quote:

Originally posted by JALLEN:

quote:

Originally posted by erj_pilot:

quote:

Originally posted by jimmy123x:

quote:

Originally posted by sdy:
why would a crash back throw people out of their bunks ?

35 mph to 0 in 20 seconds

You can stop your car from 35 mph to 0 in about 4 seconds

think about driving your car 35 mph and taking 20 sec to stop. doesn't sound too bad

Because if you're not expecting it,such as someone sleeping, it would be like having someone sleeping on the hood of your car and doing a normal stop from 35 mph, they're going to go flying off of the hood or at least rolling fast.......loose items all over the ship are going to fall over and hit walls and stuff. A ship isn't like a car, it's angle is going to change and pitch a lot when this sudden stop happens......the props will cavitate a lot and send vibration through most of the ship also...... The ships also stresses all of it's running gear, engine and gear mounts and things of that nature.

Physics. A car stopping from 35 mph is nowhere NEAR the MASS of a ship stopping from 35 mph. Think of the difference in energy to stop the momentum of the two. Plus with rubber on the road, you have friction to slow you down. Slowing down in a liquid involves physics I can't even make up...would have to call Sheldon Cooper on that.

Why not? Jimmy makes up stuff all the time, as here.

You just lack imagination!

Well, considering I have spent more time sitting on the head(toilet) of a boat/yacht/ship than you and most of the members here have spent standing on one. There is no need for me to have to make anything up. So If you want to keep bringing up one thread out of 11,000 postings I've had, sure not everyone can be correct all of the time. The physics are very similar between a yacht and a ship. Not so much between a car and a ship. Yet most everyone on here has driven a car.

quote:

Originally posted by sdy:
35 mph to 0 in 20 sec is not a sudden stop.

watch the video. Do you see the civilians falling down ?

It is a smooth gradual slow down on a DDG 51

This isn't smashing your foot on the brake. It is controlled and gradual.

The collision w the Crystal generated much higher rates of velocity change over a very brief period of time. That is what threw people out of their bunks.

some numbers:

under constant deceleration, from 35 mph to 0 in 20 sec would mean the ship traveled 513 feet.

The deceleration would be 2.6 ft/sec^2

The same numbers apply if you stopped your car from 35 to 0 in 20 sec at constant deceleration

gravity acceleration is 32 ft/sec^2

There is nothing smooth about it, everyone is braced if you look at where their feet are in the video they are standing with pressure on their foot that's facing the stern and standing sideways to the stern of the boat similar to a linebackers stance. At one point in time the camera man cannot even keep the camera held level and pointed in the right direction.


Decelerating ANY boat/yacht/ship in just over a boat length from 35mph creates a ton of G forces in water. It's not like on land. I've done those stops (albeit on smaller stuff) but when you're decelerating a 3,500 TON ship in that distance you're going to feel the cavitation, the ship is going to vibrate and the ship is going to pitch forward and bow down.

I can't cut and paste the link right now, but just go to youtube and search "ship bending in rough seas" and look at how much large steel freighters twist and bend and change shape in rough seas, not even a panic stop or collision situation.

https://www.youtube.com/watch?v=WUDZG0NdSPA

two crash backs at the same time

DDG 94 and DDG 87

people get wet in reverse

quote:

Originally posted by jimmy123x:


Well, considering I have spent more time sitting on the head(toilet) of a boat/yacht/ship than you and most of the members here have spent standing on one. There is no need for me to have to make anything up. So If you want to keep bringing up one thread out of 11,000 postings I've had, sure not everyone can be correct all of the time. The physics are very similar between a yacht and a ship. Not so much between a car and a ship. Yet most everyone on here has driven a car.

Maybe you should have done more reading while on the can all those hours.


