Maritime NZ report into the loss of the yacht Essence, October 2019

[boatman61]

Having had a wave dump on my Hunter 37 which punched out the fwd bulkhead and broke the tabbing on one side of the main bulkhead I can easily see something like that dumping on the boat being enough to pop the windows.. the down pressure is huge.

[Ericson38]

Originally Posted by NevilleCat

am I the only one that sees these windows and doesn't really think they look dangerously big?

I think they look big, compared to ours.

[qwert]

Originally Posted by boatman61

Having had a wave dump on my Hunter 37 which punched out the fwd bulkhead and broke the tabbing on one side of the main bulkhead I can easily see something like that dumping on the boat being enough to pop the windows.. the down pressure is huge.

The down pressure is indeed huge. A static 28 inch high column of water exerts one pound per square inch then you can add the velocity at which the water is moving and you have a considerable force

[wingssail]

Originally Posted by NevilleCat

am I the only one that sees these windows and doesn't really think they look dangerously big?

I don't think they look dangerously big, there are boats with bigger windows.

[boatman61]

Originally Posted by wingssail

I don't think they look dangerously big, there are boats with bigger windows.

Let's sail them down to NZ and put them in the same situation and see what happens..
Builder or Nature..

[Mr B]

A single wave crashing down on a deck of a ship takes out the steel hatch covers on bulk freighters,
A single wave is not a bucket of water thrown at the windows,

A single wave will be many Tons in weight and the volume of that same wave is Massively huge,
A single wave coming over the transom could easily fill a boat full of water if the rear door or hatch is open to allow ingress,

The Tasman Sea, The Western Pacific Ocean, Are not Millponds when the weather decides to turn its angry button on,

A 20 foot wave or above crashing inside any boat thru an open door, has a very good chance of popping windows out,

The Force of water in Bulk volumes has a very destructive power behind it,
The Spirit of Tasmania Ferry had its windows smashed in on the tenth floor a few years back in Bass Strait,

[250224]

Originally Posted by Kudu

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.

Why aren't they going to help?

And/or what are these covers exactly? I would have thought that these are covers which overlap th windows a little bit and are screwed into (how do you say that) four threads in the hull besides the window.

[wingssail]

Originally Posted by boatman61

Let's sail them down to NZ and put them in the same situation and see what happens..
Builder or Nature..

I happen to agree, particularly the Moody (left), However the Elliot (right) is a New Zealand boat, built in the early 2000's and well travelled, and seems to have survived.

That being said, I do not have any windows on my boat.

[Cloroxbottle]

Originally Posted by goboatingnow

The issue of the loud “ booming noise “ would suggest air pressure was the issue ie explosive decompression .

I find it a little hard to believe that the hull of the vessel would be compressed to the point it would reduce the interior volume to the extent necessary to "pressurize" the inside hull in the way an airliner cabin is pressurized resulting in an explosive decompression...? At least without causing a catastrophic failure of something else like the deck/hull joint?

Perhaps it was something more like this description of traumatic brain injury: "In head injury, a coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was hit." The side that contacted the ocean surface after the knockdown saw forces transmitted along the hull or bulkheads resulting in the failure of the sealant and windows blowing out on the other side?

[mglonnro]

Originally Posted by Jim Cate

Seems that they might have been wrong. Question is why they felt so confident? Was it due to the "A" rating, or some other factor? We will never know...

The rating was from 1999, under the old rating system? Or did they have it recertified later? In the accident report, they quote the original manual, so I guess it is the older one.

The latest approved ISO standards behind the ratings seem to be from the 2010s so I assume there might be some updates there, as well, regarding hull windows. (But I don't know.)

Anyway, the RCD 2013 general guidance statement says:

A recreational craft given design category A is considered to be designed for winds that may exceed wind force 8 (Beaufort scale) and significant wave height of 4 m and above but excluding abnormal conditions, such as storm, violent storm, hurricane, tornado and extreme sea conditions or rogue waves.

