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Multihull Popularity and Interesting Designs

70K views 579 replies 37 participants last post by  colemj 
#1 · (Edited)
For quite a while now there has been a huge interest in multihull cruising boats. At recent Annapolis Boat Shows there has been almost an equal area of water devoted to big multihulls as there has been to monohulls. There seems to be an equal number of multihull boat reviews in the major sailing magazines like Cruising World and Sail.

For some folks, multihulls seem to be the only way to go. For others they hold no appeal. For some on both sides of the mono and multi worldview, this topic is treated with near religious fervor. This thread was created to allow a civil discourse on a broad range of topics related to multihulls.

Hopefully this thread will provide a place for such topics as:
-Introduction and discussion of interesting new (or old) Multihull models
-Perceived 'whys and wherefores' of Multihull popularlity
-Multihull Technical issues
-Safety and seaworthiness
-Why you like or dislike multihulls
-experiences with Multihulls
-And other general Multihull related discussions.

While there are bound to be differences of opinions (and those are welcome within this thread and within SailNet in general), and bound to be some random amounts of thread drift, what will not be tolerated is personal attacks or dismissive comments.

Respectfully,
Jeff
 
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#79 ·
Sure, but on autopilot can mean a lot of different things. Were they in the salon watching reruns of gilligans island on autopilot, or did they have someone standing by the over ride. Surfing at 27 knots in a cruising cat, they would be pretty foolish not to have somebody keeping a close eye on things, whether they were lucky enough to survive or not.

https://ww2.bandg.com/product/triton2-autopilot-controller/
 
#87 ·
I took another look. There's a Triton controller at the helm but I don't see one at the nav table. And by the comments, it seems there were only the 3 people aboard.

So it looks kinda like Gilligan was "steering". In any case, I certainly wouldn't want to STEER in those conditions and speeds with a freakin' AP control.
 

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#80 · (Edited)
In one of these threads I remember our discussion about swept-back spreaders being a major problem for extended passages - not really "blue water" worthy.

Well, above I posted a couple of videos from the Distant Shores TV people who took a Bluewater 50 across the Atlantic...and pointed out how Discovery Yachts bought Bluewater Cats as well as Southerly Yachts (which this couple has long-sailed).

Now as I mentioned at that time, you can see some similarities in the boat types and usages here across this Discovery line (lifting keel monos for very shallow draft, etc.). And I think most would say that Southerly and Discovery yachts are definitely fit for crossing oceans. This Distant Shores couple certainly would - and have many, many times. But in watching some of their videos I came across something eye-catching...

Here is a still from one of their many Atlantic crossings on their Southerly 49 I believe...



Notice anything?

So, again, all these various dictums about what's good and bad for ocean crossings are FAR more blurred than has been traditionally painted on sailing forums. There are a hell of a lot of swept-back spreaders out there. I would just much prefer mine to be on a multi.
 
#99 ·
Notice anything?

So, again, all these various dictums about what's good and bad for ocean crossings are FAR more blurred than has been traditionally painted on sailing forums. There are a hell of a lot of swept-back spreaders out there. I would just much prefer mine to be on a multi.
This aspect is less extreme in a catamaran because of the beam. The spreaders sweep to an angle to the chainplates. The chainplates on a catamaran are much further out, so the sweep angle is less acute.

I agree that swept spreaders are no problem in any boat, but they are even less of a problem on a catamaran.

Mark
 
#102 ·
Hey guys - how does an Antares 44 cat pull down around twice the amount of an FP Helia 44 for the same length and year?
They are another step up in fit and finish and gear than the Helia, if not two steps, and they are bespoke made, so don't have volume economies. I doubt they build more than 2 a year. They also have a cult following, which helps support the price.

They are an old design, and pretty well superseded now. I've never seen one floating on its design waterline because the hull shape does not carry weight well. However, we are in a glass house in this regard...

Mark
 
#83 ·
In a tornado.

The same video shows a large sunken trawler as well. The most important lesson here was that this guy seemed to not know what he was doing and made LOTS of mistakes anchoring and even starting his engine. That's about it. He was lucky the funnel didn't get close enough to him to experience the same fate.