You attracted attention some time back with some novel and imaginative conjectures about airplanes and flying. Experienced professional pilots pointed out some disagreement with your assessments which you may have drawn from your observations from riding around in a clients airplane. Maybe this was the disappearing 777 thread. I'm a pilot myself, or was, but not a pro. Sometimes someone who hasn't done the training, done the flying, sticks out in these discussions like a sore thumb.

I have seen some similar flights of fancy on other topics, like real estate where I happen to have considerable experience. There were so many discrepancies between what you claimed was so and what I reckoned was right, the advice you sometimes offered, I have had you on ignore for a long time. In a thread like this, your posts get quoted, so I see them anyway.

There are several examples of bogus claims in this thread.

Go back and read the dialogue on the 22nd about the Iranian encounter with the patrol boats. I referred to it, you asserted "they ran out of fuel and drifted into Iranian waters. There was no other reason in that situation." Oh, yes there was, as another poster pointed out.

There was the claim about the aluminum hull. Of course there is no aluminum hull. Years ago there were some aluminum superstructure destroyers, but those are long gone, I believe. Anyway, Fitzgerald is all steel which you conceded after MikeinNC and I pointed it out.

There are others.

I know you work as a yacht captain. Were you in the USNavy? Although we sail on the same water in the same weather, there are many differences between the Navy way and the way others may do things.

We have fairly easy standards here, and knowing what you are talking about is not required, although highly prized. It would be easier on all of us if you could do this.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I know nothing about ships and collisions. However, this thread has a lot of entertainment value. Although I am not generally fond of the legal profession, I do enjoy a good argument when I see one.
I wish I had more of a silver tongue, as I truly am jealous when someone can completely skewer another without saying STFU.

quote:

Originally posted by jimmy123x:

quote:

Originally posted by sdy:
35 mph to 0 in 20 sec is not a sudden stop.

watch the video. Do you see the civilians falling down ?

It is a smooth gradual slow down on a DDG 51

This isn't smashing your foot on the brake. It is controlled and gradual.

The collision w the Crystal generated much higher rates of velocity change over a very brief period of time. That is what threw people out of their bunks.

some numbers:

under constant deceleration, from 35 mph to 0 in 20 sec would mean the ship traveled 513 feet.

The deceleration would be 2.6 ft/sec^2

The same numbers apply if you stopped your car from 35 to 0 in 20 sec at constant deceleration

gravity acceleration is 32 ft/sec^2

There is nothing smooth about it, everyone is braced if you look at where their feet are in the video they are standing with pressure on their foot that's facing the stern and standing sideways to the stern of the boat similar to a linebackers stance. At one point in time the camera man cannot even keep the camera held level and pointed in the right direction.


Decelerating ANY boat/yacht/ship in just over a boat length from 35mph creates a ton of G forces in water. It's not like on land. I've done those stops (albeit on smaller stuff) but when you're decelerating a 3,500 TON ship in that distance you're going to feel the cavitation, the ship is going to vibrate and the ship is going to pitch forward and bow down.

I can't cut and paste the link right now, but just go to youtube and search "ship bending in rough seas" and look at how much large steel freighters twist and bend and change shape in rough seas, not even a panic stop or collision situation.

You like to say you've spent more time on a yacht's shitter than I spent on the deck of a ship, fine, make your claim. I was USN, OOD and EOOW qualified. That takes some time. Only you know how much time you spent on the shitter.

I will tell you this: I have done crashbacks on a CPP ships, many times, and you should have spent more time on that shitter, because you are full of shit. You are telling people who have been there and done that IN PERSON how it's supposed to work, based on videos you've watched. Think about that before you answer.

HEY! Everyone calm down so the thread doesn't end up getting locked! If you want to piss and moan take it somewhere else.

Thank you JALLEN.

You have a way of getting your point across better than I do.

I have twice typed a response to Jimmy about his responses-yet I lack the ability to keep from just calling him a (insert sailor word here). Again Thanks.

quote:

Originally posted by petr:
HEY! Everyone calm down so the thread doesn't end up getting locked! If you want to piss and moan take it somewhere else.

