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The Death Zone


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#1 IshmaelHatesThatDamnWhale

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Posted 11 May 2013 - 04:17 PM

Following the Artemis AC72 capsize there has been a lot of talk about the "death zone" by a lot of people who don't seem to have a clue what it's all about.  The death zone is the transition during the bear away from going upwind to downwind on an ultra-high performance boat like a beach cat, skiff, or AC72.  The reason this is know as the death zone is because when a really fast boat bears away, the apparent wind speed increases a huge amount, putting a large load on the sails and foils as the boat accelerates like a mofo.  The sail plan also tries to push the bow down during the bear away, hence the reason why skiffs and multis tend to pitch pole during the bear away.  The key to a good bear away is getting through the death zone as quickly as possible, but the driver and trimmers need to be on the same page.  It's not like a keel boat or even a dinghy where you just ease the sheets and turn.  The death zone is also very hard (nearly impossible) to sail in on a skiff.  They do not like to jib reach, plain and simple.  You either get to go upwind or downwind, otherwise there is too much apparent windspeed and not enough stability (mostly speaking from Aussie 18s), ending in either a pitch pole or digging a rack and cartwheeling.  Long story short, anyone who thinks that a bear away in 25 knots on a high performance boat should be as simple as just turning doesn't have a clue.  Here is a quick video from my friends on a 1994 Grand Prix Aussie 18 failing at a bear away.  That particular boat is a major PITA to sail because it has massive racks and "rack runners" to support them.  You can see the mainsail hitting the runners, which helped seal their fate.  With all this said, I'm going to go sail an 18 today in honor of a great sailor who lost his life on the cutting edge of this sport.

 



#2 TheFlash

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Posted 11 May 2013 - 04:34 PM

and an I14 going down the mine.  Notice how high some of the boats are going around the offset mark. They do it specifically to avoid the "zone"

 

 

14 Pitchpole


#3 BalticBandit

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Posted 11 May 2013 - 05:59 PM

Well its not so much that there is "too much apparent wind" in the "death zone" (ie close reach) on a skiff, it is more that the changes in AWA due to transitioning in and out of puffs at roughly every 2-3 seconds are so great, its almost impossible to trim to.  Thus it is very easy to end up overtrimmed (pitchpole) or undertrimmed (teabagged) .   Obviously Teabagged is preferrable, so you will see a lot of skiff skippers do exactly that in the bearaway lest they go the other way since a slight teabag can be recovered.    But in these monster cats, that's not really an option so you gotta stay ontop of the trim at a rate that is essentially impossible to do



#4 Mark K

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Posted 11 May 2013 - 07:43 PM

 I don't think you can trim a way around it. What might work is spoilers. 



#5 Grrr...

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Posted 11 May 2013 - 07:45 PM

But in these monster cats, that's not really an option so you gotta stay ontop of the trim at a rate that is essentially impossible to do

 

Really?  Impossible?

 

Funny.  You better tell the sailors that, because I'm pretty sure that they've done it on 72's and their smaller cousins hundreds and hundreds of times.

 

Top Fuel dragsters are inherently unsafe.  Wingsuits are inherently unsafe.  Base jumping is inherently unsafe.  Hell, judging by the serious injuries that have been incurred, Football and Hockey are inherently unsafe too.  So is mountain climbing.  Yet people continue to perform all those unsafe activites because they love them.

 

Back to the original post, I agree sailing will never be mainstream.  That's no reason not to push as hard as we can to reach the technological pinnacle of the sport.  But an uninformed article by someone who is clearly trying to overstate the point using terms he doesn't fully understand is really pretty pointless.



#6 mustang__1

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Posted 11 May 2013 - 07:46 PM

the other factor is that any leeward heel is going to essentially cause the rudder to create positive lift - effectively lifting the transom and creating downpressure on the bow. i dont know how you deal with that on a multi... the trick to the bear away is that it needs to be right. its not necessarily a matter of doing a bat turn to get downwind quick so much as it is timing the waves and the trim and the acceleration.  



#7 rgscpat

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Posted 11 May 2013 - 07:47 PM

Is it even possible to re-design bows so that they are less likely to dig in and trip the boat without changing their wave-cutting character or slowing the design? 

 

Is it possible to instrument the AC72 hulls to learn more about what stresses they're seeing?



#8 mustang__1

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Posted 11 May 2013 - 07:52 PM

Is it even possible to re-design bows so that they are less likely to dig in and trip the boat without changing their wave-cutting character or slowing the design? 

 

Is it possible to instrument the AC72 hulls to learn more about what stresses they're seeing?

the best solution would be T-foil rudders. I seem to recall reading that the rule explicitly disallows them, though? 



#9 TheFlash

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Posted 11 May 2013 - 08:01 PM

yep, no movable foils on the rudders



#10 ؏ΩӁقڝӃڜ Җ

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Posted 11 May 2013 - 08:15 PM

Bearing away in a good breeze. Bows dig in. Boat slows. Rig loads up. Catastrophic beam failure (seems like that was how it happened).

