Cruisers Forum
 


Join CruisersForum Today

Closed Thread
 
Thread Tools Rate Thread Display Modes
Old 13-06-2008, 15:36   #61
Senior Cruiser
 
Therapy's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: W Florida
Boat: The Jon boat still, plus a 2007 SeaCat.
Posts: 6,894
Images: 4
Quote:
Originally Posted by Alan Wheeler View Post
Factor, Quite a pointless question. That is like saying, how many people have died in car accidents, between cars that are white and cars that have purple pokadots on them. There maybe a larger number of multi guy's on this multiforum, but it does not mirror the number of monos vs multis. Multis are still very much a minority out there and especially if you go back 18yrs.
And........

I don't think it is a pointless question.
It may be irritating but if the data could be collected then a simple division would give a apples to apples number.
Then we could discuss how they came to be in that predicament and we could speculate as to their seamanship or.......................etc.

I should take my medicine...........wait, I did............maybe I should take less...........errrr...............
__________________

__________________
Therapy is offline  
Old 13-06-2008, 15:38   #62
Senior Cruiser
 
sneuman's Avatar

Cruisers Forum Supporter

Join Date: May 2003
Location: Jamaica
Boat: Tayana 37 Cutter
Posts: 3,167
Images: 37
Quote:
Originally Posted by Southern Star View Post

In any event, while I am sorry to burst your bubble, monohulls do capsize! Some, like the Smeeton's offshore boat Tzu Hang (going from memory here on the name), can actually capsize twice in successive voyages (albeit after installing a new rig and new house before the second one, due to the damage inflicted by the first).
As long as we're endeavoring to be accurate here, at least one of the Smeeton's mishaps was a pitchpole not capsize. Can't remember on the other.

Also, lots of cruisers have a better AVS than 135 degrees.
__________________

__________________
Voyage of Symbiosis: http://svsymbiosis.blogspot.com/
sneuman is offline  
Old 13-06-2008, 16:18   #63
Registered User

Join Date: Sep 2007
Location: Colombo
Posts: 1,059
Quote:
Originally Posted by Southern Star View Post
Midland One - the truth in the statement that cats are less likely to capsize is monohulls has nothing to do with the number of them sailing (if you re-read it, you will see I referred to likelihood of capsize, not the total number). The truth in that is because of form stability. If one looks at stability curves, conditions that will cause a capsize in a monohull will leave a cat upright.
I have already posted on initial stability. I think you will find that the relationship of initial stability to the propensity to capsize is pretty tenuous (some could say that initial stability is all cats have as there is no ballast but I am using it here in the sense inferred by your post that maximum stability is high at a low angle of heel as for a cat). Stability curves are static curves not dynamic - if one considers that the conditions that cause capsizes are "static" and not "dynamic" then so be it.

I would, however, suggest, that is not the case - two very simple examples. 1. Static curves for a cat take no account whatsoever of the hull and bridgedeck windage when the windward hull leaves the water (so presumably if initial stability is of great importance for preventing the ultimate event cats only capsize in low wind conditions). 2. Static curves for a mono take no account of the work required to roll the vessel against its transverse mass moment of inertia (it is so that the area under the stability curves is proportional to the energy required to heel the boat in calm conditions but says nothing about the work required ie how fast the energy is to be expended). Lots of other matters related to sea state, wind, effect of rig on monos once it is submerged both in capsizing beyond mast on water and with respect to the recovery roll, keel damping, heel on face of waves, loss of stability from sagging or hogging, etc, etc.

Considering that initial stability is the important matter that makes one vessel less resistant to the ultimate event is, in my view, foolhardy in the extreme.[/quote]


[quote=Southern Star;171659]Further, there are now many cats designed with standing rigging that breaks before the boat reaches a level of pressure that would cause a wind-induced capsize.[\quote]

Sounds like fun . I find the need to reduce the safety factor in the rig to zero, presumably under the lower wind loads when heeled, so that it fails as a "safety" precaution an intriguing concept .
__________________
MidLandOne is offline  
Old 13-06-2008, 16:24   #64
Registered User

Join Date: Dec 2007
Posts: 340
Confusion??

