Navy question

[Hawkmoon]

An amphibious assault ship of the now-retired Tarawa class is larger and has a longer flight deck than our WW2 aircraft carriers. I know the amphibious assault ships carried Sea Harriers and are now carrying (or are slated to carry) the STOL/VTOL version of the F-35.

Question: If a Tarawa class ship were equipped with a catapult, could conventional carrier aircraft like the F-14 operate from it?

[dogmush]

Not without major overhaul and redesign. It would need cats, arresting gear, and some flight deck reinforcement at minimum,  and it still would lack the angled landing deck that modern carriers have.  The flight deck would have to be clear stem to stern during landing ops for when the planes missed the wires.

That's just the obvious issue that rises up.  There's probably 1000 little gotchas to make it impossible.  Jet blast deflectors,  clearance on the island, elevator hatch and hanger sizes, etc.

[RoadKingLarry]

My younger brother served on Tarawa,  I'll see 8f I can get a hold of him and find out.
My best guess though is that they would be hard pressed to find the space for all the big parts and steam plant that makes a catapult go. Other than that it seems like it could theoretically be possible. Arrested landings might also be tricky as again there is a lot of hidden stuff under the deck.

[K Frame]

I'd question whether the elevators would give proper clearances for a F-14.

[Parker Dean]

Knowing just enough to be dangerous on the subject, as usual, I'm going to say no. Carriers got bigger because aircraft weights and the speeds need to be able to fly with that weight was just too much for the smaller decks. I mean, you could probably get one off there with no dakka and no fuel to speak of but there's little point in that beyond ferrying.

Then getting cats on a ship like that would be a serious problem. The systems are actually huge with large tankages, cable runs, pullies, piping, etc. The steam plant would need extra capacity to operate the cats while you would also need more evaporator capacity to keep up with the added steam losses. At this point it would probably b easier to start over with another ship. I suppose emals would make fitment of a cat easier but then you'd still need to increase electrical generation capacity, which includes the steam to do it.

[French G.]

Haha...no. I served on a CVN and on LHA-4. Five years ships company on both while fixing parts for every aircraft they carried, some they didn’t and an odd hovercraft or two. Everything is different. The structure of the ship to handle the landing, cat and arresting loads. Elevators wouldn’t fit or lift the aircraft. No angled deck. Limitless fresh water and steam generation of the nuke plants. LHA was burning 40000 gallons a day of bunker just to make it go if we were in a hurry. Now you want 30 knots over the deck?

If you become familiar with both ships you realize how survivable the CVN is and how not the LHA is. I didn’t know where my lifeboat was on the carrier. We had several lifeboat musters a month on the gator. I liked to tell my Marines that all their boats were aft so they would slow the screws down before we got there. Mine was at the forward corner of the island. Great spot except for being in the middle of the bomb farm. I figure that if an LHA and its attendant smaller amphibs deliver the Marine Battalion to shore everything after that is a bonus. Maybe it partially sinks level and you can still land a helo on it. They just were not built to take multiple missile hits and keep fighting.

[just Warren]

odd hovercraft or two.

Did the hovercraft add any real capability or were they just there? That is someone thought they might be valuable but it turned out they weren't?

[BobR]

Haha...no. I served on a CVN and on LHA-4. Five years ships company on both

Who did you piss off, other than the detailer?

I did 3 years on the Forrestal as ships' company right after A school. I loved it but really didn't want to go back. So after shore duty I went to P3s as a Flight Engineer. That was sea duty I could live with!! :)

bob

[Boomhauer]

The Essex’s and Midways got the angled deck refit for jet aircraft but even after those updates they were not big enough for the F-14.

If you were to manage an angled deck refit like went on for those carriers for an amphibious assault carrier you’d probably wind up with something still probably not able to operate the larger jets, and that’s assuming all the structural stuff was possible

I think of the LHAs as like a modern CVL or jeep/escort carrier

[French G.]

Did the hovercraft add any real capability or were they just there? That is someone thought they might be valuable but it turned out they weren't?

Oh they are wonderful for over the horizon delivery of troops to the beach fast. Given they can haul an Abrams tank i think they are handy. There was some testbed stuff where they mounted an A-10 GAU-8 on the deck along with a rocket launcher and I think explosive line mine clearing charges to make an air cushion craft that could clear beach obstacles.  We typically operated just LCUs because of the welldeck configuration. Ones I worked on hitched rides across most of the Indian Ocean to come see me because the units don't have the capability to make the titanium hyd lines the thing uses. Much like the fix it by DHL and Fedex Osprey...

Who did you piss off, other than the detailer?