 

Time to de-tune the boats to be able to handle such conditions. Be it smaller wing masts - or maybe back to soft rigs. Increased scantlings, construction specs. Stronger (and heavier) boats as a result. Boats will be slower but less chance of disaster. 

 

Time for the AC guys to do it before the government steps in and somebody who knows nothing about sailing makes the rules - at least for the US.

 

This is where the "gung-ho" "blood & guts" wankers step in and flame the idea.



#11 Mark K

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Posted 11 May 2013 - 08:30 PM

 Spoilers. Maybe only the upper third of the wing. 



#12 billy backstay

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Posted 11 May 2013 - 09:05 PM

Is it even possible to re-design bows so that they are less likely to dig in and trip the boat without changing their wave-cutting character or slowing the design? 

 

Is it possible to instrument the AC72 hulls to learn more about what stresses they're seeing?

 

 

Probably, look at al the sensors on F1 cars.  But I don't think you can depower a wing like you can blow the sheet on a fabric mainsail or kite?



#13 Pete M

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Posted 11 May 2013 - 09:20 PM

"Following the Artemis AC72 capsize there has been a lot of talk about the "death zone" by a lot of people who don't seem to have a clue what it's all about."

thanks Ishmael, I was going to write something myself.

in the days before the Bieker T-foil, the International 14 was nearly impossible to turn downwind in big conditions. we would sail upwind way past the top mark waiting for a lull. One time the Columbia river nearly killed me - we never did get to the bottom mark after a capsize on the downwind.

but I always heard it called "zone of death"

#14 haligonian winterr

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Posted 11 May 2013 - 10:52 PM

I agree that the boats need to be stronger, although I don't necessarily agree that this should be an example. The article states (as much as I hate to say that) that Artemis had already had issues with that beam, and other structural components.

I think the teams are more than capable if testing loads and building to those loads, but everyone makes mistakes and not every second of sailing can be predicted by a load cell.

Do I think we should wait until more sailors die to beef up the boats? Hell no. I think they should beef up the boats so the sailors don't have to worry about breaking a spar while trying to sail the course (or train).

0.02c

HW

Bearing away in a good breeze. Bows dig in. Boat slows. Rig loads up. Catastrophic beam failure (seems like that was how it happened).
 
Time to de-tune the boats to be able to handle such conditions. Be it smaller wing masts - or maybe back to soft rigs. Increased scantlings, construction specs. Stronger (and heavier) boats as a result. Boats will be slower but less chance of disaster. 
 
Time for the AC guys to do it before the government steps in and somebody who knows nothing about sailing makes the rules - at least for the US.
 
This is where the "gung-ho" "blood & guts" wankers step in and flame the idea.



#15 ؏ΩӁقڝӃڜ Җ

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Posted 11 May 2013 - 11:00 PM

A successful yacht designer and professor of aeronautics, once told me that in spite of all the ways & means of measuring loads on structures such as aircraft and yachts, there will always come a time when a load previously unexpected will be applied - somewhere. More particularly applies to sailing.

 

PS. With aircraft there is a safety margin by legislation. Not so with boats where the attitude is still what Ben Lexen stated- "If it doesn't break, it's too heavy. If it does break, it wasn't strong enough"



#16 Racerdave

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Posted 11 May 2013 - 11:49 PM

With all due respect to Webb Chiles I do not think he has any current sailing exprience that would apply to anything like an AC 72/ 45, I-14 etc so he can STFU any time now.  Anyone who wants  to know about sensors and datalogging on the big cats and tri's should go review some back issues of Seahorse lots of good information there from the Oracle program last cup series. As for spoilers on a wing rig one of the by-products of spoilers is drag.....it would be interesting to see what the vectors look like  in a wing sail vs. aircraft scenario. Speaking with someone who has done some sailing on the AC cats and Tri  it was mentioned that one is very cognzent of the load paths and that some places on  the boats are safer then others. . . .RIP "Bart".



#17 fastyacht

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Posted 12 May 2013 - 12:04 AM

Bearing away in a good breeze. Bows dig in. Boat slows. Rig loads up. Catastrophic beam failure (seems like that was how it happened).

 

Time to de-tune the boats to be able to handle such conditions. Be it smaller wing masts - or maybe back to soft rigs. Increased scantlings, construction specs. Stronger (and heavier) boats as a result. Boats will be slower but less chance of disaster. 

 

Time for the AC guys to do it before the government steps in and somebody who knows nothing about sailing makes the rules - at least for the US.

 

This is where the "gung-ho" "blood & guts" wankers step in and flame the idea.

 

When did the govmt step into NASCAR or F1 or Indy?  Why would they need )or want!) to step into this?????



