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Old 30-07-2021, 06:02   #121
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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Originally Posted by noelex 77 View Post
Lets agree to disagree about the suitability or otherwise of brass seacocks.







A Google search indicates that Bavaria produced 25 Ocean 47 models. So if the development cost of certification is €4000 per boat. I disagree that is "no significant further cost", but the question remains do you feel this represents value for money?







Surely this is a bad, not a good feature of the standard. The standard does not even attempt to detect manufacturing mistakes such as the Lagoon with only 2mm thick fibreglass over the sail drive recently reported on CF. This is the link, post#403:



https://www.cruisersforum.com/forums...ml#post3454022









I disagree. The loss of the boat and the skipper's life was due to loss of the main windows and/or the forward hatch. It is also suggested that flexing of the fibreglass structure was a contributing factor.



The Class A standard certifies the suitability of the window and hatch design, as well as the strength of the fibreglass structure. No matter what your interpretation of the major cause of the sinking, these are all areas that are covered by the standard. Clearly in this case one or more of these items certified by the standard failed.


Of course nature will break anything , simply because it failed is not in itself a reason to query the underlying standard. One has to place the standard in the context it was designed to be applied.

The skipper lost his life due to different issues.
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Old 30-07-2021, 06:04   #122
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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Oh how wrong you are. I was in the Canary Islands a few years back when the ARC were getting ready to leave. Many, most, if not nearly all were new boat owners. A number had purchased their boat at the Southampton Boat Show, had it delivered to the Canaries and the first time they had set foot on-board was there. For one of these the wife's safety equipment was a healthy supply of Valium. But hey, the organisers check that your flares are in date, don't they? I have also had the misfortune to meet holders of so called fast track sailing qualifications who think they know it all because of the certificate.



The problem today is that sailors in small boats no longer believe they are taking risks, because the boat has a certificate and they have a certificate and the government will warn them about anything that could possibly do them harm. Like signs warning you not to go too near the edge of crumbling cliffs.


I did two ARCS , the vast majority were relatively experienced sailors.
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Old 30-07-2021, 06:08   #123
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

Quote:
Originally Posted by noelex 77 View Post
Lets agree to disagree about the suitability or otherwise of brass seacocks.







A Google search indicates that Bavaria produced 25 Ocean 47 models. So if the development cost of certification is €4000 per boat. I disagree that is "no significant further cost", but the question remains do you feel this represents value for money?







Surely this is a bad, not a good feature of the standard. The standard does not even attempt to detect manufacturing mistakes such as the Lagoon with only 2mm thick fibreglass over the sail drive recently reported on CF. This is the link, post#403:



....


I only mention seacocks because it’s fake news that the relevant ISO standard specifies brass , it clearly does not.

The RCD was and is not designed to monitor quality nor is there any onus to force the owner to remain “ in-class”

Should in be , maybe. It’s a very complicated process to instigate a continuous quality oversight system. Even iso9000 largely failed.

Ultimately is buyer beware on the end.
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Old 30-07-2021, 10:38   #124
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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They are not on the list of notified bodies so who will they use for the actual certification and is that extra?
They seem to be working as a subcontractor to IMCI:

From their service list:
Quote:
CE certification as IMCI Inspector
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Old 02-08-2021, 00:27   #125
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

This was an example of an experienced crew, on their own boat with a good brand reputation that they had sailed for many years in many different waters. They hit a storm stronger than what was forecast, and in the SE quadrant probably because they were trying to run for shelter to the Bay of Islands. The boat survived a number of knockdowns before the decisive damage. It hard to predict where an intense low will move and how fast it will move. Any boat in storm conditions will flex with that sea state, and there are plenty of videos of large commercial steel vessels flexing in bad seas to prove the point. I have personal experience of racing a 76foot aluminium maxi and watching the hull flex so badly it popped the forepeak hatch completely out frame and all, when coming off a wave into another short chop while beating into gale conditions on the Wild Coast on a Vasco Da Gama race and taking multiple tons of water below. I will never forget the sound of that water smashing up and down inside the alu hull. We tacked immediately and tried to tie sail covers over the forepeak frame reinserted but no go and turned and ran to protect the foredeck while we pumped her out. Race over. That hatch surround was strongly braced and probably stronger than the surrounding deck, but watching 76 foot of boat flex reminds you of how powerful water is in an excited state. There are conditions and rogue seas that can take you out no matter what kind of vessel you are in. These guys were unfortunate enough to encounter these conditions, and the boat and crew did well to survive multiple knockdowns. We learn from each such survival case, but questioning the ability of Kiwi sailors in waters off their own east coast is not being aware of how bad those conditions can get for any sailors in any vessel. Always easy to suggest other alternatives in comfortable hindsight, but the skip got his crew into the water in nightmare conditions having lost their liferaft, and they all made it bar him. So he did alright.
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Old 30-08-2021, 16:17   #126
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

My conclusion is that the window/s popped out and the fore-hatch opened due to hull deflections. Solution is design which allows for hull deflections in window installation, and hatch fasteners.