How are these examples relevant to this thread?
 
#84 ·
I don't see why it isn't relevant. The OP mentioned safety and seaworthiness in the first post. I thought we were trying to have a balanced discussion. If one person shows a vid of a cruising cat surfing at 27 knots to show seaworthiness, why isn't it reasonable to show the other side of the coin. Or, in this case, the other side of the boat :)
 
#86 ·
I would love to have a balanced discussion. I think the difference in my mind is that, as I said above, I don't expect ANY boat to be "safe" in a hurricane or a tornado strike. Those situations are far beyond the envelope for cruising.

On the other hand, I do think that getting hit by an F8 or F9 is relatively likely if you're out cruising - and knowing how to control the boat in those conditions is what I'm personally most interested in from the multi sailors around here.

Controlling the boat in a tornado doesn't have much value or relevance to me in this kind of learning. So I don't really go around looking for those videos, etc. Anyway, I just thought you guys had already created a thread specifically for multi capsizes. But this ain't my thread so knock yourself out.
 
#91 · (Edited)
I don't know, going 20+ knots down waves and having the choice of only 1° or 10° steering increments, plus the delay of moving back through those increments to swing the rudders? That's like steering a bicycle down a steep winding street holding string attached to the handlebars.

No thanks. I'd MUCH rather hand-steer and have a feel for what the boat is doing.

PS - Just saw your remote. It looks like it's not incrementally constrained like the helm controller (though I don't see any details on how those p/s buttons work). Still - no thanks. Not in those conditions. But it doesn't really matter because I'd likely have a drogue out and be going WAY slower than they were. So it wouldn't be nearly as much an issue.
 
#92 ·
Don't knock it until you have tried it. They are not bad. I ran a 60 foot stern trawler with one (not a B&G) and I never ever used the wheel. It was good for the owners because they could drop a crewman. Basically I could run the crane and drive the boat at the same time. Which left one man to run the net hauler and one to haul the net (2 crew plus myself). The unit I had also had gear controls but no throttle. So you would set the throttles on the bridge, walk back to the crane, left hand on the remote control, right on the crane Joy. We hauled nets in some pretty rough conditions, granted, not at any kind of speed, but net hauling is not easy because you need to back into the seas so you don't blow over your trawl.

Keep in mind, in your vid, the cruisers aren't in control, they have a pro skipper with them (I think).
 
#93 · (Edited)
Yeah, as I said, I have no problem using the AP and/or a remote at much lower speeds. I've done a few thousand miles of that. And though I never quite got around to connecting it, I could have used our iPads/iPhones as AP controllers/repeaters with our iNavX/iMux setup. I would have loved that.

So, I'm all about the AP. Just not at speed in big waves...while relying on Bluetooth. Nope.

PS - I'm saying these things from the perspective of my experience on monos (and a beachcat). Maybe the cruising cat folks will tell me it's different with more responsive multis. I don't know. We'll see.
 
#94 ·
Thrill rides down big wave face can reach a point where it's not so good. 35 ft breaking following sea like what's common off the West coast can broach or bury most vessels regardless of expert steering.Comes a point where you turn about if you can and dodge under power until things improve. If you are North Atlantic you hope you don't ice up and roll. Lots can go wrong ,drogues chafe, loss of power .Capsizing your cat because you think it's invincible and you tube is all just tells me you need some real experience before I get impressed.
 
#101 ·
We don't do 27kts, and would never do it. Our AP (the one above) steers us out of potential broaches all the time by never getting us into broaching positions. It anticipates these as well as I can, does so longer than I can, and does it at night - where I cannot.

Our AP has also steered us just fine for 24hrs downwind in 35-40kts (reefed to keep the boat at 8kts) with a broken steering linkage, where the only boat control was the rudder with the drive connected. I didn't even know the link had broken - all I remember is thinking that the AP was a bit more active than usual.