^^^^^
THIS

quote:

Originally posted by jimmy123x:

quote:

Originally posted by JALLEN:

quote:

Originally posted by erj_pilot:

quote:

Originally posted by jimmy123x:

quote:

Originally posted by sdy:
why would a crash back throw people out of their bunks ?

35 mph to 0 in 20 seconds

You can stop your car from 35 mph to 0 in about 4 seconds

think about driving your car 35 mph and taking 20 sec to stop. doesn't sound too bad

Because if you're not expecting it,such as someone sleeping, it would be like having someone sleeping on the hood of your car and doing a normal stop from 35 mph, they're going to go flying off of the hood or at least rolling fast.......loose items all over the ship are going to fall over and hit walls and stuff. A ship isn't like a car, it's angle is going to change and pitch a lot when this sudden stop happens......the props will cavitate a lot and send vibration through most of the ship also...... The ships also stresses all of it's running gear, engine and gear mounts and things of that nature.

Physics. A car stopping from 35 mph is nowhere NEAR the MASS of a ship stopping from 35 mph. Think of the difference in energy to stop the momentum of the two. Plus with rubber on the road, you have friction to slow you down. Slowing down in a liquid involves physics I can't even make up...would have to call Sheldon Cooper on that.

Why not? Jimmy makes up stuff all the time, as here.

You just lack imagination!

Well, considering I have spent more time sitting on the head(toilet) of a boat/yacht/ship than you and most of the members here have spent standing on one. There is no need for me to have to make anything up. So If you want to keep bringing up one thread out of 11,000 postings I've had, sure not everyone can be correct all of the time. The physics are very similar between a yacht and a ship. Not so much between a car and a ship. Yet most everyone on here has driven a car.

Oh, yeah? Well, "I've spent more time on the shitter at test depth than you've been in the Navy. So, suck on that awhile!"

Not a dog in this fight, but you reminded me of this from my days underwater!

let's get back on topic

http://www.defensenews.com/art...estigation-continues

The collision off Japan that claimed the lives of seven sailors on the U.S. Navy destroyer Fitzgerald punched a hole large enough to drive a tractor trailer through, leaving the service with the considerable task of putting the crippled destroyer back together again.

The bulbous bow of the ACX Crystal left a 12x17-foot hole beneath the waterline, per three Navy sources who spoke on background, an enormous breach that rapidly flooded three spaces. Sailors had about a minute to evacuate their berthing, and several were awoken by salt water rushing into their rack, per two sources familiar with the details of the accident said

There is no indication that the ship sounded a collision alarm, which would have alerted sleeping crew members to the looming catastrophe, prior to the collision. Those details, however, are the subject of an ongoing Navy investigation.

The collision also significantly damaged the ship's superstructure and SPY-1 radar array on its starboard side, and flooded out a main engineering space and radio central, rendering millions of dollars of expensive gear and equipment useless.

While investigators try to puzzle out what breakdowns lead to the tragic accident, the Navy is solving a complicated engineering problem: how to secure the ship enough to get the compromised hull out of the water. And then they have to figure out just how bad the damage is, if it can be fixed and where.

Navy engineers have managed to dewater most of the spaces and are working on a patch for the wounded hull, said 7 th Fleet spokesman Clay Doss in an email.

"USS Fitzgerald is preparing to enter drydock on Fleet Activities Yokosuka early next month to conduct follow on inspections and repairs,” Doss said. “An ammo offload was completed June 25. Additional preparations include dewatering, defueling and temporary patch installation on the hull. Once the ship is docked, technical assessments will commence that will inform options to conduct long term repairs in the United States.”

The emphasis in the early stages will be to stabilize the ship enough to get it out of the water, which the Navy says will likely be somewhere between July 6 and 8. Once its out of the water, the Navy will conduct a full survey of the ship.

