Question for the naval guys

[mklotz]

Recently I toured the USS Midway aircraft carrier, now moored as a floating museum in San Diego harbor.

http://www.midway.org/

(BTW, if you're ever in SD, this is a must see.)

It raised a question in my mind that I've been unable to find an answer for and I'm hoping some of the naval types on the forum might be able to provide an answer.

Why is the superstructure (not sure of correct name - the part of the ship that extends above the flight deck) always on the starboard side of a carrier? Is it just tradition or is there some concrete mechanical reason for this?

 

[jpaul]

A guess.
Could it have anything to do with "Right Side Returning"? The side one steers to when ocean navigating.

 

[DICKEYBIRD]

I've never been in the Navy but my dad was a SeaBee in WWII, does that count? ;D

Maybe it was due to the P-effect of the old propeller driven aircraft? IE: full throttle, stand on the right rudder pedal to prevent the yaw to the left. If'n I were a young pilot, I'd like to think that big ol' radial engine driven prop was yawing me away from the island rather than into it!

 

[DickDastardly40]

On Aircraft Carriers the superstructure above the flightdeck is known as the island (leastways in the Royal Navy anyway)

The Officer of the Watch who has devolved responsibility for the vessel's safety at sea from the Captain has to obey the 'rules of the road'. These rules give a vessel on the starboard side right of way, so the OOW will need to be able to take a clear visual bearing to starboard to find a vessels closest point of approach (CPA) to determine whether he needs to take obvious and necessary avoiding action. On a big 'flattop' the flightdeck and the height involved would obscure a large portion of any view of the sea. Radar also does plays a big part in this procedure but close in this may also be constrained.

On ships in which have served, the Captain's cabin has always been on the starboard side and he always has a window so he can look to see what the OOW is telling him when he makes a shipping report over the intercom/phone.

In reality if an Aircraft Carrier is operating aircraft she is constrained in her course and expects everyone to get out of her way. They often have picket ships to clear the path.

 

[AlanHaisley]

There are other interesting right of way points to water traffic. For instance, a vessel under sail has right of way over a vessel under power. Of course, given that a large ocen or lake going vessel might need a mile or so to stop, it's not really wise when sailing a small boat - or even a pretty large one - to try to insist on your rights.

This one always reminded me of a set of roadside signs in Indiana when I was young:


"He was right, dead right"


"As he rolled along"


"But he was just as dead"


"As if he'd been wrong"


Burma-Shave

 

[Bluechip]

My grandfather was on this in 1914, not an aircraft carrier as such.

Fell off something, broke both legs badly, tore two fingers off, and spent the rest of WW1 in a 'brick frigate' the term I think, doing some not very WW1 stuff.

Always cursed his 'war pension', never increased I believe, of Two Shillings and Four Pence per week

http://en.wikipedia.org/wiki/HMS_Engadine_(1911)

Dave

 

[Foozer]

Recently I toured the USS Midway aircraft carrier, now moored as a floating museum in San Diego harbor.

Its a biggie all right. Back in 72 I worked at Hunters Point Shipyard, Midway Coral Sea and Hancock (getting old, memory going) were both in dry dock. Going to the bottom of the dock, walking under the carrier and touching its bottom is one sure fired way to feel SMALL.

One of them two was the one that someone dropped a bolt into the reduction gear, that's one big piece of metal, just big, the nickle content alone in that one gear would hold me over forever on some island with those little drinks sporting umbrella's. The other somehow lost an elevator in rough seas, seems they forgot to raise it to the flight deck level and a wave just took it away.

Ships passing "port to port" phrase I jungle myself to avoid the little dance we do deciding whose going which way when meeting a fellow walker head on.

 

[kf2qd]

The problem they would have been dealing with was torque. Give it full throttle and the plane wants to roll the opposite way of propeller rotation. Shows up in all prop driven aircradft unless they have contra-rotating props.

 

[Maryak]

I've never been in the Navy but my dad was a SeaBee in WWII, does that count? ;D

Maybe it was due to the P-effect of the old propeller driven aircraft? IE: full throttle, stand on the right rudder pedal to prevent the yaw to the left. If'n I were a young pilot, I'd like to think that big ol' radial engine driven prop was yawing me away from the island rather than into it!