#18 bruno

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Posted 12 May 2013 - 01:51 AM

As has been pointed out before, these boats are not inherently deadly, other than being quite fast and having powerful platforms. What makes them deadly dangerous are the weight and moveable appendage rules in particular, the rules in general. Now that we have seen a tragedy there may need to be a rethink but that would inherently change the playing field in someone's favor.

Look at the uproar recently over adding legs: conspiracy, dirty trick, as bad as Bertarelli, scoundrels, etc.,. Given that it was M&M and TNZ who have stretched (in what should have been a predictable path) the rules to include fully foiling, which they were designed to prevent AFAIK, then complained about being disadvantaged by any underhanded rules changes, one has to wonder what will be their position as the opinion leader amongst the challengers.

What probably would prevent some of last week's mayhem would have been to have allowed four controllable lfting appendages at all times and required heavier scantlings and rigs. There will never be a safety guarantee but this would change the envelope away from impossibly difficult (perhaps) to race in full on Sf conditions (what if they actually had a dozen contenders fleet racing up cityfont, imagine that for a monment, all thos who decry the lack of participants) to more controllable but still exciting racing.

But that might cause delays, and any change will benefit some more than others. And there is no preventing bad judgement or engineering in a development class like this. But it might reduce some of the uncontrollable moments.

#19 ؏ΩӁقڝӃڜ Җ

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Posted 12 May 2013 - 05:05 AM

Bearing away in a good breeze. Bows dig in. Boat slows. Rig loads up. Catastrophic beam failure (seems like that was how it happened).

 

Time to de-tune the boats to be able to handle such conditions. Be it smaller wing masts - or maybe back to soft rigs. Increased scantlings, construction specs. Stronger (and heavier) boats as a result. Boats will be slower but less chance of disaster. 

 

Time for the AC guys to do it before the government steps in and somebody who knows nothing about sailing makes the rules - at least for the US.

 

This is where the "gung-ho" "blood & guts" wankers step in and flame the idea.

 

When did the govmt step into NASCAR or F1 or Indy?  Why would they need )or want!) to step into this?????

 

AC isn't NASCAR and you don't have F1 over there.

 

Didn't the CG "step in" after the Low Speed Chase incident?

 

Of course you can carry on as if nothing happened, but don't whinge if they do get involved.



#20 BalticBandit

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Posted 12 May 2013 - 09:55 AM

CG has authority because LS Chase racing was essentially operating in that grey area between COLREGS and RRS.  But in the USA you can pretty much contract away any liability due to risk.  And yes there is F1 racing in the USA.  Same risk

 

As for instrumenting these things - well DogZilla embedded linear strands of optical fiber into the composite and using laser interferometry they were able to look at the loads in various parts of the hull in real time with onboard PLCs.  And they have a "warning bell" as to when the safety margin was being exceeded.   And I remember the discussion about how they were driving the boat so that the "warning bell" was going off between 30% and 50% of the time.

 

Given the folks involved in the Artemis program I would be very surprised if they don't have similar structural instrumentation.  The gotcha is that in certain loading conditions you will go from "just inside the safety margin" to "snap" fairly quickly. 

 

Part of what has not been pointed out about "the Zone of Death" is that part of why it is called that is that once you initiate the bearaway you don't effectively don't have the option to bail out of the maneuver because if you try, the AWA comes aft very fast and dramatically increases heeling forces  And the attempt to turn to weather does the same thing, almost guaranteeing a crash.   So the only option is to continue the bearaway and hope you don't pitch pole.

 

So if in such a circumstance the "Warning bell" goes into "the red zone" - you really don't have any choice but to hope the hull stays together.  And in this case it did not.  



#21 Ned

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Posted 12 May 2013 - 10:00 AM

and an I14 going down the mine.  Notice how high some of the boats are going around the offset mark. They do it specifically to avoid the "zone"

 

I am pretty sure I own that boat now.  It is exactly evil in the Zone of Death.



#22 AJ Oliver

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Posted 12 May 2013 - 04:52 PM

I day-sailed on a big catamaran (80 ft or so) called at that time "On the Edge" in NZ a while back.  It had huge sail area, and had been built originally for long distance racing.  The Skipper said they never jibed it - did a "chicken Jib" (tack through 270 degrees) instead.  

http://www.youtube.c...h?v=J3BLiNNcBno

I think it is in Australia now. 

In a really honking wind, I sometimes Chicken Jibe my own boat too because, with my low budget program, I cannot afford much in the way of expensive repairs.  

This may well not be relevant for AC or racing sport boats - if so, sorry for the thread drift.  

But you can almost always avoid bearing away in the "death zone" if you really want to.  



#23 Pete M

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Posted 12 May 2013 - 05:01 PM

"But you can almost always avoid bearing away in the "death zone" if you really want to."

Um no

the zone of death is basically when on a 2 sail beam reach.

you must go thru the zone when turning from upwind to downwind.

