So How High Will a Cat Point?

[Joli]

I have friends that go "reaching".

Chris, where are you and the family going this weekend? His reply, "any destination that is a reach".

Originally Posted by Mark Johnson

I don't know... perhaps it's the Bermida triangle or something, but we go to windward from A to B, then turn around, and the sail back is ALSO to windward! Go figure.

Over the last 15 years, we so seldom sail a passage "off the wind", that I remember each one. I think that crossing oceans with the trade winds would be totally different story...

Mark

[Southern Star]

I suspect that Barnakiel's post was either in gest, or an effort to ramp-up the theatrics on this thread. Barnakiel, I am pretty confident that you do not believe that multis are twice as fast as monos (nobody has suggested that, nor is such an 'opinion' in any way relevant to this thread). I also think you know that Catanas are reputed to be pretty well designed cats, even if some believe that the new ones are a bit overweight.

Lets face it, for most cruising cats, windward performance is not their best point of sail. Nevertheless, there are some that are astonishingly effective to windward. What the prospective purchaser has to do is come up with his/her own set of priorities. A boat with long LAR's keels, huge interior volume, raised helm stations, a high CG and correspondingly higher windage won't be particularly effective to windward. That is, however, a compromise that some are prepared to make for the benefits in terms of accomodation, cost and simplicity of operation. For others it is not.

If you want excellent windward performance you can get it in a multi, but it will come at a cost elsewhere. If you are prepared to compromise to soime degree on windward performance in exchange for some other benefits, you can choose that route. What concerns me is that the suggestion here seems to be that all multihulls are alike in this regard -and that is akin to saying that all monoihulls perform to windward like a Westsail 32.

Brad

[tsmwebb]

Originally Posted by Southern Star

...
If you want excellent windward performance you can get it in a multi yacht, but it will come at a cost elsewhere. If you are prepared to compromise to soime degree on windward performance in exchange for some other benefits, you can choose that route. What concerns me is that the suggestion here seems to be that all multihulls are alike in this regard -and that is akin to saying that all monoihulls perform to windward like a Westsail 32.

Brad

Right on.

There also seems to be some confusion about what it means to be weatherly. While apparent wind angles tell an interesting story they are only part of the whole picture. In the end the boat that gets to the weather mark first is the more weatherly. At the pointy end of the performance scale multis greater than about 15' are significantly faster to the weather mark than monos of the same length in all but drifting conditions. At the slow end of the scale I believe monos are generally more weatherly than comparable multis but the further from the all out, no holds barred end of the performance scale one gets the harder it gets to determine what boats in what trim are "comparable". Still, there is a cross over point. IMO, there has been a trend in modern racing keel yachts towards faster designs and some trickle down into the racer/cruiser market that has not been matched by the cruising multi market in general. So, while ultimately cats can be more weatherly than monos my feeling is that by and large in the fleets that exist today they are not compared to monos in similar cruising service. As SS suggests this is purely a result of the design and construction choices.


Tom.

[Dragon Lady]

Having an Etchells mono hull I was not expecting much windward performance from our Lavezzi 40 cat, but I've been surprised at how high it will track nicely to windward. The wind indicator showed 30Deg apparent at about 6.5 knots.
I thought the gauge must be out of calibration but maybe not?

[barnakiel]

Originally Posted by GordMay

Can you (or anyone) explain why that would (or would not) be?

A well designed cat is well designed. Most monos are designed.

The well makes for the difference.

Hope this briefly explains. And, if it does not:

1) I might be talking nonsense (am I?) - this may be due to having far more experience sailing monos. I have sailed an Opti, I have sailed an AC, and some 200+ other designs of mono-hull in between. However, my experience with cats is limited to Hobbie, Nacra, Schionning and Catana likes - probably fewer than 20 designs altogether. Thus, my opinion may be biased - because I do have to few multis under my belt.

2) Maybe, on the other hand, the explanation is that modern day multis are modern day designs where designers had both more real life data to use and the help of computer assisted design processes? Most monos seem to be designed to the rule 'let's make it like this, because this is how my father built boats' - a good rule, if less than conductive to performance.

3) Maybe, again, the point is that so many multi designers are ex-racers or performance oriented minds?

Good question Gord, THX, you got me wondering.

barnie

[atoll]

denile is not a river in egypt,face it guys cats going to weather in any thing above 30 knots in the open sea is very stressfull,not only to the skipper.

performance or not catamarans were not designed to be able to withstand what a mono can going to weather in all conditions.

some really fantastic designs out there,but if you want a 4x4 the technology is in monos for wind ward performance.

[thinwater]

Common guys, let them feel good about the ONE thing monohulls do well. Be nice. Pretend windward ability is everything.

[barnakiel]

Originally Posted by Southern Star

I suspect that Barnakiel's post was either in gest, or an effort to ramp-up the theatrics on this thread. Barnakiel, I am pretty confident that you do not believe that multis are twice as fast as monos (...)

