Why Do Catamarans Motor Nearly 100%

[Polux]

Originally Posted by four winds

...
No need for looking to upgrade. But if I ever win the lottery there is little doubt I'll replace them with a Sig45 and a Discovery 57. Dream on I guess, but I have free time for dreaming; and sailing.

Change that Discovery by the new X6 and invite me for a ride on both boats
X6

[44'cruisingcat]

Originally Posted by Polux

Maybe you don't remember the conditions were the video was made. Look at it again:

There is almost no waves and the sea is not coming from the bow, but from the side, and that suggest a current. There would not be any spray on those conditions no matter the type of boat used.


You seem to make any discussion a personal one as if this discussion, about the poor upwind performance of condo cats, had to do with your boat, or my boat.

Contrary to you I rarely talk about the performance of my boat and try to use reliable data from other boats and other sources when comparing different types of boats simply because one tends to be biased regarding his own boat. Anyway your boat is a 44ft and mine is a 41ft so I don't see any point in what regards comparisons.

But since you insist in comparing the performance of your boat upwind, even with non controlled data (the sea direction seems to indicate that there is a current), lets have the data your instruments show even if you are using SOG, since you say that the log is unreliable and gives higher speeds. I have looked carefully at the movie:

You have an inside wind instrument that is set for true and gives a true wind of 11.9K. The SOG on the plotter oscillates between 8.7 and 8.5K and the apparent wind angle at the beginning of the video marks about 27º and at the end of the movie about 30º. Let's consider an average apparent wind angle (28.5º) and average SOG speed (8.6K) and the true wind that is marked on the interior wind instrument (11.9.). That gives a VMG of 5.7K with a true wind angle of 48.5º.
Apparent Wind Calculator | Hyde Sails Direct
In what concerns upwind performance the numbers that count are not those of the pointing angle or speed but the VMG upwind, that consider both parameters. Regarding performance cruisers the size of your boat, well a little smaller, we can look at the performance of the Landmark 43, like your own boat, not a carbon boat, but one with performances above average:

with 12 k wind the boat makes a VMG of 5.8 with a true wind angle of 36.9º.

The data is not coming from Polars but from ORCI rating files and you can be sure that if that data was not possible to achieve under good conditions it would be already modified, since there are several Landmark 43 racing and all the owners want those numbers as low as they can possibly be, to have better racing results. The Landmark 43 is a very competitive boat in ORC rating and that means that those numbers are for real.

But I still think that there is some current helping that SOG speed on your boat.

Since you like to compare your boat with monohulls we can extend that comparison a bit further and look at another video of yours were your cat is making with 11k true wind 8.9/9k speed at 120º true wind angle.

I agree that this angle is more favorable for a cat than for a monohull but even so let's compare with the performance of the smaller Landmark 43 at that angle and since I have not data for 11k wind, with 10 and 12k true wind: 12k TRW - 9.26K, 10K TRW - 8.60K.

But I still believe that for looking at the general performance of cats versus monohulls, in what regards downwind sailing and on passage, there is no better place than the ARC. We can discount the two extreme performances, a extremely good one and a extremely bad one and we get an average of what the boats are able to do with average crews, while doing an Atlantic crossing.

Wow. I guess I should be flattered. You've compared my overloaded, cheap and worn out sail equipped, CRUISING catamaran, sailing on autopilot, to a high performance cruiser/racer, who's polars would have been measured with brand new, high tech sails in perfect conditions, lightly loaded, skilfully crewed, and found they manage a VMG of ONE TENTH OF A KNOT faster upwind!

And to find that one tenth of a knot advantage, you've used the lowest speed that briefly flashed up on my plotter screen, not the more usual 8.9 -9 knots.

WELL DONE!

And your claims to being unbiased are absolutely laughable. Just laughable. The best, most positive thing you've said about a catamaran, or any multihull, is that you might consider one if they were cheap enough.

Even when you go on about your precious ARC, you mention how a Lagoon 380 beat some performance cat's. But presumably it didn't also beat some mono's? Some supposedly fast ones maybe?

I don't claim to be unbiased. I've owned a mono, cruised on one, lived on one, raced them. And done the same with cat's. I have a bias, for sure. But one based on real-life experience of both types.

[monte]

Im not sure about manufacturers polars. Im not even sure what they are for our lagoon 400 but upwind or downwind is a sweet ride. Heres some recent snaps of an upwind sail, make of the data what you will..

Average SOG was around 7K with tacking angles close to 90 degrees, into a 1K+ current.
TWS here should be closer to 18K but fluctuates with swell etc.

Log showing 8K through water and opencpn showing 6K SOG. Some current.....

[ArtM]

Funny, I see ALL kinds of sailboats motoring ALL the time, and very often wonder why they are not sailing.

I think the answer is that, most of the time, the people on board are just too lazy or too impatient to fool around with sails when the motor is there, it's already running, and the motors are on.

