheap symetrical kite with squeezer sock, attached to a central prodder, not an mps at all, but it still worked a treat.
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Old 04-08-2011, 02:03   #10
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

AWA - ??
VMG - Velocity made good. The speed of the boat toward the mark as opposed to the speed toward where it is heading
MPS - ??



I think I get the idea...

(Novice in training)
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Old 04-08-2011, 05:47   #11
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

AWA + Apparent Wind angle, the wind angle the boat is seeing
MPS is multipurpose spinakker - an asymmetric sail (a traditional spinaker is symmetric) designed for wind behind the beam mostly and lightish apparent winds - mostly
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Old 04-08-2011, 06:03   #12
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

Thanks for that Factor - lots to learn. Cheers
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Old 04-08-2011, 19:43   #13
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

I'm with the spinnaker and head up to VMG (ish) folks in the light stuff. The apparent wind can move around a lot though which can require close attention. Running deep with just the spin is slow for us (we run a masthead kite) but can be very pleasant and relaxing. Dropping or deeply reefing the main makes the spinnaker much more forgiving. When running in squally conditions or at night we often sail with a deeply reefed main and spinnaker. When it gets blowy and the spin seems a bit too ambitious we do the DDW thing with just the jib trimmed to outboard sheets. Really good outboard sheeting options are one of the nice things about multis.

Tom.
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Old 04-08-2011, 20:49   #14
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

+1 on using outboard sheeting points. Makes a huge difference to our speed reaching or running. I have an extra "sheet" I use to tweak the sail shape right up to close hauled. Also helps keep the headsail working a great deal better for sailing DDW, with either just the headsail or wing-on-wing.
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Old 04-08-2011, 22:39   #15
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Re: How to Get the Most Speed Out of a Sweptback Spreader Rigged Cat in Light Airs ?

The big chute is fun to fly but if you want to go fast....You need to draw everything in and make it flat, using the sails just like you were going to weather. Pushing the sails out means you are using them like a square rigger...you press to approach a few knots under the wind speed. Hauling them flat and tight means they act like an airfoil and you can get the effect of your speed adding to the wind speed, just like going upwind. Try it. You can do this in a cat easily (requires gybing). Watch the video of the America's Cup.

Just like that except I can't go near as fast!
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