#24 ؏ΩӁقڝӃڜ Җ

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Posted 12 May 2013 - 08:03 PM

CG has authority because LS Chase racing was essentially operating in that grey area between COLREGS and RRS.  But in the USA you can pretty much contract away any liability due to risk.  And yes there is F1 racing in the USA.  Same risk

 

CG has the authority ---- and if they choose to act there isn't a damn thing you can do about it.

 

It makes sense to be seen by them as "self regulating". If the AC people "self regulate" then the CG will likely leave them to it. If the AC folks do nothing then the CG might step in, and it might be that the only way the AC could go ahead is to take it to a another country.



#25 Torsten

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Posted 13 May 2013 - 12:35 AM

Pardon my ignorance, but what's a spoiler and how do they work?



#26 mustang__1

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Posted 13 May 2013 - 12:44 AM

spoilers on airplanes are the flaps that pop up when you land. They stop the wing from flying. Mark may have a point, and, while i doubt it would work in all cases, it could be useful in that they would spoil the air flow at the top of the wing so it stops working (as opposed to twisting off, which creates more forward, downward, pressure) to allow it turn down easier. 



#27 Mark K

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Posted 13 May 2013 - 02:32 AM

 It's would be possible to have them in a much more effective location on a wing sail than an aircraft wing, no control issues.

 

They could be further forward, ideally right up in the nose (see horn-shaped icing), but it would certainly be easier at the main spar.  4-6" air dams of thin kevlar or carbon sliding up out of slots, straight up, or canted forward a bit maybe?  I dunno...



#28 NoStrings

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Posted 13 May 2013 - 05:29 AM

CG has authority because LS Chase racing was essentially operating in that grey area between COLREGS and RRS.  But in the USA you can pretty much contract away any liability due to risk.  And yes there is F1 racing in the USA.  Same risk

 
CG has the authority ---- and if they choose to act there isn't a damn thing you can do about it.
 
It makes sense to be seen by them as "self regulating". If the AC people "self regulate" then the CG will likely leave them to it. If the AC folks do nothing then the CG might step in, and it might be that the only way the AC could go ahead is to take it to a another country.

You ever see the USCG involved in the design of offshore powerboats? NO. Now please stfu about the USCG stepping into this process.

#29 ؏ΩӁقڝӃڜ Җ

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Posted 13 May 2013 - 05:40 AM

'

 

CG has authority because LS Chase racing was essentially operating in that grey area between COLREGS and RRS.  But in the USA you can pretty much contract away any liability due to risk.  And yes there is F1 racing in the USA.  Same risk

 
CG has the authority ---- and if they choose to act there isn't a damn thing you can do about it.
 
It makes sense to be seen by them as "self regulating". If the AC people "self regulate" then the CG will likely leave them to it. If the AC folks do nothing then the CG might step in, and it might be that the only way the AC could go ahead is to take it to a another country.

You ever see the USCG involved in the design of offshore powerboats? NO. Now please stfu about the USCG stepping into this process.

These are NOT offshore powerboats you fucking moron!

 

Are you so bloody stupid that you don't think the authorities might ask questions when somebody dies?

 

Anybody but a fucking wanker like you are demonstrating you are, would think "If we show we are "self regulating" here then the authorities won't step in and make the rules for us". Are you that stupid?

 

It did happen with the Low Speed Chase" incident did it not? Did the CG not step in with extra requirements for similar races?



#30 NoStrings

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Posted 13 May 2013 - 05:57 AM

The fact of the matter is that the USCG had NO AUTHORITY to keep us from racing. The best they could do is withhold approval of our permits, knowing that our local OA would acquiesce due to insurance considerations. The truth is that there is still a lot of residual ill will over the USCG actions. On the upside, that action did serve as a forcing function of sorts, causing the local OAs to standardize procedures, Mel's, etc.

That said, what they absolutely DID NOT GET INVOLVED IN was the determination of which sailboat designs were to be permitted to race offshore, or what our equipment lists should be. Why not? Because OUR equipment requirements at their most sparse are orders of magnitude greater than those imposed by the USCG.

Now regarding offshore powerboat racing...they actually break up and hurt people on a fairly regular basis, yet the USCG doesn't involve themselves in boat design as you suggest they will do here. So get your head out of your dark ass and try to offer something constructive. What you know about racing on SF Bay or the LSC incident (that you perversely seem to have taken ownership) can easily fit in a thimble.

As for calling me names...I'd have to tie my brain behind my back to make arguing with you even remotely fair.

#31 BalticBandit

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Posted 13 May 2013 - 07:06 AM

hmm more dangerous than the below?