There seems to be a misconception out there that extraordinary conditions are required to capsize a cruising catamaran. Not so. Below are a couple of calculations obtained from James Wharram Designs -Home of the self-build Catamaran. showing only very moderate conditions and no wave action required. Basically a moments inattention whilst maybe making a cuppa can lead to a swim. If one adds the size of the spinnaker into the equation a glitch with the autopilot can lead to a swim in much lighter conditions.

Farrier refers to his tris as cruisers ,and one recently was blown over in moderate conditions whilst passage making, as discussed in another thread here.

A mono will surely only be knocked down a little, at worst ,in these conditions.
Figure 6

Factor, as for the catamaran capsize I refered to in an earlier post, the information was read in a copy of Australian multihulls as I explained. Unfortunately I no longer have my mag collection so you'll have to thumb through yours.
__________________
cat skin hat
catty is offline  
Old 13-06-2008, 19:49   #65
Registered User

Join Date: Jun 2008
Boat: Designing a global explorer (full keel & steel)
Posts: 353
blue water & Rose Noelle

Quote:
Originally Posted by Factor View Post
I insured a previous cat
G'day,

Am curious, does your insurance cover blue water? I consider “blue water” to imply rounding of both Cape's (Hope & Horn) during all year round.

Quote:
Originally Posted by Factor View Post
BTW got any further info on the capsize at airlie of the 40 foot cat you mentioned, I would be keen to add it to my data base.


Not responding for the member but asking if you've ever heard of the Rose Noelle? The capsized trimaran of NZ in 1989, adrift for 119 days.
__________________
exfishnz is offline  
Old 13-06-2008, 19:50   #66
Marine Service Provider
 
Factor's Avatar

Join Date: Dec 2006
Location: Brisbane Australia
Boat: Corsair Dash MKII
Posts: 4,082
Hi Catty - had a look through them all this morning - cant find it, Went back to about edition 35 which is mid late nineties.
__________________
Factor is offline  
Old 13-06-2008, 19:51   #67
Marine Service Provider
 
Factor's Avatar

Join Date: Dec 2006
Location: Brisbane Australia
Boat: Corsair Dash MKII
Posts: 4,082
Quote:
Originally Posted by exfishnz View Post
Not responding for the member but asking if you've ever heard of the Rose Noelle? The capsized trimaran of NZ in 1989, adrift for 119 days.
Yep - great example of how a capsized multi can be its own life raft.
__________________
Factor is offline  
Old 13-06-2008, 19:58   #68
Registered User

Join Date: Jun 2008
Boat: Designing a global explorer (full keel & steel)
Posts: 353
45 south

Quote:
Originally Posted by cooper View Post
By virtue of the design the above is not possible in a cat.
G'day,

Very good points.

Have spent time below 45 south and experienced what happens when rouge waves break across a vessel.

As light, quick, beamy & roomy multi's may be, I think I'll take a pass on them & stick with water tight, strengthen & full keel mono's. I may roll a 360, but I can plan & act for it.

One can't do much* with a capsized multi when there's wave after wave continually breaking.

* except make peace with their maker.
__________________
exfishnz is offline  
Old 13-06-2008, 20:08   #69
Registered User

Join Date: Jun 2008
Boat: Designing a global explorer (full keel & steel)
Posts: 353
Quote:
Originally Posted by Factor View Post
Yep - great example of how a capsized multi can be its own life raft.
Sorry mate, I disagree. It is only an example of pure luck after a capsize. Had the current never taken them back to land, they'd be dead. Had they experienced another storm they'd be dead.

I watched a documentary of it in NZ, interesting how they couldn't get their flares from the mess in the half submerged hull, yet ships passed them by from a distance.
__________________
exfishnz is offline  
Old 13-06-2008, 21:19   #70
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,452
Images: 69
Quote:
Originally Posted by exfishnz View Post
G'day,

Very good points.

Have spent time below 45 south and experienced what happens when rouge waves break across a vessel.

As light, quick, beamy & roomy multi's may be, I think I'll take a pass on them & stick with water tight, strengthen & full keel mono's. I may roll a 360, but I can plan & act for it.

One can't do much* with a capsized multi when there's wave after wave continually breaking.

* except make peace with their maker.


The point that can and should be learned from the Rose Noelle is that if some preperations are made in advance, a capsized multihull can be very survivable. For instance, if they had their flares in a watertight container, easily acessible, they might have been rescued much sooner. These days, with EPIRBS and better communications, nobody should ever have to drift for months on end waiting for rescue.

