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post #121 of 577 Old 02-24-2018
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Re: Multihull Popularity and Interesting Designs

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Originally Posted by SanderO View Post
There is a diminishing return. My AP has steered 10s of thousands of miles... coastal, off shore. It's not perfect but it does better than I do and doesn't need rest or food. The course plots are damn good... But sure there is some wandering.

The AP does not have the full range of helm rotation.... it basically MOSTLY makes rather small course corrections based on whatever data it is using. If I wanted to turn hard over instantly.... AP can't do it. I can manually.

So for example when I approach the fuel dock in NPT... I approach heading south in the channel and make a tight as possible 180 even using reverse to kick the stern over. Not possible with the AP. Tight AP 180 won't work because there is not enough sea room... I use AP until I am ready to execute the turn. I doubt a new gen AP would do this.

I see little reason to "upspec".... but I would need to experience it to make the determination.
I'm not sure many would want to use their AP to go to a fuel dock. We use ours for almost everything, but will dock the boat by hand. Also not sure how many would require their AP to go hard over instantly.

On the other hand, our AP has full range stop-to-stop control of the helm, and a 5 second hard over time. With a push of a single button it goes into manual mode, where holding down the buttons moves it about as fast as I can. If we had the other controller, it has a knob for steering like this.

I believe I could dock it using just the AP, but it is much easier to use the wheel based on the motion efficiency alone. Underway, if we need to dodge something, the AP can turn the boat 90* in 2-3 seconds. Our AP can auto tack and has adjustable tack times. Ours is set for 6 seconds, and it does go through tacks that fast. It could go faster, but catamarans don't tack that fast.

Mark

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post #122 of 577 Old 02-24-2018
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Re: Multihull Popularity and Interesting Designs

This is a great post cape...my thoughts below...

Quote:
Originally Posted by capecodda View Post
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 .
Yes, there will be sailing. From everything I see, there are more young people getting into sailing now than there has been for decades. I think that's because the used boat market it absolutely flush with "cheap" boats. But they are also getting into much higher end boats because a large chunk of of them have far more spending power then ever in history for this group (have you seen what a software developer pulls down in salaray?).

So, no worries.

Quote:
Originally Posted by capecodda View Post
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?
All I can add here is from the beachcat to mono perspective. What you describe is very similar to what actually happens as you go up in size for monos. Going from a C27 with a tiller, to a Pacific Seacraft 37 with a wheel felt like "losing touch" with the performance through the water. Yet, when you think about maintaining that level of "touch" over hundreds of miles 24/7 for days on end? No thanks. I'll leave that to the beachcat.

It was the same going to our Hunter 40. It felt slower and far less responsive at first until I got ITS feel. It wasn't slower or less responsive - actually the opposite.

So, though I can't tell you about this phenomenon on cruising cats, I have a hunch it's very much the same.
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Re: Multihull Popularity and Interesting Designs

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Originally Posted by colemj View Post

Edit: I see now that this AP controller shows in the video. While I wouldn't be doing those speeds in that boat, I would have no problem letting this AP have complete control. It is better than I am. Remotes are useless for instantaneous steering, like one is proposing necessary in the video conditions. They are fine for course changes, dodging, and the like - but not as a substitute for hand steering in large conditions. Leave that to the AP.
Just noticed this. Not sure when the last time you took a big broach in big weather on a big boat was, its not a guaranteed game ender, but stuff can get real fast. Stuff can break, rig can break, breakers might trip, people might fall. The boat might actually exceed a 90 degree course correction. If you have no one near the over ride, the auto pilot will do what auto pilots do, turn you back on course, back down wind, you will pick up speed again, maybe broach again, maybe stuff again, then you have more stuff breaking, more people falling.

Helmsman sitting at a control station or with a portable over ride on his person may decide the best escape from the broach is to temporarily turn up wind, slow the boat down, even if its just for 30 seconds so people can get back on their feet, he may decide to turn beam to the sea, or sail diagonally down the wave to scrub some speed. Your auto pilot that you insist on setting and forgetting can not do this.

You may convince the readers that surfing big boats in big seas that setting and forgetting the auto pilot is a good move, but you will not convince me it is, no need to even try.
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Re: Multihull Popularity and Interesting Designs

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Originally Posted by smackdaddy View Post
I think the disconnect in this ongoing conversation really has very little to do with the autopilot - whatever brand and technology we're talking about. The problem is that this boat was out of control. The human intervention, first and foremost, should have been in getting the boat slowed down. Until that happened, it doesn't matter what kind of AP they had or how awesome it was.

