In the previous post there is a video of the track.

When Crystal turns around to come back to the collision point it does this:

2:03:32 local
65 deg 12.1 kn

to

2:06:07
335 deg 7.6 kn

it keeps turning, but just that data shows it took 2 minutes 35 sec to turn 90 deg

speed at collision was 18 kn

quote:

Originally posted by sdy:
In the previous post there is a video of the track.

When Crystal turns around to come back to the collision point it does this:

2:03:32 local
65 deg 12.1 kn

to

2:06:07
335 deg 7.6 kn

it keeps turning, but just that data shows it took 2 minutes 35 sec to turn 90 deg

speed at collision was 18 kn

But at what rudder? Standard? Full? Hard?

Standard rudder is something like 15-20 degrees. Full is probably 30 or so. Hard is as far as it will go.

Speed has a role in how fast you turn, too.

quote:

Originally posted by JALLEN:

quote:

Originally posted by sdy:

quote:

The container ship steered hard to starboard (right) to avoid the warship, but hit the Fitzgerald 10 minutes later at 1:30 a.m., according to a copy of Captain Ronald Advincula's report to Japanese ship owner Dainichi Investment Corporation that was seen by Reuters

The data from Crystal and the data from DDG 62 should be able to definitively prove or disprove that statement.

The Marine Traffic data has Crystal at 68 deg from 115 am to 127 am. The statement above says Crystal did a hard right at 120.

The fact that Marine Traffic has Crystal course at 112 deg at 130am, would support a hard right turn just before the collision.

Yep, that doesn't make a lick of sense.

I fully realize the speeds and distances it takes to maneuver these large ships, but hard right ten minutes before colliding?

It also likely means a crossing situation rather then overtaking.

A freighter captain told me it takes 9 miles to stop a freighter under a normal stop. 6 miles in an emergency stop and you break $250k worth of stuff.

I also think it takes a while to make a decent turn when at cruise speed.

Quite honestly, I think the freighter captains story is bs, about using lights to signal them. Your first course of action would be to call them on the vhf radio. But, impossible to prove or disprove using lights.

Whistle signals generally are not used at distances over a .5-1 mile as they generally won't be heard inside a wheelhouse over other noise. Usually they're used in harbors and such.

quote:

On the Navy bridges I have been on, there are two sailors "at the controls" a helmsman at the wheel and a lee helmsman on the engine order telegraph,

On modern "tin cans" such as gas turbine FFGs and DDGs the helmsman and lee helmsman are one and the same (meaning only one sailor performing both watches). Everything else rings true from my time aboard surface ships albeit decades ago.

So without having to read the entire thread, is there any consensus yet on exactly what happened? I'm struggling mightily with how this could have happened given the agility of the Fitzgerald and what I would like to believe is the expertise and training of her crew.

Lead in the Naval Investigation ...

Rear Admiral Brian P. Fort
Commander, Navy Region Hawaii/Commander, Naval Surface Group Middle Pacific



BIO: http://www.navy.mil/navydata/b...avybio.asp?bioID=991

Source: http://gcaptain.com/former-ddg...itzgerald-collision/

Read more: https://news.usni.org/2017/06/...lision-investigation

So if the freighter saw the destroyer, tried to signal the destroyer, then struck the destroyer, why did they wait so long before turning around to see what they hit?

quote:

So without having to read the entire thread, is there any consensus yet on exactly what happened?

simple answer is no

we know a lot about the damage to each vessel, we know a lot about Crystal track over time.

The two big unknowns:

1. DDG 62 track over time

2. Decision making by those controlling each ship and reports by watchstanders

quote:

Originally posted by bigdeal:
So without having to read the entire thread, is there any consensus yet on exactly what happened? I'm struggling mightily with how this could have happened given the agility of the Fitzgerald and what I would like to believe is the expertise and training of her crew.

As there is no information as to the track, course, speed, etc of the destroyer, there isn't any way to reach a conclusion about it, except in your imagination. Activity aboard the Fitzgerald, whatever may have happened, doesn't fit expectations.

