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Old 02-01-2008, 08:33   #1
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Cruising Cat Rigs

There are several different ways that cruising cats are rigged and I am trying to better understand the pros and cons of the different rig designs especially as it relates to downwind sailing and mast strength.

Many Lagoon Cats have only one side stay on each side and one tripod style spreader rig.

Switch 55 and Dolphins have two side stays on each side, one lower and one upper. They also have a traditional spreader rig and not the tripod spreader like on many cats.

Outremers have one or two side stays, tripod spreader rig and running back stays on each side.

Catana cats have one side stay on each side and a tripod spreader rig.


So here are the questions:

Why did the newer designed cats move away from running back stays?
Are running backs better (stronger) for downwind sailing and mast strength and do they allow you to fully drop the main when flying a chute?

How are the tripod spreader rigs better or worse than the traditional spreader rigs. It seems that some manufactures are trending away from the tripod spreader rigs now yet many boats have them.

My cat manufacturere Dolphin advises to NEVER fly 100% of Genoa without the main flying yet I know other cat owners have done this without problem.

My manufacturer also advises to not fly a spinnaker without the main up
but I know that many Catana owners fly big spinnakers with two reefs in the main and then sheet down hard on the topping lift as kind of a make shift back stay and they only have two side stays while doing this. Does sheeting down the topping lift hard really act well as a back stay? Does this risk losing the rig? Do I risk my rig falling by flying a chute without the main? You get much more power from the chute with the main reefed down or dowsed.

I am aware that cats like MAXING OUT who is a member of this website sailed his Privalige cat around the world with two head sails and no main and he had no trouble with the integrity of his rig yet this is not supposed to be good for the rig.??

Fro those of you who have more expertise in the pros and cons of cat rigs and how they hold up under different circumstances such as down wind sailing, wing and wing, genoa only situations, and spinnaker flying it would be great to hear your thoughts on this subject.

Keegan
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Old 02-01-2008, 09:25   #2
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CORRECTION: I called the side rigging ""stays" in the above post but meant shrouds. Cruising cats either have one or two shrouds on each side typically.

Keegan
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Old 02-01-2008, 10:41   #3
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Hi Keeg - Happy New Year!

Good questions. Full answers probably require the insights of a rig designer. The mast lengths, material and section modulus and intended sail plans determine what's needed to hold the whole thing up. And there are probably many acceptable solutions for each set up.

Quote:
Originally Posted by Keegan View Post
My manufacturer also advises to not fly a spinnaker without the main up but I know that many Catana owners fly big spinnakers with two reefs in the main and then sheet down hard on the topping lift as kind of a make shift back stay and they only have two side stays while doing this. Does sheeting down the topping lift hard really act well as a back stay? Does this risk losing the rig? Do I risk my rig falling by flying a chute without the main? You get much more power from the chute with the main reefed down or dowsed.
I'm one of those guys who likes to fly the big spi w/o the main up. I've also done it with a dbl reef main. High enough on the wind and the full main can be used. But I wouldn't use just the spi if it was 20+ w/o also cranking down some on the main sheets to use the topping lift (or main halyard re-located to further aft on the boom) as a pseudo backstay. I don't know what the real risk of losing the rig might be nor what wind speed becomes chancy, but why not take the precaution? I changed out my topping lift with a lower stretch, stronger line just for this purpose.

So, if Dolphin advised you never to fly your chute or genny w/o the main, I bet they are being understandably conservative. After all, you would go downwind with just the main lightly sheeted, right? There must be a threshold where it starts to get dicey, but I gotta believe your boat could easily handle well into the 20s without a significant risk. Ask Phil.

BTW, the Catana carbon rigs have traditional spreaders (non-tripod) with single side stays.

Dave
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Old 02-01-2008, 13:28   #4
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If the maker requires you fly the main with the jib/kite they must feel the spar needs the leech to support the panel. As Dave said, contact the maker and review exactly what sail combination you can fly and when you need to watch out.

It really does not matter if you have spreaders or diamonds to support the panel. The spar maker designs the length of the unsupported panel and the boat designer determines the landing point for stays.
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Old 02-01-2008, 13:50   #5
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Hallo Keegan

I had not seen your post but here are my idea,s on pro,s and cons for rigs on cats.
We at african cats give our customers the choice for having running backstays or not , in any case the attachement points are there so in case of an emergency with a side stay these points can be used in combination with the topping lift line that in our case is also made of dyneema with a working load strenght of 6000 kilo or 13200 lbs.
The reason for not standard installing running back stay,s although it is a stronger solution for downwind sailing, is the extra work involved and the location on our cat where it would sit in front of the side seat and in the walkway.
I cannot speak for the Dolhin 460 but in our case we have made the strenght of the side stays and the chainplate connection so strong that even with 35 knots of wind we can still fly the spinnaker or gennaker without having to raise the main. I have sailed both our prototype and the first production 435 well over 20000 NM with just the spinnaker or the gennaker in wind conditions ranging from 6 up to 35 knots ( downwind with a speed of 17 to 20 knots) It must be a precaution from the Dolphin manufacturer to advise you to raise the main ( Partially ).
I do not understand why the manufacturer advises never to let out your genoa without the main up.
The advantage of having 2 side stays on each side is extra safety , a bit of weight saving and another adjustment possibility.
On our prototype of the 435 we had this solution, the disadvantages did outweight the advantage,s. the walkway interference for the inner side stay made us change this.In order to save weight we have changed the side stays to Dyneema , tripod spreader rigs are not better or worse then non spreader rigs it is used to make the mast stiffer/stronger and it allows to make a prebend without inner side stays.
I guess it is all a matter of choice and cost at the end of the day.

I hope I have helped you with this explanation

Gideon Goudsmit
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