 

But yes the USCG could shut down your racing.  The port is a strategic port and the commander of the port can basically tell you you cannot leave the dock and can send US Marshalls down to arrest your boat.  Its a bit more complex than that legally but they COULD do it.  They won't but they could



#32 ؏ΩӁقڝӃڜ Җ

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Posted 13 May 2013 - 09:08 AM

The fact of the matter is that the USCG had NO AUTHORITY to keep us from racing. The best they could do is withhold approval of our permits, knowing that our local OA would acquiesce due to insurance considerations. The truth is that there is still a lot of residual ill will over the USCG actions. On the upside, that action did serve as a forcing function of sorts, causing the local OAs to standardize procedures, Mel's, etc.

That said, what they absolutely DID NOT GET INVOLVED IN was the determination of which sailboat designs were to be permitted to race offshore, or what our equipment lists should be. Why not? Because OUR equipment requirements at their most sparse are orders of magnitude greater than those imposed by the USCG.

Now regarding offshore powerboat racing...they actually break up and hurt people on a fairly regular basis, yet the USCG doesn't involve themselves in boat design as you suggest they will do here. So get your head out of your dark ass and try to offer something constructive. What you know about racing on SF Bay or the LSC incident (that you perversely seem to have taken ownership) can easily fit in a thimble.

As for calling me names...I'd have to tie my brain behind my back to make arguing with you even remotely fair.

 What the hell do you think that is if not "stepping in" and interferring?

 

Who said anything about designs - I didn't. Seems your imagination is running wild.

 

Your brains are already behind your back, in your shorts - shit for brains.



#33 PBO

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Posted 13 May 2013 - 09:54 AM

Although this is a terrible thing to say now & I don't want to sound disrespectful toward Andrew Simpson - his death will increase the interest in AC because of the (now?) perceived danger. This is a large part of the attraction to motorsport for many spectators, it's probably the morbid thrill of seeing someone crash... the inherent danger. No one would show any interest in watching electric golf buggies race after all, the perceived risk is so slight that it's may as well no exist

 

I've had my own experience with bear away crashes & prone gybes, been caught under neath, tangled in the sheets. Scary, sobering experience & I know someone who had a worse experience than I did. It didn't stop me taking the risk & a not so small part of me craving the adrenaline of surviving. I imagine that is shared by every AC sailor on board in fresh conditions

 

As inappropriate as it may be - I think the development classes need to keep pushing the envelope. The people who sail them, let's be honest aren't there under duress, they know the risks. Accidents are common, unfortunate & overwhelmingly sad deaths are fortunately rare



#34 Tucky

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Posted 13 May 2013 - 01:04 PM

I day-sailed on a big catamaran (80 ft or so) called at that time "On the Edge" in NZ a while back.  It had huge sail area, and had been built originally for long distance racing.  The Skipper said they never jibed it - did a "chicken Jib" (tack through 270 degrees) instead.  

http://www.youtube.c...h?v=J3BLiNNcBno

I think it is in Australia now. 

In a really honking wind, I sometimes Chicken Jibe my own boat too because, with my low budget program, I cannot afford much in the way of expensive repairs.  

This may well not be relevant for AC or racing sport boats - if so, sorry for the thread drift.  

But you can almost always avoid bearing away in the "death zone" if you really want to.  

To stay on topic a little, what you are describing requires going through the "death zone" twice- gybing is not a "death zone" problem.  A chicken gybe requires that a boat  (given your 45 degree off DDW) head up through the zone to tack and then bear away through the zone after the tack. My guess is that the big cat you sailed on had a pitchpole problem when sailing deep.



#35 MauganNacra20

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Posted 13 May 2013 - 03:00 PM

Hrm

 

Lots of talk about "Zone of Death" by skiffies here but I don't see a lot of talk about what its like on a cat.

 

You see we don't call it the "Zone of Death" since we actually SAIL in that "zone".  We call it "No man's land" since when you're there, neither bearing off or heading up will save you.  The only thing you can do to keep things from going pear shaped is adjust the sails.  I know from sailing with my buddy Bailey who came from the SF Bay Skiff scene, that the skiffies try to get through the beam reach zone as quickly as possible and don't actually stay there.

 


Many of the newer designs of cats don't reach as well as the old Hobie 16 with its banana hulls.  My Nacra 20 beam reaches like a banshee and it a buttload of fun to sail - but its because the Nacra 20 has a bouyancy to spare in the bows.  In fact, I've never actually pitchpoled my N20.  Buried her up to the beam a couple of times but never went over due to a pitchpole.



#36 EarthBM

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Posted 13 May 2013 - 04:53 PM

It's an engineering problem, not some philosophical "sailing is meant to be safe and romantic" problem. We should all be GRATEFUL to the AC effort and to Andrew Simpson for expanding our knowledge of what it takes to build and operate machines like these. There undoubtedly were critics (but luckily no nanny government to empower them) saying that humans aren't meant to fly in the air 100 years ago, and look where we are now.

ORMA 60 were modified with longer waterline/beam ratio to give us MOD70s. 2nd boats of AC72 campaigns are better than 1st. Humans learn. AC35 boats will be even better. We have Andrew Simpson and others to thank for that.