Just as you would plan and act for the 360' roll that might happen to your mono, a multihull crew can plan and act for a possible capsize.

There wouldn't be much you could do with a dismasted and disabled mono either in a situation where conditions were severe enough to roll you. Except prepare to be rolled again. And again. If you read the accounts of the Queens Birthday storm you will see that several monohulls were rolled repeatedly.
__________________
44'cruisingcat is offline  
Old 13-06-2008, 21:22   #71
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,452
Images: 69
Quote:
Originally Posted by catty View Post
There seems to be a misconception out there that extraordinary conditions are required to capsize a cruising catamaran. Not so. Below are a couple of calculations obtained from James Wharram Designs -Home of the self-build Catamaran. showing only very moderate conditions and no wave action required. Basically a moments inattention whilst maybe making a cuppa can lead to a swim. If one adds the size of the spinnaker into the equation a glitch with the autopilot can lead to a swim in much lighter conditions.

Farrier refers to his tris as cruisers ,and one recently was blown over in moderate conditions whilst passage making, as discussed in another thread here.

A mono will surely only be knocked down a little, at worst ,in these conditions.
Figure 6


Factor, as for the catamaran capsize I refered to in an earlier post, the information was read in a copy of Australian multihulls as I explained. Unfortunately I no longer have my mag collection so you'll have to thumb through yours.
This is almost too stupid to be worth responding to. Do you really think there are CRUISING boats that will capsize in 13.6 knots of wind? Seriously?
__________________
44'cruisingcat is offline  
Old 13-06-2008, 22:35   #72
Registered User

Join Date: Sep 2007
Location: Colombo
Posts: 1,059
Quote:
Originally Posted by 44'cruisingcat View Post
This is almost too stupid to be worth responding to. Do you really think there are CRUISING boats that will capsize in 13.6 knots of wind? Seriously?
I suggest that you read the link that Catty provided before you start calling people here and James Wharram "stupid". You clearly do not understand what is being said .
__________________
MidLandOne is offline  
Old 13-06-2008, 22:51   #73
Registered User

Join Date: Jan 2007
Location: Fremantle Australia
Boat: Schioning 12.3 "Wilderness" Bi-Rig under construction
Posts: 558
Send a message via Skype™ to Whimsical
Reading the result without looking at all the data doesn't make sense either.
cat A has a a very narrow beam and cat b has an enormous amount of sail in relation to its wieght.
My cat is lightwieght with a largish sail area but the numbers come up at a lot more than these two examples.

Getting back on topic.
I agree there is a huge difference between a knockdown and a capsize but I get the impression people think that a mono knocked down is of little consequence. I would think that if one wasn't prepared for and aware of the impending situation having the world turn 90 degrees could be quite painfull.

Mike
__________________
Whimsical is offline  
Old 13-06-2008, 22:52   #74
Registered User

Join Date: Jun 2008
Boat: Designing a global explorer (full keel & steel)
Posts: 353
Quote:
Originally Posted by 44'cruisingcat View Post
...instance, if they had their flares in a watertight container... with EPIRBS and better communications, nobody should ever have to drift for months on end waiting for rescue.
Agreed. Epirb was available in 1989 (we had 'em), don't know if they carried one. I've also fished the east coast (by Napier where they rolled), but don't know how big the wave was that rolled them.

Quote:
There wouldn't be much you could do with a dismasted
Fair point.

Perhaps my previous post was not clear enough (my apologies), I should have stated that you can design rather than just plan with a standard production yacht. Am researching rigging for a custom vessel that can handle such capsize when rounding the Horn during the Antarctic winter (don't plan winter crossing but that's the conditions the vessel must meet). Previous discussions with designers suggest perhaps a schooner with heavier rigging (doubling up with galvanized wire) & mast height 1/3 less than that of a comparable sloop/cutter.

Quote:
and disabled mono either in a situation where conditions were severe enough to roll you.
If we're talking production yachts then I agree that one's options are limited. If we're talking custom design then that's different. One can fire up the engine so long as the prop is clear of any galvanized wire & sails. Any loose ropes around the prop can be tied off to a heavy cleat & cut free using an installed rope cutter on the shaft.