How fast can a DDG 51 class come to a stop from full speed?
.
.
.
.
.
.
.
.
.
20 seconds

video at:

https://www.youtube.com/watch?v=IuXOr4Z9RDI

another article at:

http://foxtrotalpha.jalopnik.c...-the-burk-1681758438

If they're feathered, each screw acts as a speed brake, a maneuver known as a "crash-back." That allows the 9,000-ton destroyer to go from around 36mph to a dead stop in about 20 seconds.

quote:

Originally posted by sdy:
How fast can a DDG 51 class come to a stop from full speed?
.
.
.
.
.
.
.
.
.
20 seconds

video at:

https://www.youtube.com/watch?v=IuXOr4Z9RDI

another article at:

http://foxtrotalpha.jalopnik.c...-the-burk-1681758438

If they're feathered, each screw acts as a speed brake, a maneuver known as a "crash-back." That allows the 9,000-ton destroyer to go from around 36mph to a dead stop in about 20 seconds.

That is a little more than two lengths at ~30+ knots.

Which is sports car like performance on a ship that size. Two lengths is still less than a nautical mile by a lot, doubt they were running that fast regardless, and they shouldn't have even been that close to begin with.

yes two lengths at ~30+ knots

For the stopping distance, as a rough estimate, since they go from say 35 mph (30 knt) to zero, the DDG 51 must come to a stop in about a ship length

I didn't realize they could stop this fast, and they do it w/o damaging the ship.

For the night of the collision, 10 knt speed is probably close to what they were doing

quote:

Originally posted by sdy:
yes two lengths at ~30+ knots

For the stopping distance, as a rough estimate, since they go from say 35 mph (30 knt) to zero, the DDG 51 must come to a stop in about a ship length

I didn't realize they could stop this fast, and they do it w/o damaging the ship.

For the night of the collision, 10 knt speed is probably close to what they were doing

Well, I wouldn't say there is "no" damage. I bet they have to buy all new China in the wardroom every time they do it.

I recall reading that an aircraft carrier at flight ops going to dead stop takes something like 20 miles. I've never tried it, of course.

quote:

Originally posted by mbinky:
So if the freighter saw the destroyer, tried to signal the destroyer, then struck the destroyer, why did they wait so long before turning around to see what they hit?

My thought too.

have been using the Crystal draft markings as a ruler

the bulbous bow is big. estimating 12 ft across (horizontal direction)

So it punched a big hole

adding: The admiral said the gash was almost to the keel. Makes sense with the size of the bulbous bow. DDG 62 draft listed at 31 feet, but a lot of that is because of SQS 53 bow dome

quote:

Originally posted by mbinky:
So if the freighter saw the destroyer, tried to signal the destroyer, then struck the destroyer, why did they wait so long before turning around to see what they hit?

Who knows, but my thought is the Crystal is a huge ship and the commercial shipping lane there is very busy, some 400 ships a day I've read. Maybe ... MAYBE they wanted to be sure of not colliding with another vessel in executing a course change. Doing a u-turn in a busy shipping lane isn't a normal maneuver for a ship the length of 2 1/2 football fields. The AIS plots I've seen don't show any other ships but the Crystal and possibly where the Fitzgerald might have been. Had to be more ships in the area, prudent to avoid.

^^^^
They still could have used the radio to report a collision.

You don't go back full emergency from ahead flank often. We did it a couple times during trials.

Granted, collision avoidance would be a good time, but you have to be aware of the collision to avoid it.

quote:

Originally posted by billnchristy:
You don't go back full emergency from ahead flank often. We did it a couple times during trials.

I did it once.

a sub surfaced in front of the ship and there was no where to go as we were just coming out of Charleston Harbor and private ships were everywhere.

The OOD was looking aft(outside of the bridge) and the helmsman froze...

I walked over to the 1MC and announced to brace for collisions and I pulled both handles to the rear.

The Skipper magically appeared in a puff of smoke and was looking at me like I had killed the Pope.

After everyone got up from hitting equipment and other bulkheads...I was able to explain to the Skipper why I had done it.

He pulled me to the side and thanked me for not allowing the OOD to hit a sub, asked me to be quiet about it and nothing happened to me..even though we destroyed a reduction gear.

I was a GM2 at the time, and was standing a JOOD (navigator) watch.