Yep, in the early days of straight flight decks, no catapults, and single engine aircraft; a wave off was far easier for the pilot to turn left away rather than right away hence he didn't need a bloody great lump of superstructure in the way.

Best Regards
Bob

 

[cobra428]

I'll tell you one thing.....One heck of a design flaw to put it in the middle :big:
Tony

 

[radfordc]

In reality if an Aircraft Carrier is operating aircraft she is constrained in her course and expects everyone to get out of her way. They often have picket ships to clear the path.

Reminds me of an old joke:
The following is being transmitted around the Internet as an event that really took place, but it never happened. It is supposed to be the transcript of a communication between a US naval vessel and the Canadian government:


US Ship: We are plotting you on radar. Please divert your course 0.5 degrees to the south to avoid a collision.

CND reply: Recommend you divert your course 15 degrees to the South to avoid a collision.

US Ship: This is the Captain of the USS Coral Sea. I say again, divert your course.

CND reply: No. I say again, you divert YOUR course!

US Ship: THIS IS THE AIRCRAFT CARRIER USS CORAL SEA*, WE ARE A LARGE WARSHIP OF THE US NAVY. DIVERT YOUR COURSE NOW!!

CND reply: This is a lighthouse. Your call.

 

[ChooChooMike]

One of them two was the one that someone dropped a bolt into the reduction gear, that's one big piece of metal, just big, the nickle content alone in that one gear would hold me over forever on some island with those little drinks sporting umbrella's. The other somehow lost an elevator in rough seas, seems they forgot to raise it to the flight deck level and a wave just took it away.

I volunteer on the S.S. Lane Victory here in San Pedro (Los Angeles, CA). The Lane is a fully operational WWII Victory cargo ship. One of my duties is engine room tours. Some old salt mentioned to me that the quickest way to badly and quickly disable a ship is to drop something like a wrench or other hunk of metal into the reduction gearbox from one of the inspection ports. He said that any time there was inspection or work to be done on one of those gearboxes, there were armed guards positioned nearby to prevent anyone from trying anything funny. Probably had shoot-to-kill orders.

Its a biggie all right. Back in 72 I worked at Hunters Point Shipyard, Midway and Hancock were both in dry dock. Going to the bottom of the dock, walking under the carrier and touching its bottom is one sure fired way to feel SMALL.

The Lane Victory was in dry dock a couple of months ago and I got to steam from Los Angeles to San Diego and back with her. I took tons of pictures while she was high & dry on the drydock itself, including walking underneath. Yes, talk about feeling small ! The Lane is about 450 feet long, probably < 1/2 the size of carriers of that era and certainly more modern carriers. Uber cool experience !!

(Yeah pix are crappy from my cell phone, my SLR pix are much better)

Recently I toured the USS Midway aircraft carrier, now moored as a floating museum in San Diego harbor.

http://www.midway.org/

(BTW, if you're ever in SD, this is a must see.)

Marv is so right, this carrier and museum is a MUST-SEE in San Diego

Mike

 

[PhillyVa]

Yo...don't drop that thing on my house...I'll never find it.

Philly

 

[1Kenny]

Most airports use a left-hand landing pattern. It is my understanding that if the control tower (island) is on the starboard side, the air traffic controller can see all the aircraft in the pattern with out having to keep turning in a circle.


http://books.google.com/books?id=eB...ztXiBg&sa=X&oi=book_result&ct=result&resnum=3

Kenny

 

[Hilmar]

Mike,
looking at the last picture, that is a weird rudder kinked in the middle.
Also how do they get these square wood crates under the hull?
Hilmar

 

[cobra428]

Wow, never thought that torque and P factor would be the answer. Having been a pro pilot for 10 years and having been a flight and instrument instructor all I used to say to my studends was RIGHT RUDDER (to keep it straight)!! Your right about the left hand pattern 95% of the time, there are places (for noise abatement or obstructions mostly, that have right hand patterns).
Tony

 

[DickDastardly40]

The Square crates in this instance are concrete dock blocks, they are pre positioned on the dock bottom before the ship moves into the dock in accordance with the docking plan of the ship. Some times they are steel and they usually have a wooden capping which is adjusted by wedges to get the height correct along the length of the row.

The ship moves into the dock trimmed by the stern so as the water is pumped out, the block closest to the after cut up touches first, the position of the ship longditinally is adjusted by tirfors as the rest of the water is pumped until it is sat on all the blocks, if required the horizontal shores are dropped in now.