Given the 60 knots (or above) wind at the time of the final knockdown, it seems that the conditions were at the limits or above the current RCD specifications.

[Paul L]

First hand account of the loss of Essence and the rescue of the crew. Harrowing account.
https://www.yachtingmonthly.com/sail...Q0l47vq2S20zHM

Interesting comment in the lessons learned section:

Storm shutters or battens: Fit them when bad weather is forecast – waiting until the storm is raging is too late. Battens reduce the likelihood of the windows being burst by the distorting forces exerted on the roof and hull during a knockdown or roll-over. Shutters can significantly reduce water ingress if any windows are burst. This could make the difference between the boat sinking and making it home.

[Buzzman]

Sobering, how quickly they went from sailing along, to total wreck, then sunk and afloat on the sea....
Bolted on windows would probably have helped as well.
No bilge pump could have pumped it out as fast as it was clearly coming in, but with storm boards....maybe a good pump - or two - might have made the difference.
I also question why they were sailing, and had not thrown a drogue overboard.
Wonder if he discusses this in the book?

[KJThomas]

Originally Posted by JPA Cate

I agree with this completely. However, New Zealand is not a very populous area, a small nation, and they are responsible for rescues at sea for their surrounding oceans till they get to the border with Australia, who also have a lot of sea miles in their jurisdiction. And they will tell you their overkill ways are best for sailors. We may beg to differ, but they are unlikely to change.

Ann, aboard in Australia

Cat 1 requirements, for New Zealand are pretty much what any sensible Skipper would do. It seems a bit weird and arrogant, objecting to doing what any competent and experienced skipper should be doing.
Unfortunately not everyone is sensible, which is why we need rules.

I know several of the experienced ocean sailors and yacht inspectors involved. They are not prone to "overkill" or wanting equipment that is not necessary.

MNZ do consult with and take advice from experienced cruisers.

In NZ input is invited to any changes in rules, so if any of you thinks it should be improved, put in a submission to maritime NZ.

[fxykty]

Originally Posted by Buzzman

Sobering, how quickly they went from sailing along, to total wreck, then sunk and afloat on the sea....
Bolted on windows would probably have helped as well.
No bilge pump could have pumped it out as fast as it was clearly coming in, but with storm boards....maybe a good pump - or two - might have made the difference.
I also question why they were sailing, and had not thrown a drogue overboard.
Wonder if he discusses this in the book?

We’ve got the book. In chapter 1 it discusses in detail the voyage and the last day leading up to the final knock down and roll. Conditions had built quickly from 35 knots overnight to gusting 60 knots by mid day, with relatively short and steep swells to match. They had a triple reefed main and storm staysail, sailing a broad reach.

The book goes into detail in Chapter 7 about the author’s analysis of the sinking. Certainly 35 knots from astern is no big deal and it seems they simply adapted to the conditions as they worsened during the day. They were hand steering as the autopilot could not cope. The wave that sank them was not noticeably larger, louder, or steeper than the regular waves, until the moment he found himself airborn in the cockpit during the final knockdown.

Regarding a drogue, the author doesn’t mention that as an option, nor a sea anchor. Whether either was on board is not mentioned, but the author writes that he believes they were handling the conditions well enough. He notes that the conditions were bad but not the worst that he had experienced in 14 previous trips from Fiji to New Zealand.

Even if they had had a drogue, I expect that when you’re that close to safe harbour (they sank 25 miles out from the entrance to the Bay of Islands) the inertia of wanting to get there would have out weighed launching the drogue. In addition, the forecast was for the strong winds to quickly swing to offshore, making landfall even more difficult.

[goboatingnow]

Anyone who has used a drogue will know they are not a 100% solution , nor will they solve the issue of a breaking sea.

I’ve not read the book but has it explained the open forward hatch issue. !

Nor do I believe storms would have saved this yacht if the windows forces came from inside