These AP's are continually monitoring all instruments and boat performance 100 times per second, and are continually adjusting their steering to suit. They actively avoid jibing downwind, and through rate sensors on 9 axis, they know before hand when a broach is possible and steer away from it. Heck, it even continually optimizes VMG upwind, and can also steer to a polar table. At some point in the above link failure, I'm sure the boat got really squirrely, but the AP almost instantly picked up on that and adjusted the steering parameters to compensate.

BTW, it isn't possible to get out of a steering linkage failure by hand steering - there is no connection of the wheel to the rudders then. The AP is the only hope.

Again, if you haven't used one of these newer AP's, you will be surprised at how much has changed.

Also, see my edit above - I now understand why you linked to the Triton.

Mark
 
#106 ·
So I have an honest question for you multi-guys, which I'll setup with a Disclaimer and my specific limited cat experiences:

DISCLAIMER:
Anyone who wants to sail anything, i'm on your side. To me, the argument over who's form of fun is better than they other guys fun for an absolutely unnecessary frivolous activity like sailing is, well, a debate for people who apparently aren't getting enough conflict in their lives. The real question is will anybody be left sailing anything 50 years from now, or will they all be sitting in their living rooms wearing VR googles and getting pizza delivery by drone, while arguing about what VR experience is better than another on social media :).

So, with that disclaimer, I'll undo my own argument by stepping into the fray:

MY CAT EXPERIENCE:
Is my perception wrong about cruising cats? I've only chartered them twice, once in Belize and once in the BVI. I found that even when I was going 8 knots, I felt like I was sailing my dock. I had to look at the water rushing by or I'd think I was still tied up. It just didn't do it for me. That said, anchored up with my friends, it was a wicked good party platform and comfortable living. Not to mention, didn't even need to put my beer in a holder underway.

At the other end of the spectrum, I really enjoyed when I was younger getting out on the trapeze on a Hobie 16. What a blast. Yea, I read smack and others experienced pitch poles, and yea I did too. As a teen ager swinging up in the air when a hull went in was exciting. Gotta get your weight aft when a hull flies and it really goes.

THE QUESTION:
So the question is, are their cruising cats that aren't like sailing your dock? More like the Hobie, a bit more civilized, without turning into a barge with a mast on it? That might interest me. Anyplace I can charter one?
 
#115 ·
So the question is, are their cruising cats that aren't like sailing your dock? More like the Hobie, a bit more civilized, without turning into a barge with a mast on it? That might interest me. Anyplace I can charter one?
In absolute terms, no. On the other hand, there aren't any 40-60' cruising monohulls that sail like a Laser, only a bit more civilized.

In relative terms, there is a whole spectrum of sailing "feeling" in cruising catamarans, just like there is in monohulls. But for both types of boats, if pure sailing joy is what you are after, you will be disappointed unless you take a nice little performance sailing dinghy along with you.

Most people associate healing and riding in sync with waves while the boat moves in a certain way as their understanding of sailing "feeling". This is more a Pavlovian response, because this is how almost everyone starts in boats, and continues for a ways before moving to a catamaran. And then the move is usually to a large catamaran - where they think they are driving a dock.

Moving from a Laser, to a J35, to a Formosa 50 will give one the same experience.

However, catamarans do have their "grooves", and a lot of the joy is to be speeding along at 9-10kts with a "dock" under you, while you play guitar, cook a good meal, take a nice nap in the hammock, or pay attention to your spread of 4-6 fishing lines.

This is also a learned response over time, and going back on a mono heeled and rolling feels more like surviving than sailing.

And what one wants for an afternoon sail is completely different than what one wants for a 2-3 week passage (or even a 1-2 day passage). Sporting sailing is fun for one and can be tedious for the other.

So it depends on what you think sailing needs to "feel" like, and to what degree you will allow that to degrade before not enjoying it. Also, how you will be sailing. Again, a 50' Oyster is not going to "feel" like a Melges 24 - so there is always going to be a degradation tradeoff.

BTW, it is a very reasonable question and didn't need a disclaimer.