One potential concern, according to Navy officials, is that the force of the collision may have warped the superstructure and created an alignment issue for the ship’s SPY-1 radar. Fixing that could add an enormous sum to the repair bill and could even be cost-prohibitive, but those assessments haven’t been completed yet.

Doss declined to comment on the alignment concerns, citing ongoing damage assessments and repair planning.

Just getting the ship out the water is a task in and of itself, said retired Capt. Gordan Van Hook, who was the chief engineer on the frigate Samuel B. Roberts when it struck a mine in 1988.

“Every ship has a docking plan for when you go into dry dock,” Van Hook said in a telephone interview. “It involves putting blocks underneath the keel to support the ship. But if large parts of the hull compromised or penetrated it can create a lot of loads and stresses that the ship wasn’t meant to withstand and if you don’t do it correctly you can bend the keel or damage the strakes.”

That means the ship’s docking plan needs to be redone to account for the damaged hull. Officials believe based on preliminary assessments that the keel of the Fitz made it through the collision ok. Fixing a broken keel would be another enormous cost driver, though the Navy managed to fix the Sammy B, which had a completely fractured keel.

The most likely scenario for the repair is that the Navy will have to send Fitz home on a heavy-lift vessel, said Bryan Clark, a retired submariner and analyst with the Center for Strategic and Budgetary Assessments.

"There is no way they can get it repaired overseas,” Clark said. “What they are doing now is trying to determine whether it can be repaired enough to make it home on its own power or if they should put it on a heavy-lift ship. From there it’s going to go into a long repair period at one of the private yards.”

Clark said General Dynamics NASSCO in San Diego would be a logical place to do the repair.

I think I'll just wait for the offical report.

I bet it'll go something like this though.

(1) Failure of the DDG Bridge and CIC watch to maintain situational awareness of the surface picture in order to prevent the collision.

(2) Blahblahblahblahblah.....

quote:

Originally posted by RHINOWSO:
I think I'll just wait for the offical report.

I bet it'll go something like this though.

(1) Failure of the DDG Bridge and CIC watch to maintain situational awareness of the surface picture in order to prevent the collision.

(2) Blahblahblahblahblah.....

Bottom line would seem to be that someone on the Navy destroyer screwed up and people died.

quote:

Originally posted by Scoutmaster:

quote:

Originally posted by RHINOWSO:
I think I'll just wait for the offical report.

I bet it'll go something like this though.

(1) Failure of the DDG Bridge and CIC watch to maintain situational awareness of the surface picture in order to prevent the collision.

(2) Blahblahblahblahblah.....

Bottom line would seem to be that someone on the Navy destroyer screwed up and people died.

That would seem to be a given.

I had a chance to discuss this at some length with my brother, who did 3-4 years of WestPac cruises as a DD junior officer, watch stander, division officer who said he spend a lot of time in those very waters.

As far as we can figure, there is no creditable explanation for the Captain being in his stateroom at the time of the collision. He said the Captains he served with wanted to be notified when a contact's closest point of approach was less than 10,000 yards, along with a brief on the tactical situation ("we are burdened, recommend turning 20 degrees to port and slowing to 15 knots, etc.) and more notifications if that changed.

He said at night it was crazy active, "pretty scary" sometimes. That was nearly 50 years ago.

If ACX Crystal had not turned from 85 deg to 68 deg, it would have passed about 2500 yards south of the collision point at roughly 130am. (still pretty close even w/o the turn)

This is a contact that has been on same course/speed for 4 hours (85 deg / 18 knots)

This situation developed over a long period of time. I hope we do eventually find out what really happened on each ship.

another important input is what other traffic was in that area around the collision point.

12X17 HOLE!!!

Wow. That will let in a LOT of water. That crew did one hell of a job keeping it afloat. Dam.

I mentioned earlier that a very rough estimate of the horizontal width of the bulbous bow was 12 ft. Still don't know how far underwater the bulb itself extends.

quote:

Originally posted by sdy:
One potential concern, according to Navy officials, is that the force of the collision may have warped the superstructure and created an alignment issue for the ship’s SPY-1 radar. Fixing that could add an enormous sum to the repair bill and could even be cost-prohibitive, but those assessments haven’t been completed yet.