For the vacationers, I agree that most of them are probably not very experienced sailors and are more interested in the wide decks and spacious cabins that a Lagoon or similar Cat offers. They have somewhere to go, and they are on their way there.

[ArtM]

I see this is now a cat vs monohull performance thread. Let me make it less interesting

- Cats perform better on some tacks, monohulls perform better on others
- It makes no sense to compare a 45 foot luxury catamaran against a 28' racing sloop
- I don't have the proof myself (though it is probably in the above posts), but I do believe that a luxury catamaran will noticeably outperform a similarly appointed and capable fat-bottomed luxury cruising monohull, and do it better.

[Boatguy30]

Spent the last few days mostly sailing the ICW south from St Augustine. No other "sailboats" with even a scap of sail sited. Did get in a bit of an awkward situation when I overtook a "sailboat" right at a bridge and had no choice but to pass them as we went under the bridge heading DDW in 20 knots. About to catch the tide and the NE 15-20 down to Titusville. Will have to break out the Honda genie to top up the batteries a bit tonight.

[beiland]

Originally Posted by Polux

If I had an unlimited budget this one would be on my short list:

Thanks for bringing that SIG45 subject up again. I hadn't looked at it in a long time.

The concept of 'blister cabins' reminds me of one of my old favorites of the Stiletto cat line, the Stiletto 30.

I think I have a use for incorporating this design concept into a new design,... less performance oriented than the SIG45

[Polux]

Originally Posted by monte

Im not sure about manufacturers polars. Im not even sure what they are for our lagoon 400 but upwind or downwind is a sweet ride. Heres some recent snaps of an upwind sail, make of the data what you will..

Average SOG was around 7K with tacking angles close to 90 degrees, into a 1K+ current.
TWS here should be closer to 18K but fluctuates with swell etc.

Log showing 8K through water and opencpn showing 6K SOG. Some current.....

My experience of sailing side by side with condo cats (without dagerboards) tell me that they cannot make a tacking angle of 45º and in fact you show bigger angles on the plotter. The angles are far from 90º, maybe 80º and that will make a tacking angle of 55º. A good monohull with that wind will make 10 to 15º better.


My experience, sailing side by side with monohulls is consistent what those Polars show, regarding the potential of that type of boat upwind.

Regarding the instruments the pointer shows a bit over 30º apparent wind angle, there is a central figure that shows 20.5K? apparent wind speed and a boat speed of 8K. that gives a true wind angle of 49.2º that is consistent with those tacking angles.

It is the first time that I see contested that the upwind ability of a condo cat (including Lagoons) is not a poor one if compared with the one of a modern monohull. I thought that was common knowledge and it is a well established fact.

Some condo cats are better then others, particularly the ones that have small keels but the performance cannot be similar to the one of a sailboat with a swallow but deeper keel, much less to the one with a deep keel.

The Dragonfly 35 is a very fast performance trimaran with a very good upwind performance to a multihull (it has a central board).

Here you have one, carbon sails and all being beaten upwind by a 37ftt monohull and not even a new design (both boats are racing):

https://www.youtube.com/watch?v=I0IqQ7kaDQs

[Polux]

Originally Posted by beiland

Thanks for bringing that SIG45 subject up again. I hadn't looked at it in a long time.

The concept of 'blister cabins' reminds me of one of my old favorites of the Stiletto cat line, the Stiletto 30.

I think I have a use for incorporating this design concept into a new design,... less performance oriented than the SIG45

Yes, I like very much the Stiletto, a great design ahead of its time but i don't think that most that buy a cat, buy it for the performance, otherwise the most common type by far would not be heavy condo cats with huge free-board and without dagerboards. And I don't think the tendency is diminishing but increasing, now to motorcats also.

A bit like on monohulls, it is hard for me to understand why people buy fatter boats just to have a bit bigger interior space and a bit bigger headroom. It seems that the small advantage does not pay off in lesser sailing ability or beauty...but that is what most sailors want, no matter my opinion. Reality rules

[admiralslater]

Originally Posted by Polux

My experience of sailing side by side with condo cats (without dagerboards) tell me that they cannot make a tacking angle of 45º and in fact you show bigger angles on the plotter. The angles are far from 90º, maybe 80º and that will make a tacking angle of 55º. A good monohull with that wind will make 10 to 15º better.


My experience, sailing side by side with monohulls is consistent what those Polars show, regarding the potential of that type of boat upwind.

Regarding the instruments the pointer shows a bit over 30º apparent wind angle, there is a central figure that shows 20.5K? apparent wind speed and a boat speed of 8K. that gives a true wind angle of 49.2º that is consistent with those tacking angles.

It is the first time that I see contested that the upwind ability of a condo cat (including Lagoons) is not a poor one if compared with the one of a modern monohull. I thought that was common knowledge and it is a well established fact.

Some condo cats are better then others, particularly the ones that have small keels but the performance cannot be similar to the one of a sailboat with a swallow but deeper keel, much less to the one with a deep keel.