Yep. Sometimes it is hard to say which part of my post is factual and which confabulatory. Frankly, having re-read my post above I am lost and seriously worried that I got it all so perfectly mixed together that I might have been both serious and dramatic - throughout.

I believe hull dynamics explains part of why cats are faster than monos. Hull speed is related to hull elongation. Turbulent flow is related to elongation. Drag is related to turbulent flow. Speed is related to drag, et cetera.

Having to drag along 50% of extra weight (in the very venerable, but little useful, speed-wise, form of the ballast) explains a bit too. The term 'ballast' is at least self explanatory, and loaded. Imagine - what speeds we could achieve in our lives, if not for the ballast of our preconceptions!

BTW I have just seen a newish Lagoon - ever wondered why the main has a square top? Well, I read Marchaj's books when I was a kid, then I tried at least not to lag behind too much. So the square topped main may explain its bit too. Will I ever see a HR with a square topped main? No? Why?

All the little, and not quite so little, pieces add up to the fact that multis are faster than monos.

Are they 2 times faster? Wait: let's have a look at the opening of this post!

Seriously though: off course my post was a bit theatrical! If anybody got mislead in a bad way, then accelerated and ended up on the rocks ... upsss ;-)))

From aboard a "slow" mono, dreaming of a fast multi ;-) (50% kidding)
Hugs to all ya (100% seriously)

barnie,
the sea monster

[tsmwebb]

Originally Posted by atoll

denile is not a river in egypt,face it guys cats going to weather in any thing above 30 knots in the open sea is very stressfull,not only to the skipper.

performance or not catamarans were not designed to be able to withstand what a mono can going to weather in all conditions.

some really fantastic designs out there,but if you want a 4x4 the technology is in monos for wind ward performance.

Upwind in hard conditions is miserable on any sail boat.

YouTube - Rough Sailing

YouTube - ultimate sailing

Building a tin mono and decking it out with roll bars, fancy netting and baggywringle may look like the be all and end all of toughness. But design is more than skin deep. A fiber and plastic boat with any number of hulls can be made arbitrarily tough and seaworthy.

Tom.

[atoll]

Originally Posted by tsmwebb

Upwind in hard conditions is miserable on any sail boat.

Building a tin mono and decking it out with roll bars, fancy netting and baggywringle may look like the be all and end all of toughness. But design is more than skin deep. A fiber and plastic boat with any number of hulls can be made arbitrarily tough and seaworthy.

Tom.

looks like a mono with outriggers,and no ballast?

[tsmwebb]

Originally Posted by atoll

looks like a mono with outriggers,and no ballast?

Yes... And a helicopter looks like a space shuttle with extra blades.

Here's one that looks like a monohull with an extra hull and no ballast.

YouTube - Playstation in BIG WAVES

Tom.

[barnakiel]

Originally Posted by atoll

(...)

performance or not catamarans were not designed to be able to withstand what a mono can going to weather in all conditions.

(...)

Many were not.

A cat will normally bear off, bang less, sail twice as fast and get to the upper mark in 30% less time than a mono.

But the question (originally) was not 'in all conditions'. It was 'how high'. And the OP (I think) added 'well designed'.

I will tell you one thing, mates, a poorly designed cat will not point, neither will a poorly designed mono.

PS I think I have seen polars for some cats starting at 40 degs, not bad. Alinghi pointed below 20, but then again Alinghi prove a pig, although not vis-a-vis a mono, somehow.

b.

[tsmwebb]

Originally Posted by barnakiel

Many were not.

A cat will normally bear off, bang less, sail twice as fast and get to the upper mark in 30% less time than a mono.

But the question (originally) was not 'in all conditions'. It was 'how high'. And the OP (I think) added 'well designed'.

I will tell you one thing, mates, a poorly designed cat will not point, neither will a poorly designed mono.

PS I think I have seen polars for some cats starting at 40 degs, not bad. Alinghi pointed below 20, but then again Alinghi prove a pig, although not vis-a-vis a mono, somehow.

b.

FWIW, I think A5 sailed downwind at AWA's < 40... I'm not quite sure how to deal with that in the context of the OP's question... I mean if VMG downwind > TWS and AWA < 40 what does that say about "pointing"? Perhaps the original question could be more meaningfully dealt with in terms of efficiency or VMG's?

Tom.

[atoll]

what i dont understand is why it is nessecery to post videos of multi million dollar,light weight,state of the art multis to prove your point that cats can actually go to windward,surely there must be something on utube of a production cat going to windward at say 45 degrees or is this a myth?

this one goes to windward really well.

YouTube - Unusual Catamaran with Wind Turbine Propulsion in Guernsey

[gbanker]

here is an interesting video:

YouTube - GUNBOAT...

.

the catamaran is not pointing quite as close to the wind as the monohull but guess which one would be first around a race course?