That, I believe, is what Mark is saying - as am I.

Vendee boats do 27+ knots pretty easily for tens of thousands of miles on their APs. They are not Leopard 50 cruising cats. So it's not about the AP.
I guess you missed it, I have stated these folks are sailing on the edge. The auto pilot might not be relevant to you, but if you are going to exceed safe sailing speed, keep your finger on the AP over ride. Not sure how this message got missed.
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post #125 of 577 Old 02-24-2018
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Re: Multihull Popularity and Interesting Designs

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Originally Posted by smackdaddy View Post
That's good feedback. Yes, my experience has been on older units. I know that the Vendee boats rely almost exclusively on AP (Lecomble & Schmitt I believe) - so I have no doubt that the technology has come a long, long way.

I guess what bugs me so much about that video is that they are sitting inside watching as the boat - at least to my eye - gets increasingly out of control. And they are talking about "breaking records". To me, and please let me know if this is wrong, they are completely disconnected from reality. It just looks like they are, as you say, "leaving it to the AP" - but their problem isn't steering - it's boat control. Therefore, it seems they are asking FAR too much of that AP and should be DOING something to maintain safety.
Lecomble and Schmitt only make hydraulic drive units. I believe the autopilots on all of those boats are either B&G or NKE. These two brands are pretty much all professional racing boats use, and the technology is carried down into their consumer products (the important and proprietary parts are mostly just algorithms and software after all).

I agree, and have tried to state in different ways that there is no way we would find ourselves in that state. I don't know why the discussion got focused on autopilots and how to use them properly when doing 27kts in bad seas in a production catamaran - autopilots are completely beside the point here, and are rather like debating the car stereo while doing 100mph on an icy road with bald tires.

The boat shouldn't be allowed in that state period. If it was properly set to a reasonable speed, their would be no danger regardless of the quality of the autopilot.

Mark
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Last edited by colemj; 02-24-2018 at 01:26 PM.
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post #126 of 577 Old 02-24-2018
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Re: Multihull Popularity and Interesting Designs

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Just noticed this. Not sure when the last time you took a big broach in big weather on a big boat was, its not a guaranteed game ender, but stuff can get real fast. Stuff can break, rig can break, breakers might trip, people might fall. The boat might actually exceed a 90 degree course correction. If you have no one near the over ride, the auto pilot will do what auto pilots do, turn you back on course, back down wind, you will pick up speed again, maybe broach again, maybe stuff again, then you have more stuff breaking, more people falling.

Helmsman sitting at a control station or with a portable over ride on his person may decide the best escape from the broach is to temporarily turn up wind, slow the boat down, even if its just for 30 seconds so people can get back on their feet, he may decide to turn beam to the sea, or sail diagonally down the wave to scrub some speed. Your auto pilot that you insist on setting and forgetting can not do this.

You may convince the readers that surfing big boats in big seas that setting and forgetting the auto pilot is a good move, but you will not convince me it is, no need to even try.
I don't know why you keep saying that I insist on setting and forgetting the AP while doing 27kts in those conditions. I have stated repeatedly that our boat will never find itself in that state. You seem to be creating the argument.

Once the boat has turned far off course, or steering control is lost, our AP sounds a loud alarm and tries to hold course - it does not try to go back to the original course. Our AP also tries to not steer down waves in a reactive mode such that the boat is yawing. It steers like a helmsman by feeling the point before the bow yaws and applying early rudder to compensate. In the trough, it does the same to bring it back before it yaws.

I don't know of many people who can recover a boat from a broach. Generally the physics overwhelms the steering foils and the best anyone can do is let the boat get on its feet and proceed from there. On a mono, the rudder and most of the keel isn't even in the water. This is not the case for a catamaran.

I don't understand why you are wound up on this AP thing? The video does not represent catamarans in general or any catamaran owner I know. The use of the AP is inconsequential to the situation they are in. My feeling is that a helmsman could not do a single thing differently than their AP to avoid, or get them out of, trouble. The video, IMO, only represents someone operating their boat unsafely - and the AP has nothing to do with that. Why aren't you picking on the full sail set instead?

BTW, broaching is rare on a catamaran because they tend to slide in those conditions. It is more a monohull thing. Pitchpoling from burying a bow is more likely in a catamaran.