Having said all that, everything (engine, box, fuel tanks etc) must be designed to take the stress loads of all the rolling.

Quote:
Except prepare to be rolled again. And again.
Sure.

I would prefer the design & strength of being rolled again & again (eg: solas enclosed life boat with engine) rather than only being rolled once & risk being broken up to pieces.
__________________
exfishnz is offline  
Old 13-06-2008, 23:43   #75
Registered User

Join Date: Mar 2007
Posts: 232
Quote:
Sailorman, your blanket statement that 'monohulls are safer than multihulls...' really doesn't advance any discussion.
Well...you are posting in response to it aren't you ?
Quote:
That may be your opinion, but it is certainly not a truisim or statement of inarguable fact.
Now here we could banter back and forth forever. The subject that we are discussing has so many possible permutations and differentiating factors that there is probably no absolute determination possible in the matter. Hence, we are forced to rely on our own opinions, which we formulate over the years based on things we absorb and things we experience. At some point in our lives, these opinions become the "facts" upon which we organise our lives. In a nutshell - you can't prove that my opinion is NOT a fact any more than I can prove that it is.

So we have to move ahead based on that, accepting of our own biases as well as those we find in others. From my perspective, based on things I have seen, heard, and sailed on, monohulls are safer boats than multihulls.

Not a fact - just an opinion.

I think that anyone reading these pages understands that there are several opinions held on just about everything. Questions and comments are posted in order to elicit varying opinions. If it weren't so, there would be no need for any more than one response to a comment.

Quote:
Various insurance companies, who make their living on these issues, disagree. And quite apart from the total loss of the vessel (which must also include in the analysis the fact that most multis are able to sail safely in depths that could tear the bottom out of most monos), you must also consider the fact that the lack of heeling leads to a safer environment for sailing, meal preparation, maintenance etc.
This is your opinion, and as you mention, the opinion of some insurance firms. I believe your opinion is certainly as valid as mine, but the insurance firms tend to base their assumptions on regionalised actuarial tables, which rely on adverse events for their modelling. As there are far more monohulls in the world than there are multihulls, their tables are suspect in my opinion.

I think you might prefer sailing multihulls to monohulls, therefore, you are able to enumerate their better points. I prefer monohulls to multihulls.

While the lack of heel on a multihull may make the boat somewhat easier to move around on in some sea conditions, to my mind, the stresses imposed on the hulls, rig and crossbeams as the boat fights its own buoyancy in the process of remaining relatively level, is less desirable over the long term than having to use a handhold on occasion.

This is just one of many issues I could raise to illustrate the basis of my opinions. To actually discuss all of them at length would be an exercise in futility, and would not likely raise anything new, as the subject has been beaten to death here and on just about every other forum. So we'll just have to agree to disagree.

Quote:
Obviously, some monos are safer than some multis in some conditions; just as obviously, some multis are safer than some monos in some conditions.
I will allow that when sailing through shallow waters without a chart, it would be easier to avoid grounding in a multihull. So in that case I believe that yes, the multihull would be "safer". But, and it's a very subjective "but", I don't sail in that environment.

Here, the water is deep and my concerns have more to do with the weather than the submerged terrain. So while shallow water may be a major concern for you, returning from beyond the AVS is a much more important one for me.

As I mentioned earlier, the things that I have come to accept as fact are merely perceptions based on repetitive affirmation. As are the "facts" that you live with.

To sum up: while I am indeed flattered that the opinions I typed seem so authoritative as to be taken for fact, they are ultimately only opinion and no more can be read into them than that. The same must be said about any comments that might contradict MY opinions

Happy sailing !
__________________

__________________
Sailormann is offline  
Closed Thread

Tags
capsize

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Capsize Ratio Scott k General Sailing Forum 30 14-03-2013 07:05
Monohulls can do it too! 44'cruisingcat Multihull Sailboats 13 21-04-2008 06:19
OUTREMER CAPSIZE eskfreedom Multihull Sailboats 39 19-02-2008 12:34
Is there a "Consumer Reports" for monohulls? coyotewrw Monohull Sailboats 10 02-03-2007 14:04
Capsize ratio lancercr Monohull Sailboats 37 08-02-2007 07:42



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:27.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.