Why a steering wheel on carriers?

[Dunedan]

Couldn't tell you for sure, but since I'm standing watch and bored out of my skull, here's a SWAG:

Say the aircraft ditched 100 yards off of the bow of the carrier (I dunno, but I suspect this number is generous).

The beam of the USS Nimitz is 134 feet, so figure the carrier's got to move laterally about 100 feet to avoid the misfortunate aircraft.

It's displacement is 97000 tons (which'll be something more than the mass of the ship, but I don't know by how much so I'll go with 97000 tons).

Also figure that the ship is moving about 30 knots (probably isn't, but this number will do for our purposes). At 30kt (180000ft per hour or 3000ft per minute), the ship will cover 100 yards in about 6 seconds, so you gotta move 97000 tons 100 feet laterally in less than 6 seconds. About here the math gets to complicated for me...

Any physics majors out there care to figure out how much force that would require, and is the rudder big enough to turn the carrier that fast when it's initial forward speed was 30kt?

 

[Whatsisname]

only because it's no longer mechanically linked.

Actually, the bigger the wheel the more you have to turn it to affect the rudders. The destroyers have a small basically car steering wheel on em.

 

[fc2spyguy]

only because it's no longer mechanically linked.

Not true. If it were mechanically linked a bigger wheel would still require more distance to affect the rudders than a smaller one. I imagine a bigger wheel was to get leverage.

 

[TurnandBurn55]

Ok, I'm going to give you the skinny on what I know about steering. I've been on two carriers (Nimitz and George Washington). During my times, one was the oldest and they other one was the newest. I owned steering (electrical side) on booth ships. Some mentioned that it isn't electrically connected, that would be false. Although the wooden helm isn't connected by wires, it does connect right to the synchro (which converts mechanical rotation into electrical signals). The helm moves, which synchro converts signal. Goes through amplifier (in the steering console), to 60 Hz demodulator, to the hydraulic differential. This just views were the rudders position is and what is being ordered, and then lets the hydraulic pump start to pump to move rudder. I'm not trying to sound like I'm the "man", but just wanted to show how it is connected electrically. And it really doesn't matter how fast you move the helm or "a Joystick", the pumps can only pump so fast, and the ship can only turn so many degrees per second (which I have forgot). Next, is when the carriers are built they are built pretty much exactly alike. Even the Reagan had pretty much of the same old crap the the nimitz did. Except for the ICAN system, they keep the same old parts. It gives the shipyard reasons to get more money for upgardes after first PIA. Lastly is the tradition, the navy hates to go away from things that they know work. Just look at the obsolete equipment we still use. Anyways, just my two cents on it.

*Punches the button* I believe! I believe!!!

Actually, I do seen to recall an FFG I rode on for MIDN cruise just having a small wheel the size of your palm for steering... go figure...

 

[HAL Pilot]

Ok here's a question: Can anyone legitimately tell me that, given a cold cat off the bow, the ship can turn to evade a ditching aircraft? We'll say we've got 10 knots of natural wind.

I never had to avoid an aircraft on a cold cat, but I had to avoid a F/A-18 where the pilot grabbed the stick (long time A-7 driver) and stuck it into his gut immediately as the cat fired. (please Broadsword...no more questions...don't ask why this is a no-no...wait a few days at least ) The plane made an almost perfect loop right back down towards the deck. It would have speared us if we hadn't turned.

A ship does not turn like a car. Instead, it pivots around a point. For a carrier, that is about the area of the forward elevator on the starboard side. If you get a cold cat, you immediately turn away (usually to the right). The bow will go right but the stern will go left as the ship pivots. You than quickly shift your rudder and bring the bow back to the left and swing the stern to the right. The end result is the the ship "shifts" sideways. The bow does not run over the plane and the stern does not swing into it and chew it up in the props.

You can also stop a carrier in about its length if you go to an emergency flank backing bell. But that is not the perferred method.

So yes, it can and has been done successfully many times. But it's a lot easier if the cold shot is off a waist cat.

 

[kmac]

I realize it's easier off cat 3 or 4, but given that a Cod doesn't make any clearing turn with a dual engine failure I wonder what the odds of survival are (not including the ditch itself). I'm thinking more along the lines of reaction time. Seeing the cold cat, would the boss or whoever relay the message fast enough to make a difference. I mean, after all, that's why they get paid the big bucks, right?

 

[Whatsisname]

Yes, the large wheel is to generate more tourqe so that turning is humanly possible. With a smaller wheel, it would be likely you'd need more gearboxes to make up the tourqe, so you'd end up moving it just as much, without the control the larger wheel would offer.

Not true. If it were mechanically linked a bigger wheel would still require more distance to affect the rudders than a smaller one. I imagine a bigger wheel was to get leverage.