So if you venture far offshore in a modern production yacht it might be worthwhile looking at doing some mods to allow for deflections. Screw-on outside window covers are not going to help.
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Old 30-08-2021, 16:23   #127
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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Originally Posted by Kudu View Post
My conclusion is that the window/s popped out and the fore-hatch opened due to hull deflections. Solution is design which allows for hull deflections in window installation, and hatch fasteners.


So if you venture far offshore in a modern production yacht it might be worthwhile looking at doing some mods to allow for deflections. Screw-on outside window covers are not going to help.
I dont think any windows would have survived multiple knockdowns

the solution as identified in the report was to fit the strom boards, that were uselessly carried below

we can speculate as to why the hatch opened , I would contend shirt of hull destruction its unlikely it was opened due to deflection alone

The windows blew outwards exposively , again I suggest this was air pressure not deflection
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Old 30-08-2021, 16:44   #128
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

It was a window that caved according to report,
New recommendations for storm covers by NZ.
They had a drouge ready to deploy, but decided not to use the device.

https://boatingnz.co.nz/anatomy-of-a...-essence-pt-2/

https://www.maritimenz.govt.nz/comme...22July2021.pdf
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Old 30-08-2021, 17:01   #129
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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I dont think any windows would have survived multiple knockdowns

the solution as identified in the report was to fit the strom boards, that were uselessly carried below

we can speculate as to why the hatch opened , I would contend shirt of hull destruction its unlikely it was opened due to deflection alone

The windows blew outwards exposively , again I suggest this was air pressure not deflection

Sorry, but the air pressure theory does not hold up to even the most basic engineering analysis. Particularly if you are talking about a window designed to be hit occasionally by a wave.


Yes, fitting strong storm boards in place of a lost window would be helpful, but as a plan B, not a starting point.
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Old 30-08-2021, 17:27   #130
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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Sorry, but the air pressure theory does not hold up to even the most basic engineering analysis. Particularly if you are talking about a window designed to be hit occasionally by a wave.


Yes, fitting strong storm boards in place of a lost window would be helpful, but as a plan B, not a starting point.

err storm boards are useless after the windows failed, the boat filled alomost instantly

I fail to see why air pressure as a result of a large ingress of water through the open hatch wouldn't have generated considerable pressure on the windows , which are not designed to withstand outwards pressure that much
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Old 30-08-2021, 18:55   #131
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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err storm boards are useless after the windows failed, the boat filled alomost instantly

I fail to see why air pressure as a result of a large ingress of water through the open hatch wouldn't have generated considerable pressure on the windows , which are not designed to withstand outwards pressure that much

Assuming the inside of the boat instantly filled up 20% of its volume, with no air leakage out, you are talking about an increase in air pressure of around 3 psi. Not much, and that would be the max.
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Old 31-08-2021, 02:31   #132
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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Assuming the inside of the boat instantly filled up 20% of its volume, with no air leakage out, you are talking about an increase in air pressure of around 3 psi. Not much, and that would be the max.
The report says"The cabin windows on Essence were approximately double the size specified under the Regulations ". The regs specify 1852 sq cms. Assuming this means one window, not the total of all windows that is 1852 x 2 = 3704 sq cms which equals 574 sq ins (thanks Google) which at 3 psi is 570 lbs. At 180 lbs each that's more than three men jumping on the window.

If it was plastic then it would be sure to bend reducing the lip size. Not knowing the exact construction of the window and its edge I would hesitate to put this as a definite thesis but its far from impossible.

570 sq ins does sound like a big window...............
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Old 31-08-2021, 02:51   #133
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

am I the only one that sees these windows and doesn't really think they look dangerously big?
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Old 31-08-2021, 02:59   #134
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

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The report says"The cabin windows on Essence were approximately double the size specified under the Regulations ". The regs specify 1852 sq cms. Assuming this means one window, not the total of all windows that is 1852 x 2 = 3704 sq cms which equals 574 sq ins (thanks Google) which at 3 psi is 570 lbs. At 180 lbs each that's more than three men jumping on the window.

If it was plastic then it would be sure to bend reducing the lip size. Not knowing the exact construction of the window and its edge I would hesitate to put this as a definite thesis but its far from impossible.

570 sq ins does sound like a big window...............
might sound that way to you, but we have 10 windows that are bigger than this...plus double bi-fold doors to the cockpit

but then we don't have 5-10mt of lead swinging off the bottom of the boat...

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Old 31-08-2021, 16:05   #135
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Re: Maritime NZ report into the loss of the yacht Essence, October 2019

Quote:
Originally Posted by Kudu
Assuming the inside of the boat instantly filled up 20% of its volume, with no air leakage out, you are talking about an increase in air pressure of around 3 psi. Not much, and that would be the max.
The above assumption is pretty hard to imagine happening. The ingress would not be instantaneous and there would be leakage out as it entered, both at the hatch and from all the other non-air tight spots in the boat. Hence, the 3 psi figure, IMO, would not even be approached let alone reached.

I think some other mechanism was responsible for the failure.

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