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Old 12-05-2013, 18:04   #151
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Re: What are the Slowest Cats?

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Originally Posted by Wannabe-007 View Post
Surely if anyone could be bothered, it would be possible to use polars combined with real (or imaginary) weather data, and a course, to plot out a handful of competing boats and run a theoretical race...

Its not hard evidence, but its indicative at least.

Any volunteers?
I never saw a polar for my Gemini.
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Old 12-05-2013, 18:49   #152
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Re: What are the Slowest Cats?

IME, most production boats will not sail to their polars. Very few boats have generated their own accurate polars. I think that this is a useless approach to the issue.

In the real world there are some fast cats and some slower ones... just like monos. Sometimes this is due to design, sometimes to loading, sometimes to sail quality, and sometimes to skipper skills. Pretty hard to make generic statements that mean anything.

I enjoy occasionally sailing past a cruising cat, and sometimes they seem to enjoy blowing us away. The latter makes me grumpy, but what the hell, some of them are pretty quick!

Why are we worrying about this?

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Old 13-05-2013, 10:32   #153
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Re: What are the Slowest Cats?

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Why are we worrying about this?

Cheers,

Jim
Because everyone knows the consensus is cats are slow and can't sail to windward.

And that the Endeavour cat is a real slug. Again the consensus.

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Old 13-05-2013, 11:32   #154
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Re: What are the Slowest Cats?

Like I mentioned, any one who wants to debate general performance characteristics between monos and cats get to choose the boat they measure against.

The rest of us can just sit back and watch (and laugh).

I suspect we would see a lot of Warram's racing against Out Islands, or Packet Cats against Formosas. Doubt we are going to see Wallys against Outremers, so we can watch the AC trials with all the time we will have...

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Old 13-05-2013, 11:59   #155
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Re: What are the Slowest Cats?

Wharrams thrashing it

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Old 13-05-2013, 12:20   #156
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Re: What are the Slowest Cats?

Depends on what you mean by slow. Basically it's just a function of waterline length. A heavy 40 ft waterline will go as fast as a light one (Until we get beyond displacement hull function) However in a drag race, a light one will accelerate faster to hull speed, so it will cross the finish line sooner... although a heavy one with a huge amount of sail may do the same thing!
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Old 13-05-2013, 12:29   #157
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Quote:
Originally Posted by Cheechako View Post
Depends on what you mean by slow. Basically it's just a function of waterline length. A heavy 40 ft waterline will go as fast as a light one (Until we get beyond displacement hull function) However in a drag race, a light one will accelerate faster to hull speed, so it will cross the finish line sooner... although a heavy one with a huge amount of sail may do the same thing!
I'm afraid cats and tri's fall outside the average boat shape assumed by the waterline length rules of thumb. A small Tornado cat will outsail a 60' boat without planing...
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Old 13-05-2013, 12:59   #158
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Re: What are the Slowest Cats?

I think Cheechako was only discussing cat vs. cat relative to which is slower.

Even there, it is much more than waterline length for speed. Waterline shape, submerged hull, B/L, rocker, and other factors like whether chines submerge at speed make differences to top speeds and when they can be reached.

So, it is much more than waterline that determines top speed given a finite sailplan and rig. Our boat is 1-1.5kts slower on all points of sail and in all wind conditions since we put everything on it and left cruising, compared to when it was pretty stripped and sailed recreationally. The only difference is weight and submerged hull volume.

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Old 13-05-2013, 13:07   #159
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Re: What are the Slowest Cats?

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I'm afraid cats and tri's fall outside the average boat shape assumed by the waterline length rules of thumb. A small Tornado cat will outsail a 60' boat without planing...
Hah, not without planing it wont! a Hobi cat will outsail a 60 ft boat... but it will be planing! As will a wind surfer...
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Old 13-05-2013, 13:13   #160
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Re: What are the Slowest Cats?

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Originally Posted by Therapy View Post
Because everyone knows the consensus is cats are slow and can't sail to windward.

And that the Endeavour cat is a real slug. Again the consensus.

I absolutely agree. The thing is built like a tank and oddly kind of looks like one. It has terrible sail controls, a fixed boom vang, and no traveler. There is virtually no way to adjust sail twist in the main. It has a big flat area at the front of the bridge deck to slow it down everytime it hits a wave. It has a relatively small sail area for a boat it's size and it does not have a dagger board to help it point. Definitely a slug, yet it beat those other cats in real time. Bizzare! I can't explain it, I just report it. Frankly it makes no sense to me.