Just like you size the canvas you carry on multihulls for gusts, you can deal with the "death zone" constructively.

#37 captain horizon

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Posted 13 May 2013 - 05:26 PM

I may stand corrected on this but I think the term"zone of death" was first coined by ice boaters. The acceleration of a DN or Skeeter is unbelievable rounding the weather mark. On a DN you can accelerate from an upwind speed of 30-35 mph to over 60mph downwind in a matter of seconds.
Getting through the zone can virtually suck you out of the boat with the G forces of that turn.
Getting through the zone on any multihull in breezy conditions can be a tough maneuver. The acceleration on my ACat is not as dramatic as a DN but every bit as tense.

#38 Mark K

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Posted 13 May 2013 - 06:52 PM

  Just in my mind: It's the the zone where if you get overpowered, you don't know whether to head up or bear away.

 

  Probably won't matter anyway....you just like to think it does....



#39 Bill Gibbs

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Posted 13 May 2013 - 08:03 PM

Basically MaugonNacra20 & Mark K have the multi-perspective right.
 
Wave piercing/low buoyancy bows work much better on small cats where crew weight is an effective/fast bow trim option.  Safe big cats need more buoyancy up front.
 
No-mans land is the better term.  Sail higher and you can head up in a puff, sail lower and you can fall off in a puff.  From a beam reach it's a long way in either direction to depower and probably ineffective & dangerous to try.  Better to trim out.  Since this is many cats fastest point of sail, it is to be enjoyed, not avoided.  Hull flying on a beam reach is all sail trimming.  A lateral capsize is the normal danger.
 
PItchpole danger usually occurs sailing downwind fast, gybing thru 90 degrees or less.  Falling off in puffs to depower.  As the wind increases, the gybe angle decreases, until there is nowhere to fall off to.  Sail loads exceed bow bouyancy and oops.  If you are only watching AWA and AWS, you can be in for a nasty surprise.  AWS is greatly diminished by boat speed.  Waves (or anything that slows your boat) are a common pitchpole factor.  Bury the bows into a wave back surfing deep, boat slows, inertia rotates the bows down, wind clocks aft and builds as AWS grows to TWS.  Heck of a way to find its really blowing 30+.  Way past time to have reduced sail.  Dumping the headsail early helps.  If you avoid the pitchpole and are releaved, you might miss that your boat is now rounding up (massive weather helm as only the main is drawing and no flow for rudders) into a lateral capsize.  Time to dump the main .
 
Any multi can be sailed downwind into a pitchpole at some wind strength and sea state.  In extreme conditions it is unavoidable under bare sticks.  Any multi can be sailed into a lateral capsize.  The crew keeps a multi safe. 
 
If Artemis broke first causing the crash, then it wasn't crew error.  Usually capsizes are crew error.
 
This accident does highlight why "capsizing" cannot be an acceptable part of large multi-racing.  What's fun on a beach cat doesn't scale up safely.

#40 EarthBM

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Posted 13 May 2013 - 09:21 PM

Dumping the headsail early helps.  If you avoid the pitchpole and are releaved, you might miss that your boat is now rounding up (massive weather helm as only the main is drawing and no flow for rudders) into a lateral capsize.  Time to dump the main .


Excellent post. Dumping the main sheet helps too though. Yes it will be pushed against the sidestays so won't depower right away, but because the boat will round up without a headsail, eventually the main will depower too. Happened to me at Cape Mendocino.

#41 Bill Gibbs

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Posted 13 May 2013 - 09:51 PM

Dumping the headsail early helps.  If you avoid the pitchpole and are releaved, you might miss that your boat is now rounding up (massive weather helm as only the main is drawing and no flow for rudders) into a lateral capsize.  Time to dump the main .


Excellent post. Dumping the main sheet helps too though. Yes it will be pushed against the sidestays so won't depower right away, but because the boat will round up without a headsail, eventually the main will depower too. Happened to me at Cape Mendocino.

I have experienced these situations too, did the wave nose plant on the back side of Santa Cruz island, did the round-up after hitting a kelp island off Pt Dume.  Survived both, but they leave memories.  Or should I say lessons?



#42 Life Buoy 15

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Posted 13 May 2013 - 10:06 PM

Bearing away in a good breeze. Bows dig in. Boat slows. Rig loads up. Catastrophic beam failure (seems like that was how it happened).
 
Time to de-tune the boats to be able to handle such conditions. Be it smaller wing masts - or maybe back to soft rigs. Increased scantlings, construction specs. Stronger (and heavier) boats as a result. Boats will be slower but less chance of disaster. 
 
Time for the AC guys to do it before the government steps in and somebody who knows nothing about sailing makes the rules - at least for the US.
 
This is where the "gung-ho" "blood & guts" wankers step in and flame the idea.

 
When did the govmt step into NASCAR or F1 or Indy?  Why would they need )or want!) to step into this?????
One would hope they would deal with the gun issue first.