I did 3 years on the Forrestal as ships' company right after A school. I loved it but really didn't want to go back. So after shore duty I went to P3s as a Flight Engineer. That was sea duty I could live with!! :)

bob

I chose those believe it or not. I did my active time on a strict join the Navy and see Norfolk program. I was four hours from home and owned a house in Newport News for nine years. I was actually second to pick orders in A school, they did by class rank at the time. The two Marines ahead of me didn't count and Mr. #1 picked stupid orders. I later saw him again in Mech magazine after he learned the wrong way to fold E-2 wings. I also passed him and graduated first which was delightful since he was so smug about his 18 month A&P school.

I really branched out for my reserve career. I went to Virginia Beach.

RTC Great Lakes, A school Millington, CVN-71, HC-2, LHA-4, VFC-12. Not a lot of places for 22 years.

[French G.]

Further perspective, the Navy spent some hundred million or so to modify the ship to carry four V-22 Osprey. They had to figure every aspect of where they could park and tie down the thing in the hangar due to the structure of the ship, the hangar deck essentially being the roof of the welldeck. So the whole aft end of the LHA is two walls about 20 feet wide stuffed with offices and shops. The roof is the flight deck/ceiling of the hangar. Then the hangar, then the welldeck. Big hollow box. Crappy flat hull of shallow draft. Just not much structure there. A carrier is impressive. While a lot of modern armor against missiles is just space the thing in the bowels is well put together. More of everything. The vitals are in an armored box deep in the hull, that being reactors, engineering spaces, magazines. Everything else is stuff a missile can plow through and not kill the ship.

[MillCreek]

^^^How was the flight deck modified to withstand the exhaust temps of the Osprey in vertical flight mode?

[just Warren]

Worked with a guy once who was part a crew that ran some sort of pump system.

He said it was below the waterline and that you could hear the metal of the hull flexing.

As someone who is both claustrophobic and not a fan of deep water that was slightly terrifying to hear.

Edit: He was on the Kennedy.

[French G.]

^^^How was the flight deck modified to withstand the exhaust temps of the Osprey in vertical flight mode?

I don't remember but I think they did something. I remember being limits for how long the crew could run them. Need to look up the Osprey NATOPS. Whole thing for shipboard is a huge joke. Sketchy as hell to launch and recover in all but calm seas. Not a ton of space between the salad shooters and the island. The aircraft is near unmaintainable in field conditions, wait until it gets old. 5000psi hydraulics needing special titanium lines which need the million dollar computerized bender to make, carbon fiber monocoque both skin and ribs which will take highly specialized repiar when someone pokes holes in it, the list goes on. I do not like them.

https://news.usni.org/2014/01/15/sna-2014-heat-f-35-mv-22-continue-plague-big-deck-amphibs Here is a good read on flight deck go melty. Basically a military industrial appropriations process war crime. People should be lined up and shot. We cannot use our toys because they break our other toys. Bear in mind this was after my time, I left USS Nassau in 2008. I mainly remember restrictions on how long they could run the engines at power. The harriers idled for hours above my office but the nozzles don't go down on takeoff until the very end of their deck run and they don't hover long when landing. I think the technical procedure was get about a ten foot hover established then chop throttle and allow airplane to crash. It really was that awful. I rebuilt Harrier landing gear once, never been so nervous for my quality assurance certs. Musta done it right, not in jail.

[French G.]

Worked with a guy once who was part a crew that ran some sort of pump system.

He said it was below the waterline and that you could hear the metal of the hull flexing.

As someone who is both claustrophobic and not a fan of deep water that was slightly terrifying to hear.

Edit: He was on the Kennedy.

My last day on a carrier I was at my promotion ceremony to E-6. Also still on duty due to manning issues. The damn shaft alley flooded. So there I was a few decks down. The ships are never not trying to kill you.

[just Warren]

Slight veer:

I've read a lot of the Patrick O'Brian books, Master and Commander etc., and in one of them he made the point that there is always a certain quantity of water in the hull.

It can never be totally pumped out.

Which brings up a philosophical point: Where does the ship end and the sea begin?

And in a Horatio Hornblower book H² is in charge of taking a prize back to England, the cargo was rice and no one noticed that the prize had suffered damage below the water line so that the rice absorbed so much water the ship sank.

It's true, taking in too many carbs will bring you down.

[Hawkmoon]

And in a Horatio Hornblower book H² is in charge of taking a prize back to England, the cargo was rice and no one noticed that the prize had suffered damage below the water line so that the rice absorbed so much water the ship sank.

I remember reading the same story, but it was about John Paul Jones during the American Revolution.