Oddly on my way to the Abacos last week my nice broad reach turned into a beat after passing under some clouds that had to some sort of unforecast frontal boundry as the wind went from aboyt 210 to 310 in about a half mile. I am unaware of any polars ever being done for an Endeavourcat, but I have my windex set at 65 degrees and when I pulled everything in as tight as I could make it I was sailing at only about 4 knots into about a 10 knot wind. The wind vane at this time was inside the flags. So this thing was still sailing at 30 degrees apparent or less. I fell off about 20 degrees and accelerated to about 6.5 knots, with the vane just a bit outside of the flags. I guess I found the front of my polar plot.
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Old 13-05-2013, 13:59   #161
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Re: What are the Slowest Cats?

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Originally Posted by Cheechako View Post
Hah, not without planing it wont! a Hobi cat will outsail a 60 ft boat... but it will be planing! As will a wind surfer...
Hobie Cats are displacement. Period. Hobies have asymmetrical hulls, they cannot possibly plane.

In fact, neither does the Tornado.
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Old 13-05-2013, 14:14   #162
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Re: What are the Slowest Cats?

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Originally Posted by Captain Bill View Post
I absolutely agree. The thing is built like a tank and oddly kind of looks like one. It has terrible sail controls, a fixed boom vang, and no traveler. There is virtually no way to adjust sail twist in the main. It has a big flat area at the front of the bridge deck to slow it down everytime it hits a wave. It has a relatively small sail area for a boat it's size and it does not have a dagger board to help it point. Definitely a slug, yet it beat those other cats in real time. Bizzare! I can't explain it, I just report it. Frankly it makes no sense to me.

Oddly on my way to the Abacos last week my nice broad reach turned into a beat after passing under some clouds that had to some sort of unforecast frontal boundry as the wind went from aboyt 210 to 310 in about a half mile. I am unaware of any polars ever being done for an Endeavourcat, but I have my windex set at 65 degrees and when I pulled everything in as tight as I could make it I was sailing at only about 4 knots into about a 10 knot wind. The wind vane at this time was inside the flags. So this thing was still sailing at 30 degrees apparent or less. I fell off about 20 degrees and accelerated to about 6.5 knots, with the vane just a bit outside of the flags. I guess I found the front of my polar plot.
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Old 13-05-2013, 19:50   #163
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Re: What are the Slowest Cats?

The whole idea of a multi having faster speed potential than a (non planing ULDB) mono is because they can exceed hull speed without planing.

Hull speed is the function of the size/length of the wave a hull makes compared to the length of the hull. To exceed this speed the boat can rise over the wave, which we call planing. Or the other way is not to produce a large wave that prevents the hull from being able to pass it. The only way to do this is to have a very narrow light weight hull.

Elite paddlers can push their kayaks at roughly double hull speed for a sprint due to the long narrow and light weight boat. The shape does not generate a significant bow wave which a heavy boat could not overtake. They are certainly not planing and at 11K they are faster than 99% of the forums cruising boats mono or multi.

Quote:
For the short 200 m sprint 34 seconds is world champion class time moving at 13 mph achieved by one of those Hungarian clones of Arnold Schwarzenegger sticking out of these kayaks. That is twice the 6.35 mph theoretical hull speed of the around 17 ft K-1 kayaks.
Some cats are narrow and light so they can easily surpass hull speed due to only small waves being produced, some are heavy with wide hulls so they struggle to pass hull speed due to a large wave train like a mono.

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Old 14-05-2013, 00:43   #164
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Re: What are the Slowest Cats?

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Originally Posted by Cheechako View Post
Hah, not without planing it wont! a Hobi cat will outsail a 60 ft boat... but it will be planing! As will a wind surfer...
Incorrect. Edmond Bruce discovered that above a LWL:BWL ratio of around 8:1, theoretical hull speeds cease to apply. Bow wave propagation is reduced to the point it is no longer a limiting factor.
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Old 14-05-2013, 04:48   #165
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Incorrect. Edmond Bruce discovered that above a LWL:BWL ratio of around 8:1, theoretical hull speeds cease to apply. Bow wave propagation is reduced to the point it is no longer a limiting factor.
See, this is the mistake I keep making... I assume people all know these basic things but here it shows again that only cat sailors know this but mono sailors are ready to voice their wrong opinion as fact and then we get the whole yes-no fight again over something where opinion doesn't count really.

I am a mono sailor, how come I know this?
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