Mark
 
#108 ·
You are correct, commercial power cats only in this size range, but one was a high speed rig (3 years, faster than 27 knots) and of similar size to the one in the vid, 60 feet. Same rules apply surfing down waves whether recreational or not, except that power cats are easier to control because you can back off the power.

You are probably also correct that a helmsman could not have steered out of a serious broach at those speeds, but I definitely would have one standing by with the AP over ride in hand.

To be clear, I am not saying turn the AP off and steer by hand for the duration of the blow. I am saying it would be wise to have a real helmsman standing by with the ability to immediately over ride the AP if necessary, that is why I linked the pics of the portable controls. If you have the control with you and you see something going sideways, like say a telephone pole floating in the water, you just hit the jog button and over ride, then let AP take back over.
 
#111 ·
What upsets me about this thread and many threads on this forum is how some neglect a basic reality that underpins most cruisers mentality when thinking about boats. This reality extends across all classes be it monos,multis or motor.

There are good seaboats and those not so much.

Comparisons between classes of boats is foolish if not also accounting for if that specific craft is a good or bad seaboat. Grand Banks are wonderful, beautiful, comfortable great loop or coastal cruisers. Sea rays give great bang for the buck. Neither are designed to be or are expedition yachts.
You can blow big bucks and get an light ice Diesel Duck 492 for less than the glorious GB but only the first is the rtw boat. You can quadruple the purchase price and walk on a Seaton or Cape Scott and get the bling with the sea keeping ability to sail the Southern ocean.
The same occurs with monos or multis.

Looking at the title of this thread believe we should be looking at specific boats and critiqueing that specific design. Multis have several vulnerabilities as do monos or motor. This obsession about inverting limits this thread to one of many concerns so is much less informative than it could be.
Look at the various cats you see in Caribbean charter. These are like the Searays. Even in that relatively benign setting one sees:
They hobby horse. When motoring to windward( such as entering an anchorage) this is so extreme as to be dangerous to the occupants. Their beam to length ratio is moderate but capsize risk decreased by moderate rigs. They aim toward one level living with large expanses of glass. But a violent pooping may result in failure of the aft glass enclosure or its rim of support leading to down flooding. The steering is designed for the stresses of forward movement. Falling backwards after being stalled on the face of a wave may result in catastrophic steering failure. Interior living space is optimized for pleasant living at anchor with bridge deck forward of the mast and beam of hulls brought forward to allow a four berth set up. Beyond unpleasant burping the behavior in a seaway is compromised. They have low aspect fixed keels. Beyond decreasing ability to point increased possibilities of “tripping” on a large wave face is increased. Helm position is high and exposed. This is tiring to the helmsman and compromises ability to see the whole boat.

Now compare this to a boat designed as a seaboat. Perhaps the Rapido 60referred to above.
Single rudder. No linkage issues. Very fine hulls and very wide beam with much more force required to turn turtle. No significant structure beyond central hull before the mast. Daggerboard no fixed keel. Protected helm station. Walkways and rig designed to be worked in a seaway. No large glass expanses vulnerable in a pooping or from green water.

In short just like a Diesel Duck would seem to be a better seaboat than a Searay the R60 would seem to be a better seaboat than the charter cat.
 
#131 ·
What upsets me about this thread and many threads on this forum is how some neglect a basic reality that underpins most cruisers mentality when thinking about boats. This reality extends across all classes be it monos,multis or motor.

There are good seaboats and those not so much.

Comparisons between classes of boats is foolish if not also accounting for if that specific craft is a good or bad seaboat. Grand Banks are wonderful, beautiful, comfortable great loop or coastal cruisers. Sea rays give great bang for the buck. Neither are designed to be or are expedition yachts.
You can blow big bucks and get an light ice Diesel Duck 492 for less than the glorious GB but only the first is the rtw boat. You can quadruple the purchase price and walk on a Seaton or Cape Scott and get the bling with the sea keeping ability to sail the Southern ocean.
The same occurs with monos or multis.