#43 Mohammed Bin Lyin

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Posted 14 May 2013 - 02:50 AM

Following the Artemis AC72 capsize there has been a lot of talk about the "death zone" by a lot of people who don't seem to have a clue what it's all about.  The death zone is the transition during the bear away from going upwind to downwind on an ultra-high performance boat like a beach cat, skiff, or AC72.  The reason this is know as the death zone is because when a really fast boat bears away, the apparent wind speed increases a huge amount, putting a large load on the sails and foils as the boat accelerates like a mofo.  The sail plan also tries to push the bow down during the bear away, hence the reason why skiffs and multis tend to pitch pole during the bear away.  The key to a good bear away is getting through the death zone as quickly as possible, but the driver and trimmers need to be on the same page.  It's not like a keel boat or even a dinghy where you just ease the sheets and turn.  The death zone is also very hard (nearly impossible) to sail in on a skiff.  They do not like to jib reach, plain and simple.  You either get to go upwind or downwind, otherwise there is too much apparent windspeed and not enough stability (mostly speaking from Aussie 18s), ending in either a pitch pole or digging a rack and cartwheeling.  Long story short, anyone who thinks that a bear away in 25 knots on a high performance boat should be as simple as just turning doesn't have a clue.  Here is a quick video from my friends on a 1994 Grand Prix Aussie 18 failing at a bear away.  That particular boat is a major PITA to sail because it has massive racks and "rack runners" to support them.  You can see the mainsail hitting the runners, which helped seal their fate.  With all this said, I'm going to go sail an 18 today in honor of a great sailor who lost his life on the cutting edge of this sport.

 

 

Crew error caused that capsize, 18 ft skiffs can 2 sail shy reach, in a NE on Sydney harbour the ride from the finish to the SFS is a 2 sail shy reach and most of my crews reckon it was one of the best rides of the day.

A lazy sheethand makes 2 sail reaching difficult, look for the gusts so they dont hit you by surprise.

 

Sometimes when you can see you are not going to carry the kite you 2 sail reach for a bit of height before setting the kite so you can make it, otherwise you carry it as far as you can and when the angle is good you drop it and 2 sail reach the rest of the way

 

The video-

Forward hand sits on the net while the boat is overpowered, the sheethand has a few handfuls of sheet in reserve so the crew should be on the wire, they even call him out.

 

Why is the forward hand not holding the jib sheet, how can he ease it on the bear away if he is not holding it?

The forward hand should have the jib sheet in his hand at all times when overpowered, you can dump the main and still be put in by the jib in big gusts.

 

Bear away in an 18

Ease the vang (did they do this in the video?)

Move to the aft limit of the wing.

Look for waves that could be a problem,go before or after wave, look for gust and if one is approaching do it before the gust hits or wait for it to hit before bearing away.

The forward hand trims jib perfectly on bear away the jib helps pull the bow around if it is trimmed properly while sheet dumps main as skipper turns boat, crew run in before they get wet.

 

Death zone? fucking pussies!



#44 Life Buoy 15

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Posted 14 May 2013 - 07:28 AM

Oh yeah? Watch this you heroes....



#45 Kapteeni Kalma

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Posted 14 May 2013 - 10:04 AM

Safety device that does not favor any particular team would be this: the cats tow behind a deployable sea anchor/brake or two, attached at the stern. This brake prevents pitchpoling and gives couple more seconds to depower the wing.



#46 linaszuk

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Posted 14 May 2013 - 02:23 PM

's why i like my 4-knot-shitbox - no such issues.



#47 BalticBandit

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Posted 14 May 2013 - 02:38 PM

Well that was kinda the comment of that one offshore sailor.  That any boat with a "zone of death" should not be raced...  but that kinda ignores the point



#48 bruno

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Posted 14 May 2013 - 05:56 PM

right, skiffs can reach in breeze if well rigged and sailed, similar to a multi, pay attention to sheets, trim as required to stay on your feet and keep going, after a while you get a rhythym, which is actually dangerous if you get too comfortable, relax too much. tmfoil rudders help alot.

#49 IshmaelHatesThatDamnWhale

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Posted 15 May 2013 - 03:11 AM

Yes, it is certainly possible to sail skiffs and multis in the zone if you have flat water and fast, active trim.  Multihulls obviously 2-sail reach better since if you ease the sails a lot the boat is stable on both hulls while on a skiff the whole crew is in the piss if you over-ease in a puff.  You can also be on a 2-sail reach and be below the zone.  The video I posted was just an example of a boat going through the zone, obviously they didn't do everything right because they went for a swim.  Since all my skiff sailing has been on SF Bay, which is known for it's gnarly chop on an ebb tide, we don't like to 2-sail reach and try to only bear away when there is a patch of flat water or lull.  If you watch videos from the Aussie 18 regatta held at Crissy Field in the late summer you will see even the top boats sailing way past the weather mark waiting for an opportunity to bear away.

