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Old 29-04-2008, 10:39   #136
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Quote:
Originally Posted by David M View Post
Still confused because VMG is what I am talking about as applied to catamarans and not monohulls. The maximum VMG for most catamaran polars sailing downwind is not 180 degrees but for something less, like 150 degrees for example.

What I am saying as an example is that if you have two identical cruising catamarans sailing towards a leeward mark at 180 dead downwind, the boat at 150 degrees will get there before the boat sailing at 180. Right? That's how it used to work racing Hobie 18's in my experience....you never sailed dead downwind if you wanted to win. I understand more waterline gives you more speed but I am comparing apples to apples with the difference being wind angle.
I do not know about all cats but on my cat that is the way it works actually depending on wind conditions between 145 and 140 degrees
VMG is dotted with a little squire in the polar.
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Old 29-04-2008, 11:13   #137
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Thanks Gideon....that's what I was wondering. The best VMG is not directly downwind for the faster cruising cats unless you can add some sail area.

That's a pretty impressive polar. Boat speed is close to wind speed at around 110 for most wind conditions. At twenty knots of wind speed, they are the same. I would like to see the polars for the 555 when you get it.

Out of curiosity, what is the maximum speed for a boat like this where pushing it any harder is unsafe?
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Old 29-04-2008, 13:46   #138
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Quote:
Originally Posted by David M View Post
Thanks Gideon....that's what I was wondering. The best VMG is not directly downwind for the faster cruising cats unless you can add some sail area.

That's a pretty impressive polar. Boat speed is close to wind speed at around 110 for most wind conditions. At twenty knots of wind speed, they are the same. I would like to see the polars for the 555 when you get it.

Out of curiosity, what is the maximum speed for a boat like this where pushing it any harder is unsafe?
Halo David

I will keep you posted regarding the development of the 555 and the Polars are offcourse a part of this.
I think that wave condition has much to do with how fast you can push your cat.
With the 435 i have done 22 knots and still felt safe with small waves no higher than 2 ft but in high wave conditions I think 15 to 16 is the limit for me. I love my life.
Maximum speeds are not very important but being able to sail fast with just a bit of wind is important , this gives a good average cruising speed./
Today I test sailed with a couple from Switserland and we made 9 knots with 13 to 14 knots of wind speed moderate wave condition up to 5 ft.
The bottom was still dirty after the winter and this makes a difference of 1 knot so being able to do 10 kn I feel is good at an angle of 75 to 80 degrees and 13 knots of wind.
That is the reason we carry much sail with a very light yacht a good SA/DL ratio , reefing is always possible if there is to much wind and we start to reef with 22 knots of wind speed but are already moving close to 17 or 18 knots.
This is why we continuasly are trying to lower the weight of our cats

Greetings and have a good afternoon

Gideon
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Old 30-04-2008, 00:11   #139
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Twice I have had a disaster running dead downwind under kite alone and under headsail alone. I was sailing away from shore and the wind suddenly increased and dropping the kite when screaming downwind under kite alone in 25 knots was a near disaster. We could not pull the sock over it. Releasing the clew caused terrible flogging and then the tack was released and we had this huge flapping sail off the masthead! We started engines, ran downwind flat out and eventually hooked a line and dragged it to the deck. Similarly we tried furling the headsail without any main protection in 35 knots and the load on the furler was too high and the feedline pulled a directing block off before we got the sail in.
I now run at least a triple reefed main in all conditions downwind. It keeps the boatspeed up if I need it and I can centralise the main and remove a reef while tracking along under the kite and then use the main to blanket the kite.
Gavin
(boats were 37ft Crowther supershockwave 'D Flawless' and 'Chaotic Harmony' Catana 42s)
Problems like this don't happen with fully battened sails on unstayed masts. Ever.
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Old 30-04-2008, 08:38   #140
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The best way to resolve performance claims is to have a race, and the best way to guage a boat's relative performance is to see what racing handicap it has been assigned.

I'm down in Antigua for race week Stanford Antigua Sailing Week, and there are three multihull classes with a total of 14 cats racing (out of about 200 boats). There is a separate class for the Gunboats, a racing multihull class (Crepes Wahoo is an awesome tri), and a small cruising class with a Catana 47.

The racers are handicapped by the Caribbean Sailing Association, and the CSA ratings for cats are handled by the French in Guadaloupe. The CSA rating is a time on time factor, so a cat which rates 1.0 should finish in 80% of the time it takes a cat rating 0.8. Looking at the scratch sheet, http://www.sailingweek.com/results/Scratch.pdf, the Catana 47 rates 0.915 without a spinnaker, while the Gunboat 48's rated from 0.989 to 0.924 with a spinnaker and the Gunboat 62 rated from 0.97 to 1.0 with spinakers. Bottom line on this is that the French think a Catana 47 is a bit quicker than a Gunboat 48.

