Anti-Capsize Technology and Systems

[Tupaia]

There is not one single solution that is appropriate in all conditions.

Being hit by a gust from an acceleration zone between or close to land promontories usually includes a change of wind direction. Bearing away or heading up is not always prudent. This situation should not come as a surprise and should be prepared for either by being able to dump the jib, or being under canvassed to begin with.

Open ocean gusts tend not to involve a massive direction changes where bearing away or heading up is more easily decided. However, while jib sheet releases might be useful in some circumstances an automatic mainsheet release might result in being powered up at a critical moment when it would have be far better to dump the traveller instead.

I see all of this as being made worse and a big disadvantage on cats with remote or flybridge helms unless the various control stations are occupied at all times.

Whichever line is involved, being able to dump it quickly is also a major failing of self tailing drum winches that can take several seconds to release and often result in snags. Rope clutches work well on small bots but can be impossible to release under heavy loads on bigger boats. This was the reason why my control winches are captive Setamars that can be dumped instantly from anywhere in the cockpit.

Unfortunately Setamar winches are no longer in production.

[Franziska]

Originally Posted by catsketcher

I think that Sean and Rob are probably onto the easiest way to implement a system - bear the boat away or round it up in an emergency manner under autopilot.



To make things easier you could probably implement into something like a PyPilot a little bit of code that says Mode 1 - "When the wind gets to ____ knots bear away _____ degrees in fastest manner possible" or Mode 2 "When the wind gets to ______ head up ____ degrees in fastest manner possible".



This would obviate the need for sheet releasing systems which are prone to error and challenges in getting them to release. It is also the way I sail my boat if I am challenged by a squall - get the boat heading the correct way first and then sort out the rest. Even a few seconds bearing away or heading up woudl be gold in a nasty squall.



My son is getting closer to installing Pypilot on my catamaran. I could then integrate the wind sensor into the system and see if some code could be written to do the course changes. In fact the boat could be set to sail at a safe angle by apparent angle until told not to.



cheers



Phil

Additionally automatic mainsheet release in a cockpit mounted system might be dangerous as people might well be close to the snake pit.

So might be that the autopilot system combined with a jib release would be safest.

[Manateeman]

Just for forum readers who might not be familiar with the subject, here is another anti capsize system...it might be a bit outdated but we are not sure.
ACS system. The inventor is Captain Roger Ganovelli
Could a forum member help the blubber butts post the best links please?
We found it on Bateau.com / Boatsnews.com
We understand Captain Ganovelli is a well known catamaran skipper.
What we were surprised to find was that the device was routinely used in multihull races and mandatory in some race class.
It would be nice if a forum member could put together a list of these systems and references. A list of catamaran capsizes would be very interesting reading.
There have been discussions on anti capsize systems on this forum and others before but we haven’t seen a complete list. Would make a great book.
Again, thanks to all who have made serious contributions to this important subject from which even monohull owners might benefit.
Captain Mark and the manatee crew.

[smj]

https://www.boatsnews.com/story/2946...for-multihulls

[Tupaia]

There looks to be only 2 contenders.


The costings seem to be somewhat closely guarded secret, although I never understood this sales approach. Unless they charge sponsors varying amounts based on whether they flinch.


UpsideUp - more openly quote start price Euros 3500 going up to Euros 12000 for 50ft cat.


ACS - much more closely guarded suggests it's about $5500 - 7000


The ACS states parts of the system are patented so might be worth searching what exactly the patent is and how it differs from UpsideUP to get some incite into how they actually work.

[AllenRbrts]

An old thread discussing the two options. https://www.cruisersforum.com/forums...ces-66876.html

[thinwater]

Following.


One challenge is that it takes time to unload a sheet from a self-tailing winch. The solution is obvious. Don't leave the rope in the tailing jaws in gusty conditions!!


Install a cam cleat on the bulkhead below the winch and use that in gusty weather. It will release just like a dinghy sheet, with no more effort and in good control. To place the cleat in the sheet, like a dinghy, you need to have the rope coming in, which takes only 10 degrees on the handle.


---


It seems there are two capsize scenarios. The first is wind-only, which happens to racers and also cruisers that don't respect thunderstorms. Reefing works well, and experienced beach cat sailors can fly a hull in a cruising cat with less risk than you think. I've done it for fun, and it probably alarmed people that saw it.



The other case is big waves in storms, and is the one mutihull sailors actually fear, because the exact combination is hard to see coming, and once it comes, often there is little you can do about it. Sailing to windward in big waves, the angle of heel can be high and the windward hull will come out of the water off waves if you are driving hard. A fast sheet release could help. Off the wind is more complicated. Bearing off quickly can help, but if the lee bow buries, you won't be able to bear off (the boat will try to broach). Like sailing a mono with a chute, you have to bear off BEFORE the broach starts, based on what the helmsman sees in the waver, as much as what he can feel. You need to anticipate. Surely, it can be done, but it's probably a complex program, just as it takes years to train a good strong weather off-the-wind helmsman. The rate of yaw caused by passing waves and the helm angle required to counteract are good clues, but they would require boat-specific programming.