Ships aren't made to run into each other, much less other objects.

My cousin-in-law, retired from the Navy several years ago as a Engineering Master Chief on Tico cruisers. When the Port Royal ran aground off of Honolulu Airport in '09, I was in Hawaii several months later and met up with them for dinner. He commented that just running aground, the abrupt stoppage and the keel settling on the coral reef, threw the mast off-center, warped sections of the keel, along with destroying both props, shafts, gearing, struts and the sonar dome; basically, everything below the waterline suffered some kind of damage. There was a time that the Port Royal, the last built and newest of the Tico cruisers, was slated for the early retirement list because of the all the structural damage.

quote:

Originally posted by JALLEN:

quote:

Originally posted by jimmy123x:


Well, considering I have spent more time sitting on the head(toilet) of a boat/yacht/ship than you and most of the members here have spent standing on one. There is no need for me to have to make anything up. So If you want to keep bringing up one thread out of 11,000 postings I've had, sure not everyone can be correct all of the time. The physics are very similar between a yacht and a ship. Not so much between a car and a ship. Yet most everyone on here has driven a car.

Maybe you should have done more reading while on the can all those hours.


You attracted attention some time back with some novel and imaginative conjectures about airplanes and flying. Experienced professional pilots pointed out some disagreement with your assessments which you may have drawn from your observations from riding around in a clients airplane. Maybe this was the disappearing 777 thread. I'm a pilot myself, or was, but not a pro. Sometimes someone who hasn't done the training, done the flying, sticks out in these discussions like a sore thumb.

I have seen some similar flights of fancy on other topics, like real estate where I happen to have considerable experience. There were so many discrepancies between what you claimed was so and what I reckoned was right, the advice you sometimes offered, I have had you on ignore for a long time. In a thread like this, your posts get quoted, so I see them anyway.

There are several examples of bogus claims in this thread.

Go back and read the dialogue on the 22nd about the Iranian encounter with the patrol boats. I referred to it, you asserted "they ran out of fuel and drifted into Iranian waters. There was no other reason in that situation." Oh, yes there was, as another poster pointed out.

There was the claim about the aluminum hull. Of course there is no aluminum hull. Years ago there were some aluminum superstructure destroyers, but those are long gone, I believe. Anyway, Fitzgerald is all steel which you conceded after MikeinNC and I pointed it out.

There are others.

I know you work as a yacht captain. Were you in the USNavy? Although we sail on the same water in the same weather, there are many differences between the Navy way and the way others may do things.

We have fairly easy standards here, and knowing what you are talking about is not required, although highly prized. It would be easier on all of us if you could do this.

Of course the report says something different. Bottom line is BOTH boats ran out of fuel. They both stopped running within minutes of each other and drifted into Iranian waters. Iranians were able to amazingly make BOTH boats operational considering that both had parts that were completely foreign to anything they're used to working on. SURE, there were leadership and other issues. BUT, there's a reason the "running boat" in the article wasn't towing the boat that "broke down" because it too wasn't running because it held the same amount of fuel the other boat did.

quote:

Originally posted by whanson_wi:

quote:

Originally posted by jimmy123x:

quote:

Originally posted by sdy:
35 mph to 0 in 20 sec is not a sudden stop.

watch the video. Do you see the civilians falling down ?

It is a smooth gradual slow down on a DDG 51

This isn't smashing your foot on the brake. It is controlled and gradual.

The collision w the Crystal generated much higher rates of velocity change over a very brief period of time. That is what threw people out of their bunks.

some numbers:

under constant deceleration, from 35 mph to 0 in 20 sec would mean the ship traveled 513 feet.

