NTSB report on DAWN incident

The NTSB report on the DAWN's 'rogue wave' incident can be found at

http://www.ntsb.gov/publictn/M_Acc.htm

The NTSB report on the DAWN's 'rogue wave' incident can be found at

 

http://www.ntsb.gov/publictn/M_Acc.htm

Thank you I will read it all but as often happens here I jumped to the conclusion.

Probable Cause

The National Transportation Safety Board determines that the probable cause of the damage to the Norwegian Dawn and of the injuries suffered by its passengers was waves breaking over the bow during the ship’s unavoidable encounter with severe weather and heavy seas.

Racing back ?

After attempting to minimize the ship's exposure to the forecast conditions, the master changed his itinerary and slowed the vessel. Rather than attempting to maintain the scheduled arrival time in New York, the master decided to lower the ship's speed and change its heading for the passengers' comfort.

The ship's operating at reduced speed when the waves hit probably limited the damage.

From what I read from this detailed report, the Captain could not have handled the unavoidable situation any better than he did. The fact that he remained on the bridge throughout the night confirms in my mind that he recognized the potential of the conditions he might face. Well done!

What does pitch and roll mean?

ts01854

In simplistic terms:

Pitch - fore and aft motion (think of teeter-totter, with midships being fulcrum).

Roll - side to side motion (think of metronome).

Now let's hold our breath until the news media gives this report the same attention they gave the incident. LOL

I sat back b4 commenting once I found this.

I note the lack of any reference to a rogue or giant wave.

"The master, who had been on the bridge throughout the night, told investigators that he felt the ship pitch three times in succession. The watch officer stated that all the waves were very large, and that all were roughly the same height. On the third wave, he said, the ship’s bow took heavy green seas"

EXACTLY! And brings to bear the poster's question about pitch and roll. What happened here is the ship's pitchng fell into harmony with the period of the swells. The bow is going up and down due to the force of the swells, and at the same time the swells keep coming. In the series of swells described the ship got to a point where the bow was driving down due to the pitch as it impacted the next swell trying to force it up. MAJOR FORCES interacting here. The bow drives down into the swell that is trying to push it up. The flare of the bow plows the water aside and it explodes up as the ship continues forward. Have this happen too big and too hard and that water can come crashing over the bow and onto the superstructure....or 'green water over the bow.

Since the period of the waves is never constant, dealing with this is called seamanship. Which is NOT saying the Master did anything wrong. One must be nearly constantly altering speed and course to avoid this situation...and it still happens. Add the factor of passanger (non-sailor) comfort and you see why the Master earns his pay while being on the bridge 'all night'. Slow speed and steering into the swells is a proper action IMHO - but you can't go too slow either. It is a balance with the factors constantly changing. If things still get pounded then you come about, also a tricky maneuver in heavy seas, and run down swell. Although a following sea can be a nasty ride too.

I'll have to see if I can post some of my video of this exact situation from a trip in the Bearing.... a real E-Ticket ride as they used to say :D

Capt BJ

Our one trip across the Bering Straits, on the old Sky Princess, 4-97, was smooth, but very cold. They had to close the outside decks due to ice build-up.

A trip in the China Sea, 11-86, on the little Golden Odyssey, a 10,000GRT liner, was very rough, trying to outrun the back end of a typhoon. We had green water over the bridge, screws out of the water, and inclinometer pegged several times. YIKES!

Travel across the seas can be an adventure.

Thanks for the lesson, I undertand now

I wouldn't be so sure that NCL is absolved of negligence with this rogue wave business. I heard the captain's wife was wearing capris in the dining room that night. Coincidence?

The NTSB determined that the probable cause of the damage to the Norwegian Dawn was, "waves breaking over the bow ...". Who would have guessed? I guess my theory that it was caused by a sea monster was wrong.

So it looked like this

http://members.dsli.com/schooner/triumph/Triumph1.JPG

So it looked like this

 

http://members.dsli.com/schooner/triumph/Triumph1.JPG

Yes, except you are using the wrong ship from the wrong line going in the wrong direction in a different ocean. But other wise it looks right. :)

There was an in depth article in the Phil Inquirer that ran for 3 days.

The Gulf Stream and the Jet stream meeting causes the worse storms in any ocean in the world, especially in winter. This phenomenon is only just being studied extensively.

It was very, very interesting. Don`t know if it is available on the net.

BTW the storms, called Nor`Easters are going to be getting worse and more intense due to the changes in the water temp (and other things).

There was an in depth article in the Phil Inquirer that ran for 3 days.

 

Majestic, mysterious, monstrous

from

http://nl.newsbank.com/nl-search/we/Archives?p_action=doc&p_docid=10EA8A31F174FED8&p_docnum=1

So it looked like this

 

http://members.dsli.com/schooner/triumph/Triumph1.JPG

WOW! That picture is very scary. I hope no one was in front of the ship when that happened and I certainly hope that doesn't happen when I'm on the Spirit in April.

WOW! That picture is very scary. I hope no one was in front of the ship when that happened and I certainly hope that doesn't happen when I'm on the Spirit in April.

Picture is a known fake....:D

So, what's the latest on the action being taken for those passengers on the actual sailing?

Anyone still around?

One more point notice that this was the third wave in a series. For some reason waves tend to come in threes. So when the ship starts pitching on the first, the second increases the pitch and the third(from the prespective of someone on the ship) would seem considerably larger and wham you get the damage that occurred. Be glad the ship wasn't turned sideways or you would have gotten the SS Poseiden...I've seen those pictures too and I'll bet someone thinks they are phony...they are real I saw it on TV...

smeyer is correct - waves tend to come in threes (often described as 'sister" waves). We had a tragic situation near my cottage on Lake Huron several years ago where "sister" waves struck and sank a small tour boat and two children died. Never underestimate the power of wave action on large bodies of water.

here's a frame capture from some video I'm trying to post....

shows the bow blowing into a swell - speed was 5 knots - swells running about 20 feet. This was the third in a set, where we'd rode over the first two smoothly

That's actually a pretty small one - a controlled situation. When that water comes up and over is when things get exciting!

We rode like this for about 4 days one winter in the Bearing...wind was about 45 knots most of the time. Fortunately the temps were up a bit but no icing.

Here is a similar shot from the Dawn webcam.

Here is a link to a series of pictures of CCL ship in Rita that shows the effects of pitch.

http://community.webshots.com/album/463051526fxtCvC

Here is a link to a series of pictures of CCL ship in Rita that shows the effects of pitch.QUOTE]

 

May be a naive question, but do you know who took these pics?

Thanks, SailAways

 

Happy Holidays

SMeyer mentions Poseidon. While capsizing is a fairly remote possibility, Halsey's Fleet did lose three destroyers to capsizing during a typhoon in the China Sea. Those old "tin cans" did have a fairly high center of gravity, what with all the equipment (guns/radar, etc) added topside during the course of the war.

We were on the old Oriana sailing North from Acapulco, Dec 70, during a heavy storm. Because of the frequency of wave action, the Captain turned the ship, which reduced pitching almost immediately, but we did have an interesting "up and down" ride, not unlike a rapid elevator. It was easier to just sit down than trying to walk, as the deck would just drop out from beneath your feet.

We're scheduled to go 'round the Horn next March on Regal Princess, and we are hoping that the Cape lives up to its rough reputation.