The smartest thing a computer could do is alarm and tell you to reduce sail based on motion and AW! And maybe that is actually a smart approach. But the line when broach risk starts can be hard to define.

[tkeithlu]

QUOTE: "The problem with pendulums is that they work best on non accelerating reference frames."

Very true, but damping the pendulum so that it minimally responds to sudden accelerations that reverse quickly is not a difficult design problem.

[CatLove]

Releasing a sheet is not always the way to avoid a capsize or pitchpole.
It depends on the boat , point of sail and obviously wind conditions .
Releasing the jib or genoa sheet is always reducing the pressure but releasing the main may have the opposite effect.
Depending on the gust and boat speed it may be safer to sheet in the main while turning dead downwind. That would depower the main if there's not too much twist in it.

[catsketcher]

A couple of points

Bearing away or heading up is always a good way to reduce pressure on the rig, no matter the situation, offshore or onshore. As long as the autopilot has a wind direction and speed detector then it could be designed to work out how to best cope with a high wind situation for almost all cats.

If the wind direction is less than 90 true (use GPS input to measure true speed and direction) then the boat will be told to head up into the wind. If the direction is greater than 90 true then bear away. In all of my sailing I have never had reason to alter this when sailing powered up skiffs, boards or cats.

The pendulum led to a rotating shelf with cleat has been tried before. I think one real problem is that pendulums can't detect the difference between sway and roll. They both affect the pendulum in the same way. As I have stated before, pendulums are also highly affected by resonance and waves can cause resonance very easily. I would prefer the sensor tell the autopilot what to do, as heading up or bearing away is the first thing I do when I see a massive gust about to hit me. (Although I also like to trim as well). Altering course is the easiest thing to do electronically.

I would also not be too interested in large pendulums considering phones show us what great rate gyros and accelerometers are in common use today. I use the accelerometers in science pracs and they can be used to feed out data. This is similar to what Sean uses in the PyPilot computer.

I also think that the easiest way to dump sheet is to have a snap shackle on the mainsheet at, say, the top of the purchase system. A leash, say about 0.5 - 1m long, is then also attached to the system above the leash. Then when you pull the panic cord the snapshackle releases, the main gets eased 1 metre or so very quickly and then is taken up by the leash, but you still are able to pull it on or ease it some more in the heat of the gust. I can't think of a way to do this for headies but cats usually have large mains and easing these off is pretty important.

I am not that worried about sheet releases for my cat. I have no winch for the main and the sheet is always ready to be released in a cleat (the wishbone keeps loads very light), but I would love to get my PyPilot to talk to the wind instruments when we install the system.

cheers

Phil

[Franziska]

Originally Posted by catsketcher

A couple of points



Bearing away or heading up is always a good way to reduce pressure on the rig, no matter the situation, offshore or onshore. As long as the autopilot has a wind direction and speed detector then it could be designed to work out how to best cope with a high wind situation for almost all cats.



If the wind direction is less than 90 true (use GPS input to measure true speed and direction) then the boat will be told to head up into the wind. If the direction is greater than 90 true then bear away. In all of my sailing I have never had reason to alter this when sailing powered up skiffs, boards or cats.



The pendulum led to a rotating shelf with cleat has been tried before. I think one real problem is that pendulums can't detect the difference between sway and roll. They both affect the pendulum in the same way. As I have stated before, pendulums are also highly affected by resonance and waves can cause resonance very easily. I would prefer the sensor tell the autopilot what to do, as heading up or bearing away is the first thing I do when I see a massive gust about to hit me. (Although I also like to trim as well). Altering course is the easiest thing to do electronically.



I would also not be too interested in large pendulums considering phones show us what great rate gyros and accelerometers are in common use today. I use the accelerometers in science pracs and they can be used to feed out data. This is similar to what Sean uses in the PyPilot computer.



I also think that the easiest way to dump sheet is to have a snap shackle on the mainsheet at, say, the top of the purchase system. A leash, say about 0.5 - 1m long, is then also attached to the system above the leash. Then when you pull the panic cord the snapshackle releases, the main gets eased 1 metre or so very quickly and then is taken up by the leash, but you still are able to pull it on or ease it some more in the heat of the gust. I can't think of a way to do this for headies but cats usually have large mains and easing these off is pretty important.



I am not that worried about sheet releases for my cat. I have no winch for the main and the sheet is always ready to be released in a cleat (the wishbone keeps loads very light), but I would love to get my PyPilot to talk to the wind instruments when we install the system.



cheers



Phil

Phil, do you have some thoughts on this?