The deceleration would be 2.6 ft/sec^2

The same numbers apply if you stopped your car from 35 to 0 in 20 sec at constant deceleration

gravity acceleration is 32 ft/sec^2

There is nothing smooth about it, everyone is braced if you look at where their feet are in the video they are standing with pressure on their foot that's facing the stern and standing sideways to the stern of the boat similar to a linebackers stance. At one point in time the camera man cannot even keep the camera held level and pointed in the right direction.


Decelerating ANY boat/yacht/ship in just over a boat length from 35mph creates a ton of G forces in water. It's not like on land. I've done those stops (albeit on smaller stuff) but when you're decelerating a 3,500 TON ship in that distance you're going to feel the cavitation, the ship is going to vibrate and the ship is going to pitch forward and bow down.

I can't cut and paste the link right now, but just go to youtube and search "ship bending in rough seas" and look at how much large steel freighters twist and bend and change shape in rough seas, not even a panic stop or collision situation.

You like to say you've spent more time on a yacht's shitter than I spent on the deck of a ship, fine, make your claim. I was USN, OOD and EOOW qualified. That takes some time. Only you know how much time you spent on the shitter.

I will tell you this: I have done crashbacks on a CPP ships, many times, and you should have spent more time on that shitter, because you are full of shit. You are telling people who have been there and done that IN PERSON how it's supposed to work, based on videos you've watched. Think about that before you answer.

READ WHAT I WROTE. Do you have any reading comprehension??? You, yourself wrote there is lots of vibration in the aft part of the ship. Now I'm full of it for saying there's going to be a ton of vibration when doing that maneuver with propellers?

I wrote " I have spent more time sitting on the shitter than you (the person I quoted) and MOST people on the board. Most does not mean ALL members.

I HAVE DONE crash stops on many boats/yachts, with various drive systems (ALBEIT ON SMALLER BOATS). Doing a crash back with propellors you are going to get a lot of cavitation. There is no way to avoid that. With jets you don't get cavitation due to their design, just the G forces of deceleration in water. I have done crash tests on them too. A propeller is a propeller, there is nothing really different between the destroyers propeller design and any other ship, it's the same basic design. Going from full speed forward to full speed reverse is going to cause lots of cavitation and a steel ship transmits vibration and cavitation, it doesn't absorb it like fiberglass or cold molded hull construction.



Whatson WI claims to having done a crash back on a destroyer and says there is lots of vibration in the aft part of the ship.

MikeInNC "
posted June 29, 2017 09:29 PM Hide Post
quote:
Originally posted by sdy:
why would a crash back throw people out of their bunks ?

35 mph to 0 in 20 seconds

You can stop your car from 35 mph to 0 in about 4 seconds

think about driving your car 35 mph and taking 20 sec to stop. doesn't sound too bad


MineinNC"None of the ships I was on had a prop that changed pitch...so that would make a huge difference. Mostly it's not the stopping, but the damaging that occurs to the reduction gears and loose gear shifting about the interior of the vessel and smashing into stuff...a person can grab onto fixed items and would have no problem with an "All Back" order from Flank speed..."

I wrote earlier in the thread that I have never been in the Navy, nor have I ever claimed to be on a Navy ship underway. I do have LOTS of experience underway Captaining various boats/yachts/ships.

So you're telling me that if you have an opened soda sitting on the galley table and a plate of food. It's going to stay put along with all of the other loose stuff when stopping a 3500 ton ship from 35mph to 0 in 513ft? No WAY. Are you also saying when going into 30' seas that you don't have to stow any loose items on a destroyer either?

If the crew in the Navy were so bright, they wouldn't have let a warship (destroyer) come even close to getting hit by a freighter that's about 1000 feet long. It's a very unfortunate incident on all accounts. But with all of the technology on the Fitzgerald,the amount of crew it carries, and it's speed, the Crystal should've never even gotten close to the destroyer.

Just like that F16 pilot you guys keep referring back to who hit the Cessna 150, he was found at fault.