As soon as the dock bottom is dry, vertical shores are intalled in the after cut up along the keel line and also bilge keel vertical shores if required.

 

[mklotz]

Thanks for all the answers guys.

The very first American carrier (a converted collier), the USS Langley (CV-1), seems to have solved the problem by not having any topside island at all.

http://www.history.navy.mil/photos/images/h81000/h81279.jpg

http://www.navsource.org/archives/02/020142.jpg

The (original collier) bridge remained and was positioned under the flight deck.

http://www.navsource.org/archives/02/020112.jpg

Of course, being a somewhat experimental conversion and not something expressly designed for the task at hand, it's not fair to draw any conclusions from this early example.

All photos I've found of later (American) carriers have the starboard island. Whatever drove them to that placement happened very early on and persisted. The USS Lexington (CV-2), a converted cruiser commissioned in 1927 already has the starboard island.

 

[ChooChooMike]

Also how do they get these square wood crates under the hull?
Hilmar

The Square crates in this instance are concrete dock blocks, they are pre positioned on the dock bottom before the ship moves into the dock in accordance with the docking plan of the ship. Some times they are steel and they usually have a wooden capping which is adjusted by wedges to get the height correct along the length of the row.

DD40 is correct. Another common name is "keel blocks" The ones used here are reinforced concrete with a wood cap/cribbing on top. They are about 5-ish feet tall, about 3-4 foot square. The positioning pattern as DD pointed out depends on the physical layout/construction of the particular ship.

The ship moves into the dock trimmed by the stern so as the water is pumped out, the block closest to the after cut up touches first, the position of the ship longditinally is adjusted by tirfors as the rest of the water is pumped until it is sat on all the blocks, if required the horizontal shores are dropped in now.

Ahhh, THAT would explain the differences in the depth under the bow/stern hull as the drydock was raised and lowered.

tirfors

I was wondering what those winches were called that ran the length of the dry dock, like giant come-alongs Those guide cables are clearly visible on the bow of the ship in the attached picture (below) IMG00142.jpg. They guided the ship port/starboard and guided the ship in length-wise. Divers are sent below to give guidance while the ship is being moved in and the drydock pumped out.

I stayed on deck most of the nights while the ship was raised and lowered. The whole process was absolutely fascinating for me !! I hadn't realized how flat most of the bottom of the ship is. Should have been obvious given how much time I spent in the engine room which just about the lowest part of the ship.

Mike,
looking at the last picture, that is a weird rudder kinked in the middle.
Hilmar

Yes there is. One of the ships engineers (a walking encyclopedia of Liberty/Victory ship info) explained it to me. The rudder has a little jog in it coincident with the center line of the prop. This is to compensate/even out the prop thrust/wash as it's rotating (top 1/2 of prop vs bottom 1/2 of prop) - similar to the plane propeller torque that's been mentioned in this thread.

If anyone has noticed those gray/silver rectangular blocks positioned on the hull/rudder in various places - those are the sacrificial anodes to help prevent hull corrosion.

Trivia : The propeller is just over 18 feet in diameter.

More trivia : How is the prop removed ? Partly from the outside and partly from the inside. The outside nut-looking thingie on the end of the prop is removed while the prop is supported, then the actual piece of the prop shaft that fits into the prop itself is pulled from the inside of the ship.

I should post a whole thread full of pictures, like I said, it was quite fascinating for me ! Having a friendly ship engineer around to answer questions was the frosting on the cake ;D He has been running those Victory ship engines (steam turbine) for 50+ years.

Mike

 

[DickDastardly40]

I've loads more info on docking ships if interested.

The adjustment of the dock blocks also has to take into account the declivity of the dock bottom which is lower at the caisson or dock gate opening to assist the water draining out to the pump suction well.

The last time I docked a ship the young thrusting dockyard project manager had a new fangled laser device to tell when the ship had 'sued' on the first block. The grizzled dock master who had supervised the docking of warships since the 1950's relyed on a piece of string with a wooden wedge stapled to it's heel held over the side tied off on a guard rail with the string tight and the wedge just floating. As soon as the heel of the wedge appears to lift the ship has 'sued'. The laser device was about and inch behind in accuracy and the young thruster was rather miffed.