Looking at the title of this thread believe we should be looking at specific boats and critiqueing that specific design. Multis have several vulnerabilities as do monos or motor. This obsession about inverting limits this thread to one of many concerns so is much less informative than it could be.
Look at the various cats you see in Caribbean charter. These are like the Searays. Even in that relatively benign setting one sees:
They hobby horse. When motoring to windward( such as entering an anchorage) this is so extreme as to be dangerous to the occupants. Their beam to length ratio is moderate but capsize risk decreased by moderate rigs. They aim toward one level living with large expanses of glass. But a violent pooping may result in failure of the aft glass enclosure or its rim of support leading to down flooding. The steering is designed for the stresses of forward movement. Falling backwards after being stalled on the face of a wave may result in catastrophic steering failure. Interior living space is optimized for pleasant living at anchor with bridge deck forward of the mast and beam of hulls brought forward to allow a four berth set up. Beyond unpleasant burping the behavior in a seaway is compromised. They have low aspect fixed keels. Beyond decreasing ability to point increased possibilities of "tripping" on a large wave face is increased. Helm position is high and exposed. This is tiring to the helmsman and compromises ability to see the whole boat.

Now compare this to a boat designed as a seaboat. Perhaps the Rapido 60referred to above.
Single rudder. No linkage issues. Very fine hulls and very wide beam with much more force required to turn turtle. No significant structure beyond central hull before the mast. Daggerboard no fixed keel. Protected helm station. Walkways and rig designed to be worked in a seaway. No large glass expanses vulnerable in a pooping or from green water.

In short just like a Diesel Duck would seem to be a better seaboat than a Searay the R60 would seem to be a better seaboat than the charter cat.
I see you have read Chris White's Cruising in Multihulls book. It is a good start, but is pretty dated now, and only represents a single viewpoint among many different ones from very qualified designers and builders.

I have avoided responding to some of your posts in other threads because your information is just too twisted up and poorly presented to try and untangle and add context.

But I would like to point out here that your assumptions about, and categorizing/grouping of, production catamarans and their designs is just wrong on many, many levels. I could spend a page or two just unwinding this post. Like how a good sea boat should have a single rudder, and that single rudders do not have any linkages to fail and that a very wide beam is good. Good grief - that is a general lack of understanding of catamarans, steering systems, and dynamic stability.

Production cruising catamaran designers and engineers include Morelli and Melvin, Marc Van Peteghem and Vincent Lauriot-Prévost, Eric LeRouge, Jeff Schionning, Angelo Lavranos, Phil Southwell, Alex Simonis, Kurt Hughes, and many other extremely qualified people. Many of their designs and philosophy are in contrast to Chris White's, and they have a more extensive portfolio and experience.

I suggest you take your good start at understanding catamarans and their designs (his book is where I started), and allow yourself to push further into the topic with a more open mind. A lot has developed since 1990, when Chris White wrote his book.

BTW, do you realize that more Chris White catamarans have capsized than any other builder/model? That isn't even taking into account that there are 100 times fewer Chris White boats than other builders. While the total number of catamaran capsizes while not racing is extremely small, Chris White designs do hold that record.

FWIW, I like Chris White designs.

Mark
 
#129 ·
Mark - can you explain the more subtle differences in docking between a two-engine cat and a mono? I have to admit I was never the perfect docker on our mono. We always backed into slips, and ~5% of the time I would be carrying too much speed, or not aligned correctly, or whatever.

It seems you have much more fine control over a cat - both in terms of the engines, but also in terms of dealing with the momentum. Being able to literally spin the boat on a dime, and not have to mess with back-and-fill like on a mono, sounds pretty dreamy.
 
#141 · (Edited)
There is no subtle difference between the two - the difference is night and day, black and white. With two engines 20' apart, you can make the boat do a tango through a corkscrew. Strong cross winds are the only thinking one really needs to do because of the extra windage. Our catamaran made me an overnight docking expert.

Our previous monohull was a full-keel, barn door rudder, and undersized prop in an small aperature behind a thick deadwood (a real "blue water boat"). The best I could do with that boat was hang fenders everywhere and keep our liability insurance paid.