 

Anyway the whole point of this thread was to explain that all fast boats experience the "death zone" or "zone of death" or whatever you want to call it and that is just part of the nature of the beast.  I wasn't trying to stir up shit with the loss of Andrew Simpson on the Artemis AC72 or debate whether multis or skiffs 2-sail reach better.



#50 BalticBandit

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Posted 15 May 2013 - 03:20 AM

I think your point about over-easing not being catastrophic on a Multi is very apt and part of why Multi's can sail in this zone better than skiff's can.  Because if you are cycling through puff/lull cycles in 3-5 seconds but can afford a slight "oops" on one side, you have a more trimmable situation than you have when you have to stay on the knife edge the whole way.



#51 Bill Gibbs

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Posted 15 May 2013 - 10:28 AM

Yes to the multi more stable reaching, and a big multi more so

#52 Tailwind

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Posted 15 May 2013 - 09:01 PM

Ice boaters have been dealing with the death zone for about 150 years. Here's what it looks like on a stern steerer when things go bad.

 

 

There's a slightly different technique for every ice boat and I'm sure it's as unpredictible and difficult to master on a soft water boat travellign at ice boat speeds too.



#53 TornadoCAN99

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Posted 15 May 2013 - 11:29 PM

Sailing is inherently a risky activity. Always has been, always will be. There are deaths on slow boats as well as fast, mono or multi. For those clamoring to make the AC class safer, where was the similar outcry for the keelboat racers killed only last year on the rocks racing off SoCal & Mexico? Due to a rudder failure, wasn't it?

 

How many skiff sailors have died over the years by getting entangled in the rigging following a capsize? The Tornado fleet had a few top Olympians lost this way. Were changes made? No. Some of these deaths were due to relatively simple issues like the trapeze hook getting tangled. There are several good alternatives to trap hooks on the market...but there is no requirement to use them (I use the Bethwaite Keyhole system myself).

Most teams accept the risk.



#54 DryArmour

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Posted 16 May 2013 - 01:12 AM

Basically MaugonNacra20 & Mark K have the multi-perspective right.
 
Wave piercing/low buoyancy bows work much better on small cats where crew weight is an effective/fast bow trim option.  Safe big cats need more buoyancy up front.
 
No-mans land is the better term.  Sail higher and you can head up in a puff, sail lower and you can fall off in a puff.  From a beam reach it's a long way in either direction to depower and probably ineffective & dangerous to try.  Better to trim out.  Since this is many cats fastest point of sail, it is to be enjoyed, not avoided.  Hull flying on a beam reach is all sail trimming.  A lateral capsize is the normal danger.
 
PItchpole danger usually occurs sailing downwind fast, gybing thru 90 degrees or less.  Falling off in puffs to depower.  As the wind increases, the gybe angle decreases, until there is nowhere to fall off to.  Sail loads exceed bow bouyancy and oops.  If you are only watching AWA and AWS, you can be in for a nasty surprise.  AWS is greatly diminished by boat speed.  Waves (or anything that slows your boat) are a common pitchpole factor.  Bury the bows into a wave back surfing deep, boat slows, inertia rotates the bows down, wind clocks aft and builds as AWS grows to TWS.  Heck of a way to find its really blowing 30+.  Way past time to have reduced sail.  Dumping the headsail early helps.  If you avoid the pitchpole and are releaved, you might miss that your boat is now rounding up (massive weather helm as only the main is drawing and no flow for rudders) into a lateral capsize.  Time to dump the main .
 
Any multi can be sailed downwind into a pitchpole at some wind strength and sea state.  In extreme conditions it is unavoidable under bare sticks.  Any multi can be sailed into a lateral capsize.  The crew keeps a multi safe. 
 
If Artemis broke first causing the crash, then it wasn't crew error.  Usually capsizes are crew error.
 
This accident does highlight why "capsizing" cannot be an acceptable part of large multi-racing.  What's fun on a beach cat doesn't scale up safely.

 

Excellent analysis and description Bill. Performance as you scale up comes at an exponentially greater safety risk. Falling from six meters on a beach cats is usually fun. Falling five stories from the back of AFTERBURNER could cause serious injury...falling 7+ stories and having a hard wing to avoid and a very large and stiff sprit obviously raises the danger level. Of course Oracle showed us all that it can be done with no resulting injuries but the dangers are obviously there.

 

I don't think without actually witnessing the Artemis event or  having  video any of us can really fully understand what happened. What I can tell based on almost 40 years of multihull experience, when the main beam folds often due to torsion and compression cycling, the rear beam often snaps just inside the hull/beam joint and that is exactly what appears to have happened based on the post crash video I have seen.

 

Low prismatic values forward seem crazy to me especially in a place where the ebb tides can cause really big,fat, square waves that could make tripping over the bows pretty easy to do.






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