Hanger Deck catapults in US Carriers

The Yorktown-class and some of the first Essex-class ships had them.

You can spot them on the early Essex ships if you notice a small a-frame looking sponson adjacent to the forward most hanger bay opening.  They would be lowered for the launches as you can see from Milarjunkie's post.

It was also the rapid improvement in RADAR that rendered the scout aircraft launch unnecessary.  

Gives a whole new meaning to "go towards the light," and not necessarily a good one.

CV-8 hornet had an athwartships catapult on the hangar deck., way up forward.

Errmm... first point is mostly immaterial. The CAs in question were the Cleveland class, and were built into independence class CVLs and had no hangar cats. As it was, the CVLs as launched had only a single cat on the flight deck and I'm pretty sure it was a different type than the powder-driven models on the cruisers.

Essex, as I said, was a special case. The class had been designed for H4 catapults, but as far as I can tell, hers were delayed and she left for the pacific with a H2 catapult (same one the Yorktown class had) on the flight deck and nothing in the hangar. She had this configuration for the entire war; there were a couple of H4s in storage for her at Puget Sound Naval Shipyard if she made it in for an overhaul, but the war ended before she made it back in.

Also good to remember that several US CV's were converted on the ways from CA's.  So, the CA catapults had often already been separately manufactured and budgeted to that hull.

In the 30's a lot of tactical doctrine was in flux, too.

All of that while practical experience was showing that seaplanes on combatants were not working out in proportion to all the money spent perfecting things like the cats.  (Seaplanes are very sensitive to sea state for landings, and are hugely fragile in recovery operations--finding a "use" for the expensive technology a good thing in tight economic times.)

Thank you all for your input. I still think it's great that there' s lot more to discover . I am now off this weekend to ScaleModel World at Telford, the annual IPMS(UK) great gettogether to eat,drink,socialise and spend money on things I didn't realise I needed so badly. 

There were two main purposes for the hangar cats. One was to allow the launching of an airplane out-of-sequence. Say you have an air group all spotted on a deck for a strike, but then need to launch a scout for some reason. Rather than re-spot the deck, they could launch from the hangar cat.

The second is in case of flight deck damage; if the structure was damaged enough such that you couldn't launch from the flight deck, there was still the hangar cat. This was the same reason that the US ships were fitted with arresting gear forward and designed to steam backwards at a high speed as well; if the aft deck were damaged, they could still recover aircraft forward.

Operationally, they weren't all that well received. Pilots hated them (engine revving in a dark hangar and then you get shot out into the light; if it's timed to the roll wrong you get shot into the water, etc), it was much slower than launching from the flight deck, and it did take up some prime real estate. Only the first Essex class received them (Essex herself did not and is a special case) and all were removed by late 1944.

Like the earlier "double flight deck" designs, it was one of those "nice in theory, but not so much in real life" ideas.

CV-8 is correct. I don't know the answer to the wind problem, but I cannot imagine it was a big one unless the wind was strong. One advantage was that the elevators at the time were centrally located, so using them precluded operations on deck.

stevebagley

My question(s) really are what use were they , how long they lasted in service , and didn't they take up more hanger space than they were worth ?   I can't see any carrier launching aircraft off the flight deck , whilst shooting them out on a different heading out of the hanger. The wind problem would be immense .

 

Some carriers were fitted with these in the 30s/40s & it seems they were used more for experimental purposes more than anything else, it seems that they weren't much used or liked operationally. Back in those days wind over the deck probably wasn't as much of a problem as the aircraft were far lighter & often during normal deck launches didn't use or require catapult assistance. Hanger deck catapults launched the aircraft from the side of the carrier, at 90° to the deck.

What the logic was I don't know, but I'm assuming it was either for launching as many aircraft as quickly as possible or for use in the event that there was a problem with the flightdeck or lifts.

More info here;

http://www.murdoconline.net/archives/10864.html

My error- should be USS HORNET CV 12 . Now I appreciate the importance of the number.