Are "Performance Cruising Catamarans" safe?

[CaptainMarkS]

Wow. That's quite the debate going on here! As a fellow liveaboard Antares owner (in support of Mark Silverstein), I'm super happy I can't fly a hull in my home. I admit, there are times I wish we could beat upwind better, or sail faster in lighter winds. I'm super happy when I can tune our rig to cruise at 10-11 knots and get 250 miles under the keel in a day. I miss the adrenaline rush I got sailing thousands of miles in my Hobie 16. However, in higher winds and heavier seas, our "plodder" feels super safe and well balanced, and our short handed crew remains better rested (an element of safety) knowing we don't have to fiddle with sails as much because our vessel is more "forgiving" (as someone mentioned). At anchor (where we spend most of our time anyhow) we enjoy our comfort, the heavier displacement translating to less response to waves. I'm that minivan owner who sometimes wishes his car had the performance characteristics of a Ferrari, but wouldn't trade for one because this driver (me) would definitely push the car harder in search of excitement, placing himself and his crew in harm's way. I'm super happy for the Ferrari owner who enjoys his/her car. As with the debates on multihulls vs monohulls, or galley up or down, one can articulate pros and cons for each.

[boatman61]

Originally Posted by Lee Jerry

You guys familiar with some guy named Wharram?

Static stability calculates the wind speed that when reefing should start; dynamic stability accounts for gusts and is 60% of static value (i.e. the ‘real’ time to reef).

Fig 6:
Compares two catamarans: heavy and narrower (Cat A) vs lighter and wider (Cat B).
Cat A can carry full sail in winds 33% higher than Cat B.

Fig 8:
Cat B has to reef down to less sail area than Cat A to have the same stability as Cat A.

Fig 9:
Alternatively, Cat B has to nearly double her weight (to more than Cat A) to have the same stability as Cat A and carry full sail.

Ahh.. the benchmark for good catamarans, height of bridgedecks, beam to length ratio and more..

[lestersails]

Going back to the OP, gotta say I appreciated the video. Yup, he's pitching a product, but he was transparent about it (logo on the shirt and on the lower left corner of the video). I'll leave it to the naval design wizards here to argue about the fine points of designs and design metrics, but what I took away from the video was something I have seen many of you say in threads in CF - every boat is a compromise. I thought he was being more transparent about what compromises they made. Most marketing touts advantages and ignores disadvantages. Sure, it was more sympathetic to the benefits of cruising designs and the disadvantages of performance designs, but again, since he was transparent about his bias, I can take that with a grain of salt.

I agree that the skills of the sailor matter a lot and that a highly skilled sailor can be perfectly safe on the edgiest of cats. I think his beef is that the perf cat marketers pretend this is not so by avoiding the subject. Maybe a fair criticism. He was pretty clear that he would rather have a margin of safety on the boat for the unexpected squall than to get there sooner. I am sympathetic to that point of view because I know I am not skilled enough to sail a performance cat in anything but reliably fair conditions.

IMHO all marketing is lying - some lie more than others and I appreciated that video because I thought it was a little more honest than many.

[ozolli]

Originally Posted by lestersails

IMHO all marketing is lying - some lie more than others and I appreciated that video because I thought it was a little more honest than many.

It would have been honest with right numbers. And with right numbers the Antares would have been proportionally less safe compared with the performance cats in his chart

[Dizzyj]

Originally Posted by ozolli

It would have been honest with right numbers. And with right numbers the Antares would have been proportionally less safe compared with the performance cats in his chart

I’m interested in your pov here. I saw a lot of numbers in this thread that I just don’t understand. Can you net out for me the difference? The thing I noticed in his video was that the Antares seemed to have a lot of the same numbers as the more performance based cats but has a lot less sail area. But again I’m a newbie and admittedly know nothing .

[CaptainMarkS]

Originally Posted by lestersails

Going back to the OP, gotta say I appreciated the video. Yup, he's pitching a product, but he was transparent about it (logo on the shirt and on the lower left corner of the video). I'll leave it to the naval design wizards here to argue about the fine points of designs and design metrics, but what I took away from the video was something I have seen many of you say in threads in CF - every boat is a compromise. I thought he was being more transparent about what compromises they made. Most marketing touts advantages and ignores disadvantages. Sure, it was more sympathetic to the benefits of cruising designs and the disadvantages of performance designs, but again, since he was transparent about his bias, I can take that with a grain of salt.

I agree that the skills of the sailor matter a lot and that a highly skilled sailor can be perfectly safe on the edgiest of cats. I think his beef is that the perf cat marketers pretend this is not so by avoiding the subject. Maybe a fair criticism. He was pretty clear that he would rather have a margin of safety on the boat for the unexpected squall than to get there sooner. I am sympathetic to that point of view because I know I am not skilled enough to sail a performance cat in anything but reliably fair conditions.

IMHO all marketing is lying - some lie more than others and I appreciated that video because I thought it was a little more honest than many.