 

[Steve Wilkins]

It's a "shoe" thing....don't even bother trying to figure it out.

That's code for "I'm an aviator and haven't the foggiest idea what you're talking about. Go talk to a SWO. They usually have the answer." :icon_smil

How fast we can turn the ship really has nothing to do with how large or small the helm is. There are many factors that affect rate of turn. For instance, ship's speed through the water, size of the ship's rudders, location in relation to ship's screws, and how quickly the hydraulic system can move the rudders all have a much greater impact than how fast you can turn the wheel.

 

[HAL Pilot]

I realize it's easier off cat 3 or 4, but given that a Cod doesn't make any clearing turn with a dual engine failure I wonder what the odds of survival are (not including the ditch itself). I'm thinking more along the lines of reaction time. Seeing the cold cat, would the boss or whoever relay the message fast enough to make a difference. I mean, after all, that's why they get paid the big bucks, right?

Normally the Conning Officer is glued to the flight ops and would see it as it happened. The Captain is in his chair watching and the OOD is in the picture. One of them would see it long before the Boss or anyone else would even have a chace to call. The reaction time is very very quick.

 

[kmac]

HAL-
Thanks for the heads up. Hopefully that situation will never happen to me. Steve, do you know about carrier turn rates and radii? It seems you would be the most qualified to answer these questions (as you have already).

 

[A4sForever]

......... given a cold cat off the bow, the ship can turn to evade a ditching aircraft?

The quick and easy answer is: the ship will probably run over you.

I qualified as OOD underway on cruise on Kitty Hawk--don't ask me why--"bonding" with my Black Shoe brethren, perhaps? The ship handling drill was to initiate an immediate turn (appropriate direction) while reversing the inboard propellers to "try" to keep the screws away from the splashed A/C.

In anticipation of running over the A/C and crew---the hope was to keep from shredding them. With an ejection seat, some good wind, and a little luck---in theory, the crew will have a better chance, but no guarantees, of course.

One of my former squadron mates paired with one of my former RAG mates punched after a cold cat--daylight--WX no factor. They never recovered either one of them---the ship ran over them. After returning from cruise the ship was put in dry-dock. Upon inspection of one of the below-waterline intake screens, they found some skeletal remains and the flight gear from one of the crew.

Very depressing...the ship had dragged what was left of him around for 4-5 months.

 

[HAL Pilot]

The quick and easy answer is: the ship will probably run over you.

I qualified as OOD underway on cruise on Kitty Hawk--don't ask me why--"bonding" with my Black Shoe brethren, perhaps? The ship handling drill was to initiate an immediate turn (appropriate direction) while reversing the inboard propellers to "try" to keep the screws away from the splashed A/C.

I was an OOD on the TR. Our drill was as I posted above. Another incident where I was OOD was an EA-6B that broke the wires and dribbled off the angle deck. I immediately turned left and swung the stern right. We pivoted around the splash point and did not run over the plane. Stoped going about 90 degrees off our original course. All 4 punched out and ended up in the water off the port side.

 

[A4sForever]

I was OOD was an EA-6B that broke the wires and dribbled off the angle deck. I immediately turned left and swung the stern right. We pivoted around the splash point and did not run over the plane. Stoped going about 90 degrees off our original course. All 4 punched out and ended up in the water off the port side.

Good job---I want you driving the boat when I get my next shot---but then again, I never will get my next shot unless we start taking B747's to the boat.

What year and/or squadron was that? Why did they break the wire? Bad wire? Off-center engagement? Bad hook? All the usual questions..........thanks.

Lucky for them they were angled-off and already halfway down the length of the ship. And lucky someone smart & quick was OOD...

 

[HAL Pilot]

Good job---I want you driving the boat when I get my next shot---but then again, I never will get my next shot unless we start taking B747's to the boat.

What year and/or squadron was that? Why did they break the wire? Bad wire? Off-center engagement? Bad hook? All the usual questions..........thanks.

Lucky for them they were angled-off and already halfway down the length of the ship. And lucky someone smart & quick was OOD...

It was somewhere between late 1990 and mid-1992. Don't remember which squadron, we were doing CQs for CVW-8 in the Hampton Roads area. I believe it was a bad wire.

Edit: My fuzzy memory thinks it was right after Christmas 1990 when we left Norfolk for Desert Shield/Storm. We brought the airwing on board and did a few days of CQs/work ups before we quit all flight ops for the mad dash to the Gulf.

 

[A4sForever]

HAL Pilot:
Thanks for the update---I was in the HNL base for 7 years before our bean counters/suits closed it. First arrived in HNL in the '50s as an Army brat and could never get the blue water, blue skies and tradewinds out of my system.

How long have you been driving for HAL?