All control is done with engines while the wheel is locked in center. It is possible to use the rudders with engines to make the boat go sideways - once you get the hang of it, you can simply exit/enter a dock sideways like you have bow and stern thrusters.

Mark
 
#130 ·
How are you 2 saying I am stuck on APs. Somebody posted a vid of a big cruising cat surfing at 27 knots and I made one post basically saying I thought it would be foolish to leave that boat doing those speeds with an auto pilot in complete control of the boat. Then you two responded with pages of posts trying to prove me wrong, and it isnt working. I still think its foolish.

I disagree that a big cat wont broach. There are physics at play here and those physics dont necessarily point to a 60 000 lb boat doing a stern over bow somersault down a wave front. When the bow stuffs it stops, the inertia in the 60000 lb boat wants to keep going, gavity wants the stern to stay down so that inertia could result in a horizontal rotation instead of a vertical rotation, thus resulting in a broach.

I know this isnt painting a very pretty picture of some of the challenges that can be faced by some boats in heavy weather, but its how it is. In conditions like that it really is a good idea to slow the boat down. Failing slowing the boat down, at least try to keep her under control, you do that in part by steering, not all, but some broaches can be recovered from, but not generally by an autopilot.
 
#134 · (Edited)
I continue to be amazed at the level of comfort on a cat while underway. Here is a Lagoon 400 sailing across the Indian Ocean from Cocos Keeling to Chagos...



Now, though I think Delos had better overall weather on this same passage judging by the videos - compare the level of fatigue/sickness of the crew to the above family, and keep in mind that there are 7 young and fit crew on Delos for watches, etc. - and just the mom and dad and kids on the Lagoon...



Good comparison I think. I would take the Lagoon over the Amel any day. Though I have to say, these videos make it obvious that multhull sailors can't make a good video to save their lives. I'll have to fix that.
 
#138 · (Edited)
Okay Mast.

I'm in this thread to talk about cruising cats. That's all. A couple of the capsize examples above are from hurricanes which is why I mentioned it. To be clear, I don't hold that multis are great boats for hurricanes or tornadoes regardless of where the boat is in proximity to land.

Apart from that, I'm not interested in arguing. I'm trying to get info from multi sailors about multis.
 
#155 · (Edited)
Okay Mast.

I'm in this thread to talk about cruising cats. That's all. A couple of the capsize examples above are from hurricanes which is why I mentioned it. To be clear, I don't hold that multis are great boats for hurricanes or tornadoes regardless of where the boat is in proximity to land.
Most capsizes occurred NOT in hurricanes so that was just some tactics to divert attention from a real problem.

Clearly, there are quite a few cases where catamarans capsize in various high-wind conditions that have absolutely nothing to do with hurricanes. Even at anchor. This is a life-threatening situation and it is something I would take into consideration in any decision. I am not saying this danger is enough for me to never ever wanting to own or sail a cat but it it is one of several important factors.

Mind you, I have never sailed a cruising cat (that makes two of us...) and I don't have much interest in doing that. I have had some very good sailors report that sailing a cruising catamaran feels like 'sailing a Zamboni.' :devil I might appreciate it when I feel I am getting old...
 
#144 ·
Two engines - one with right hand prop and the other with left hand. Zero prop walk, and they can be put on specific engines so that their prop walk counteracts the torque of the engine being offset when running under one engine. Most saildrives have the same gearing and ratios in fwd/rev, so this is easy to do. I don't know about shaft transmissions.

Don't see how your Hobie can have so much prop walk...

Mark
 
#143 ·
Twin screw boats still have prop walk, the difference is, you get to chose the engine and there for which way to walk your stern. You can split, which allows the boat to turn in place without advancing, you can do a reverse split that allows you to walk the boat straight sideways in either direction. You dont normally put both engines in gear in the same direction for close quarters maneuvering unless its windy, but you can. You can flare the bow like a boss with a cat and you can stop in a straight line by using both engines.

Twin screw cats really are amazing to park. The only thing better is a twin jet cat.

Any decent seamanship book will have a chapter on twin screw boat handling, Chapmans Im sure does.
 
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