Mark

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Re: Multihull Popularity and Interesting Designs

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Originally Posted by MastUndSchotbruch View Post
How do you avoid tornadoes when you are cruising? Even in relatively tame (weather-wise) Maryland we have tornadoes all the time. I would imagine they are more common in Florida and the Gulf. Case in point: summer before last when I was coming up the Bay (cruising!), the weather started to look pretty threatening and I was pondering if I should hunker down for a bit in the Severn River. Well, the decision was made for me when the CG came up on 16 with a tornado warning (not watch) for -- tadaa-- the Severn River!

I stayed in the middle of the Bay and things went well, never saw the tornado though A LOT of wind, thunder and lightning. I certainly don't want to get hit by a tornado at any time and I would expect very severe damage to my boat including dismasting. But I do not expect that it flips upside down (and stays there) or sinks. And you consider this normal for a catamaran, and that at anchor, with no sails up?

So, my point is, a boat for which encountering a tornado is "far beyond the envelope" is by definition not a boat for cruising.
Well, keep in mind that I live in Texas and we had our boat in Florida. So tornadoes and major-storms/hurricanes are relatively common in our lives. Avoiding hurricanes is not that hard as I've discussed in my videos. You get off or stay off the boat after making it as secure as you can. In that case, boats of all kinds are still destroyed - but you are safe.

But again, that's not "cruising". That's simply a place where boats are sitting (either on the hard or in the water) getting hit and destroyed. So the type or make of boat doesn't matter. That's what we're seeing in the above examples here and why I'm not sure they really mean much to this discussion. Cruising, at least the kind where you travel longer distances from place to place, typically happens away from these anchorages in the examples.

Now, avoiding tornadoes can be very easy as well, or impossible. Every Texas and Florida sailor knows the maxim "Never cruise in Kansas". And we all pretty much stick to that. If you run the numbers, you'll see that there have been very few cruising sailors killed in Kansas by either tornadoes or hurricanes in either monohulls or multihulls. Heh-heh.

On the other hand, it can be impossible to avoid in JUST the right circumstance - like getting hit by lightning...especially if you're relatively close to land where thunderstorms can be far more powerful (like your example which I would equate to sailing in Galveston Bay like we used to do - but I wouldn't call that cruising).

We got fairly up-close to one (actually a big waterspout) while cruising off the coast of Florida...



Now, just like lightning, had this thing been coming right at us I don't think we could have avoided it. And had we gotten a direct hit - who knows what could have happened. And, to the point I think you and others are trying to make, it would have potentially been more dangerous in a cat simply because air can get under the central platform and make the boat fly (though that's impossible to say for sure). This is what I assume happened to that other boat shown in the Florida video that was hit by the tornado - and maybe even that Prout that Noelex mentioned.

But, I personally don't buy boats for their tornado or hurricane performance. I have no interest in that. I buy them to cruise. Our Hunter did very well on the hard in a direct strike from Category 2 Irma - and we were safe at home. But there were also a few cats in the same yard that did just as well. So, again, I'm not sure what that has to do with cruising.

As for the tornado, we got lucky. I think Charlie Doane frames your concerns about this best in that article on the CWD capsize I linked above...

Quote:
Discussing the event with Charles Nethersole, it really did sound to me like the purest piece of bad luck a bluewater sailor could ever hope to encounter, as though God himself, with no warning, had suddenly decided to poke you with a finger and squash you like a bug.
Indeed. Thar be dragons - and they don't care what kind of boat you're on.
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Re: Multihull Popularity and Interesting Designs

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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
Hehe. We have a friend cruising in a catamaran and he is anchored next to us right now. He just sold his virtual reality company, but is still working with the new owners in transition. He has top of the line computers and gear on his boat for doing his work. Those computers use 50-80 amps when rendering and displaying, and he has sensors installed about his boat that track movements.

When we go over there, we put on the headsets, the haptic feedback gear, and .... watch sailing!

Sometimes. He has a lot of footage of his boat under sail. Other times we are flying with the Blue Angels, or exploring Google Earth, or (my favorite) running around with the Miami Dolphin cheerleaders as they bounce about and go to the beach.

So maybe the future will be people sitting in their boats wearing VR googles!

Mark
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Re: Multihull Popularity and Interesting Designs

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.
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Re: Multihull Popularity and Interesting Designs

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.
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