The Dragonfly 35 is a very fast performance trimaran with a very good upwind performance to a multihull (it has a central board).

Here you have one, carbon sails and all being beaten upwind by a 37ftt monohull and not even a new design (both boats are racing):

I will say from the out set that I am a cat guy. That video demonstrates one of the every interesting differences between multihulls and monohulls in that in light winds , and this is a generalization but in light winds equal boats will line up this way tris are are faster than cats and mono hulls are faster than both. I have raced dozens of all types and it has always been this way. I think the inertia of the mono hull works in its favour once the boat gets to speed. With cats and tris it is simpler as I believe it is a wetted surface area.
Now a wind increase of 1-2 knots will change the all of that

[beiland]

Originally Posted by Polux

My experience of sailing side by side with condo cats (without dagerboards) tell me that they cannot make a tacking angle of 45º and in fact you show bigger angles on the plotter. The angles are far from 90º, maybe 80º and that will make a tacking angle of 55º. A good monohull with that wind will make 10 to 15º better.

I have NEVER liked those short fat 'keels' they market on cruising vessels. I grew up when the first Morgan Out island were coming out, and those short fat keels on those boats were certainly lacking in windward ability. That's why I try to include a CB or dagger on anything I draw up,....CB preferably as then I can make it kick-up when I enter shallow waters that are always interesting to explore.

I suspect a great number of production boat builders would prefer those short fat 'keels' as its much easier and cheaper to produce, and less headaches down the road.

Stiletto offered a different kind of solution, a centrally placed daggerboard between the two hulls. But there support framework was just too bulky and unsophisticated. When I was developing my Dynarig design motorsailer, I came up with this.
Section 6 Galley, Dinette, Centerboard




There is a nacelle structure down the centerline of the vessel that acts as a bottom truss member, acts as a wave splitter, and provides a mounting for two asymmetric centerboards, thus eliminating any daggerboard or centerboard penetrations into the main hulls. And everything,…cables, bearings, boards are all above the load waterline…serviceable in remote areas.

Modern materials will make this possible with minimal bulkiness.

[smj]

Originally Posted by admiralslater

I will say from the out set that I am a cat guy. That video demonstrates one of the every interesting differences between multihulls and monohulls in that in light winds , and this is a generalization but in light winds equal boats will line up this way tris are are faster than cats and mono hulls are faster than both. I have raced dozens of all types and it has always been this way. I think the inertia of the mono hull works in its favour once the boat gets to speed. With cats and tris it is simpler as I believe it is a wetted surface area.

Now a wind increase of 1-2 knots will change the all of that

Like this Dragonfly 32 outpacing this 50' monohull racer.
http://youtu.be/hIAHyoHG8fs


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[2Hulls]

Originally Posted by Polux

My experience of sailing side by side with condo cats (without dagerboards) tell me that they cannot make a tacking angle of 45º and in fact you show bigger angles on the plotter. The angles are far from 90º, maybe 80º and that will make a tacking angle of 55º. A good monohull with that wind will make 10 to 15º better.

So? What is the obsession with tacking angles? Guess what angle the foiling AC cats tack through? 100 degrees (50 using your tacking angle description). Does that make them worse upwind than a "good monohull" 10 to 15* better? VMG is the relevant measure.

My experience sailing side by side with the better cruising monos of similar length tells me that they cannot make better VMG once the wind speed exceeds that necessary for them to get to hull speed.

Dave

[Polux]

Originally Posted by smj

Like this Dragonfly 32 outpacing this 50' monohull racer.
http://youtu.be/hIAHyoHG8fs

I don't see the relevance with the poor performance of condo cats upwind.

Besides the boats are not sailing close upwind. Nobody said that monohulls have not advantages in some points of sail, specially if we compare performance boats of the two types.

If you want to compare performance among cruising boats of different types (monohulls and multihulls) the best place is the rally or racing results.

There are two ARC going on with hundreds of boats on passage. That is a good place for having a look, even if in what regards the ARC multihulls have the advantage of being not sailed on his two more disadvantageous sailing conditions regarding monohulls: Sailing in light winds and sailing against the wind.

[smj]

Originally Posted by Polux

I don't see the relevance with the poor performance of condo cats upwind.

Besides the boats are not sailing close upwind. Nobody said that monohulls have not advantages in some points of sail, specially if we compare performance boats of the two types.

If you want to compare performance among cruising boats of different types (monohulls and multihulls) the best place is the rally or racing results.

There are two ARC going on with hundreds of boats on passage. That is a good place for having a look, even if in what regards the ARC multihulls have the advantage of being not sailed on his two more disadvantageous sailing conditions regarding monohulls: Sailing in light winds and sailing against the wind.

I posted this video to show the speed potential of the tri vs mono in heavier winds as Admiralslater stated in his post. You have to admit, the trimaran being 18' shorter and more of a cruising type version of the folding trimarans, absolutely smoked this racing mono.


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