A nice and considered response, thanks!

[boatman61]

Originally Posted by lestersails

Going back to the OP, gotta say I appreciated the video. Yup, he's pitching a product, but he was transparent about it (logo on the shirt and on the lower left corner of the video). I'll leave it to the naval design wizards here to argue about the fine points of designs and design metrics, but what I took away from the video was something I have seen many of you say in threads in CF - every boat is a compromise. I thought he was being more transparent about what compromises they made. Most marketing touts advantages and ignores disadvantages. Sure, it was more sympathetic to the benefits of cruising designs and the disadvantages of performance designs, but again, since he was transparent about his bias, I can take that with a grain of salt.

I agree that the skills of the sailor matter a lot and that a highly skilled sailor can be perfectly safe on the edgiest of cats. I think his beef is that the perf cat marketers pretend this is not so by avoiding the subject. Maybe a fair criticism. He was pretty clear that he would rather have a margin of safety on the boat for the unexpected squall than to get there sooner. I am sympathetic to that point of view because I know I am not skilled enough to sail a performance cat in anything but reliably fair conditions.

IMHO all marketing is lying - some lie more than others and I appreciated that video because I thought it was a little more honest than many.

Nicely said..

[SoPacBound]

I appreciate everyone's input and that is what makes this forum great, different perspectives.

I'm leaning towards the lighter, faster side of things. I think I would get frustrated on a catamaran that struggles to sail in light winds and not able to achieve high average speeds in the right conditions.

The search continues....

[jtsailjt]

Originally Posted by SoPacBound

I appreciate everyone's input and that is what makes this forum great, different perspectives.

I'm leaning towards the lighter, faster side of things. I think I would get frustrated on a catamaran that struggles to sail in light winds and not able to achieve high average speeds in the right conditions.

The search continues....

I think that’s a wise choice if you want a cat. I’m a monohull sailor and the only cats I’ve sailed are charter cats in the Caribbean so recognize I’m very far from an expert on the subject of cat performance or safety. But most recently I chartered a 47’ cat in the BVI’s and after a week I couldn’t wait to get off the thing because of the way it performed and the way it felt as it flopped over the waves. Im sure that a decent monohull or a performance cat would have been far more enjoyable to spend time on. Even my very heavy center cockpit cruiser is much more fun and feels better moving through the water both under sail and power. These low performance charter cats make great condos with plenty of room for lots of people to share the cost of the charter, but they are so “unfun” that I don’t intend to ever sail one again. But I’d love to get a chance to sail a performance cat someday!

[fxykty]

Originally Posted by lestersails

…He was pretty clear that he would rather have a margin of safety on the boat for the unexpected squall than to get there sooner. ...

This part is what is wrong: as many of us with performance oriented cats have pointed out, we can sail at speed with a lot less sail area deployed than a heavier accomodation oriented cat. That means we retain our speed advantage and have more gust resistance than a cat that has to have full sail up in the same conditions.

With full sail up, the gust resistance depends on the specific boat and not broadly across categories. From Multihull Dynamics, the two stability figures for our cat (2003 Outremer 55L, though we have less sail area with our self tacking jib), a new generation Outremer 55 (18.5 ton vs our 11.5 ton), and an Antares 44.

SSpd (wind speed at which windward hull begins to lift): O55L 22.91, O55 24.86, A44 25.00

KSI (resistance to sideways capsize): O55L 38.59, O55 41.88, A44 42.11

I don’t see a vast spread in these numbers, i.e. what better margin of safety for the heavier, slower cat? And when we halve our sail area via reefing, whilst maintaining our boat speed, our stability indicators rise markedly. A heavier and fatter boat that requires more power to keep moving does not get that advantage.

So pick an accommodation oriented cat for its full size fridge, island queen beds, spacious salon area, etc. Pick it for its slower movement at anchor. But don’t pick it for its absolute safety, because the numbers show that isn’t a differentiating factor.

Hey, I totally admit that there have been a few conditions in which I wished I had a heavier boat that sits more in the water than on top of it. But my wife and I are both willing to accept those times (and slowing down to ‘normal’ sailboat speeds is one way to fix the movement issue) in return for having a boat that sails very well in almost all conditions.

And for those who say that cruising is 90% anchored or berthed, that may be so (our logbook since we moved on board permanently and left our home port shows 12% of days had sailing time), don’t you want to enjoy and be thrilled with your sailing time, rather than enduring it or just putting up with running the motor more often? Heck, if all you want to do is move from one anchorage to the next than a power boat is likely more efficient.

[smj]

Originally Posted by fxykty

This part is what is wrong: as many of us with performance oriented cats have pointed out, we can sail at speed with a lot less sail area deployed than a heavier accomodation oriented cat. That means we retain our speed advantage and have more gust resistance than a cat that has to have full sail up in the same conditions.