Looking at the results so far, the Catana has not been able to sail to its rating in winds from 10-17 knots, especially when there have been upwind legs. The Gunboats and racing class sailed a different course, so their results are not comparable to the cruising class.

Hopefully more cats will come to more races, and you can mine more useful information out of regatta results. The bareboat monohull class has become very popular in Antigua race week, with over 40 boats racing in 4 classes, and they would welcome more multihulls.
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Old 30-04-2008, 09:26   #141
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The best way to resolve performance claims is to have a race, and the best way to guage a boat's relative performance is to see what racing handicap it has been assigned.

I'm down in Antigua for race week Stanford Antigua Sailing Week, and there are three multihull classes with a total of 14 cats racing (out of about 200 boats). There is a separate class for the Gunboats, a racing multihull class (Crepes Wahoo is an awesome tri), and a small cruising class with a Catana 47.

The racers are handicapped by the Caribbean Sailing Association, and the CSA ratings for cats are handled by the French in Guadaloupe. The CSA rating is a time on time factor, so a cat which rates 1.0 should finish in 80% of the time it takes a cat rating 0.8. Looking at the scratch sheet, http://www.sailingweek.com/results/Scratch.pdf, the Catana 47 rates 0.915 without a spinnaker, while the Gunboat 48's rated from 0.989 to 0.924 with a spinnaker and the Gunboat 62 rated from 0.97 to 1.0 with spinakers. Bottom line on this is that the French think a Catana 47 is a bit quicker than a Gunboat 48.

Looking at the results so far, the Catana has not been able to sail to its rating in winds from 10-17 knots, especially when there have been upwind legs. The Gunboats and racing class sailed a different course, so their results are not comparable to the cruising class.

Hopefully more cats will come to more races, and you can mine more useful information out of regatta results. The bareboat monohull class has become very popular in Antigua race week, with over 40 boats racing in 4 classes, and they would welcome more multihulls.
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Old 30-04-2008, 09:27   #142
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Interesting. Sounds like a good time. I would love to be able to do those races. I think they need some FastCats there as well.
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Old 30-04-2008, 14:25   #143
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I don't know if it is sanding the teak, or all these numbers giving my brain a cramp? This thread has convinced me to strip the boat for my quick excursion to the Bahamas June 1st.

Instead of 3 sets of wrenches I will take one set. Instead of 5 sanders I will take none. Those twenty packs of sanding paper will disappear. All those extra hand compasses will stay home too. I will command everybody to cut their toothbrushes short also. That will surely save some weight. We no longer have bikes aboard. Either motorized, or man powered. I am getting rid of all the weight we had while we cruised, and lived aboard. I think you understand my intentions!

Since a case of beer is over $40.00 in the Bahamas. I can replace the tool weight with beer. I may not sail any faster until the beer is gone, but the sunsets, and my family will be whole lot better looking through those green bottles.
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Old 30-04-2008, 15:00   #144
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Now you are talking
Let me know when that cruise starts

Greetings

Gideon
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Old 28-09-2010, 09:21   #145
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catana versus others cat exept racing cat

I owned a lagoon 470 for nearly 6 years and sailed a lot including atlantic crossing.
I owned a privillége 51 before too
These cats can achieve good daily mileage but sails like "trucks' or RV's and their ability to surf is nearly non existing

it is something very différent on a catana mainly the 430 and 470 for previous models

Now catana is producing boat like the new 42 and the 47 "infused " saving lot of weight.

you will easily gain 3 knots upwind compare to other cats and much more when you surf.A catana can surf at 20 knots...forget that with a lagoon.
More knots will give the ability to générate much more apparent wind and displace the wind more to the bow..mainly when you know a cat is dead stuck when you reach 120° wind angle.

nevertheless a catana is not a racing cat... which requires carbon and no amenities.Catana are fast cruisers.
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Old 14-08-2013, 02:05   #146
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Re: Performance of Catanas

Excellent thread. I know it's old ..... but it is very useful.

The main problem with polars is that reality brings waves. If you are going upwind, waves mean heading off to keep momentum so 35 deg in 20kts has a similar occurance to blue moons .... unless you sail in fetch sheltered waters ..... what bliss!!

I have a heavily loaded Catana 40 ... 1988. It's too heavy, but it's still fun to sail; and it will still sail to windward faster than most cruising monohulls.

I dont race often as there's hardly any other boat out sailing ..... :-)
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