Regarding bearing down when a gust comes from behind and you have the mainsheet wide open, do you think it might be helpful (but counterintuitive) to bear away and actually sheet the main as far as possible IN without risking an accidental jibe.
By sheeting in before the gust hits one may actually reduce the exposed main area on a downwind course.

[catsketcher]

I posted on another thread my concerns about this.

Trimming the main on makes the steering much harder and makes you slower. Going slow on a square increases apparent. I prefer to sail faster, reduce apparent and reduce loads and work out what to do with the boat easy to steer. I always have a minute or two but getting the boat onto a square and giving yourself a minute is almost always helpful - unless you have a Twiggy.

The Twiggy was a Crowther tri I used to own. Once I got hit by a sudden westerly and I did what I had learnt to do and ran downwind. The Twiggy had too narrow bows and she went bow down and I started scooping water over the bows. It was not nice. I then went to head up to drop the main and on a broad reach she became nice and bow up as the load went on the floats.

So if you are on a very wide tri, be careful of bearing away onto a square to get some time in a squall - but better to not buy a Twiggy for cruising fast anyway. Nice boats, just a serious defect with bow volume. But a square should be fine for a few minutes in a squall for a well balanced cat.

[rob denney]

Originally Posted by Franziska

Thanks Rob following your interesting project for some time. Exciting stuff.

Thanks. It's huge fun, lovely people, great place and a project that is likely to make a difference.

Originally Posted by Franziska

Would be interesting to see your simple system once it's working. Do you think it could be implemented/retrofitted on a typical cruising multi?

The pitch/heel mechanism could be, the foolproof sheet release would need a fair bit of messing about.

Originally Posted by Franziska

Freestanding masts are great. Love the simplicity.
Especially on a mono, tri or proa. On a cat unfortunately less so.
Unfortunately most of us are stuck with what the boat has already. Rerigging for a new type of rig is usually not cost effective...

They needn't be if designed from the beginning.

Originally Posted by Franziska

Unfortunately most of us are stuck with what the boat has already. Rerigging for a new type of rig is usually not cost effective...

True for weekending but well worth it if you are planning on sailing offshore for the stress reduction alone. Add in the other benefits and it is a no brainer.

[rob denney]

Originally Posted by catsketcher

I think that Sean and Rob are probably onto the easiest way to implement a system - bear the boat away or round it up in an emergency manner under autopilot.

Sorry if I wasn't clear, but that is absolutely not what I said, or recommend. Especially for "90% of the time on autopilot" people. By the time you have got to the helm you will have little to zero time to figure out which way to steer. Expecting the autohelm to figure it out and act accordingly and in time is a big ask.

Luffing and bearing away are fraught. Luffing adds centrifugal force to the heeling which is bad enough. Worse, you can end up in irons and will have strife with the cleated headsail. Bearing away can easily send you screaming down a wave and into the one ahead. And/or you accidentally gybe with all the associated dramas.
Trimming the main on and turning downwind is an option, but you are unlikely to have enough time to do so in a squall. If the helm screws it up, you are custard. If the squall doesn't abate, you have a pretty serious problem lowering the main.

By far the best solution is not to get in these situations. Many cruisers sail undercanvassed at night or in squally weather, which is boring and slow and still results in dramas if the squall is strong enough.
If you do get caught out, the least stress solution is to depower the boat completely, stop and quietly drift. Unfortunately, this is impossible with stayed rig multis. Dumped headsails and their sheets flog, shaking the whole boat, the mainsail gets pinned against the shrouds or flogs and steering becomes difficult as you have no speed, but must keep control. Any extras become a nightmare, especially if they don't furl properly.
These scenarios usually happen at 3 am with associated rain, change of wind direction and half asleep crew. They are rare, but only have to happen once to spoil your trip. What is not rare is worrying about them, which really should not be a part of an enjoyable cruise when the solution is so obvious.

[catsketcher]

Again Rob, we disagree. You may remember that I spent many years of my life racing Lasers and although I loved sailing the Laser I never wanted a free standing rig for my own cruiser. I have always been happy to have 8 stays holding up my own mast for 22 years so far and I don't think many people will find the limitations of a free standing rig (lack of extras, inability to fine tune luff curve, extra bending, increased mast stress) worth the benefits. That said, I broke more masts when Laser sailing than all my other sailing combined.

As for the described situations, again I don't concur. Every time I have been caught out in a big blow, altering course is the very first thing I do. You have to do it well but it should not be super hard to tell an autopilot to bear away to 150 true or head up to 60 true, depending onyour intial course. If you are in a squall then there will be few waves, so screaming down a wave will not occur, not for many minutes, whcih will give you time to react. If there are already bug waves then you will have reduced sail up and heading up or bearing away will not be fraught.