With full sail up, the gust resistance depends on the specific boat and not broadly across categories. From Multihull Dynamics, the two stability figures for our cat (2003 Outremer 55L, though we have less sail area with our self tacking jib), a new generation Outremer 55 (18.5 ton vs our 11.5 ton), and an Antares 44.

SSpd (wind speed at which windward hull begins to lift): O55L 22.91, O55 24.86, A44 25.00

KSI (resistance to sideways capsize): O55L 38.59, O55 41.88, A44 42.11

I don’t see a vast spread in these numbers, i.e. what better margin of safety for the heavier, slower cat? And when we halve our sail area via reefing, whilst maintaining our boat speed, our stability indicators rise markedly. A heavier and fatter boat that requires more power to keep moving does not get that advantage.

So pick an accommodation oriented cat for its full size fridge, island queen beds, spacious salon area, etc. Pick it for its slower movement at anchor. But don’t pick it for its absolute safety, because the numbers show that isn’t a differentiating factor.

Hey, I totally admit that there have been a few conditions in which I wished I had a heavier boat that sits more in the water than on top of it. But my wife and I are both willing to accept those times (and slowing down to ‘normal’ sailboat speeds is one way to fix the movement issue) in return for having a boat that sails very well in almost all conditions.

And for those who say that cruising is 90% anchored or berthed, that may be so (our logbook since we moved on board permanently and left our home port shows 12% of days had sailing time), don’t you want to enjoy and be thrilled with your sailing time, rather than enduring it or just putting up with running the motor more often? Heck, if all you want to do is move from one anchorage to the next than a power boat is likely more efficient.

What’s interesting is Multihull Dynamics has the original PDQ designed and built Antares 42 with a SSPD at 21.65 and a KSI at 36.46, making it less stable than all 3 cats in your comparison.
The maker of the YouTube video is also a CF member and poster but no comment from him on his video……..

[lestersails]

Originally Posted by fxykty

(stuff deleted)
SSpd (wind speed at which windward hull begins to lift): O55L 22.91, O55 24.86, A44 25.00

KSI (resistance to sideways capsize): O55L 38.59, O55 41.88, A44 42.11

I don’t see a vast spread in these numbers, i.e. what better margin of safety for the heavier, slower cat?
(stuff deleted)

Thanks for the interesting posts. I am confused. It looks like you are comparing two 55 foot Outremers to a 44 foot Antares. Does that make sense?
The Outremer 45 SSpd that he quoted was 15
And, FWIW he quoted the Antares at 26
(maybe these numbers he quoted are not valid?)

I would say that is a big difference. Eleven knots to me is a big difference. (26-15)/15 = 73% higher wind speed. This underestimates the force difference, which would be 26^2/15^2 = 300%

So I am having a hard time with your argument that there isn't much difference. But I am happy to concede the point if I am wrong about something here!

[smj]

Originally Posted by lestersails

Thanks for the interesting posts. I am confused. It looks like you are comparing two 55 foot Outremers to a 44 foot Antares. Does that make sense?

The Outremer 45 SSpd that he quoted was 15

And, FWIW he quoted the Antares at 26

(maybe these numbers he quoted are not valid?)



I would say that is a big difference. Eleven knots to me is a big difference. (26-15)/15 = 73% higher wind speed. This underestimates the force difference, which would be 26^2/15^2 = 300%



So I am having a hard time with your argument that there isn't much difference. But I am happy to concede the point if I am wrong about something here!

The Multihull Dynamics site has a Outremer 45, a 452 and a 4x. He quoted the 452 which claims to be 1/2 the displacement of the similar size 4x and 1/3 the displacement of the 3’ shorter 45. I think MD was fed some erroneous specs on the 452 displacement

[Chotu]

Originally Posted by jtsailjt

I think that’s a wise choice if you want a cat. I’m a monohull sailor and the only cats I’ve sailed are charter cats in the Caribbean so recognize I’m very far from an expert on the subject of cat performance or safety. But most recently I chartered a 47’ cat in the BVI’s and after a week I couldn’t wait to get off the thing because of the way it performed and the way it felt as it flopped over the waves. Im sure that a decent monohull or a performance cat would have been far more enjoyable to spend time on. Even my very heavy center cockpit cruiser is much more fun and feels better moving through the water both under sail and power. These low performance charter cats make great condos with plenty of room for lots of people to share the cost of the charter, but they are so “unfun” that I don’t intend to ever sail one again. But I’d love to get a chance to sail a performance cat someday!

Find me a nice, free spot in Penobscot Bay for a month or so and you can try mine! (not joking)

[Jweyndling]

I own a production catamaran because the comfort it provides ensures that my wife wants to go cruising. If it was just me, i would probably go for more performance. The biggest advantage I see is being able to sail in light winds when I currently motor. Also, if the wind picks up you can reef right down and still make really good speed. The theoretical high top speed is not what would really interest me. However I do believe it is really easy to get in a tricky situation. What the pros call “ angle of death” when you are reaching so fast that it dangerous to either bear away or round up when a squall hits.