Home Forums Hunting & Shooting Hunter's Campfire U.S. Aircraft Carrier Speed

The Navy experimented with double hulled ships in the late 1970's and early '80's; the space between the hulls was hollow and high-pressure air was pumped into the space. Small holes in the outer hull would allow bubbles to escape and flow around the hull, thus "lubricating" the hull/water interface and reducing friction. This had a two-fold effect - increasing speed and/or reducing fuel consumption.

The big drawback was increased hull noise as the bubbles surfaced and the compressor noise was detectable.

And, the deeper you go, the higher the water pressure and the lesser the cavitation. Go deeper - go faster!

As I recall, they ditched the concept for subs, but continued to experiment with in on surface vessels.

If I recall correctly, the bulges (sponsons) were intended to increase buoyancy as the Midway became heavier with heavier aircraft, heavier equipment modifications, etc. While they did increase buoyancy, they also resulted in the ship becoming less stable in heavy seas and rolling increased.

Yes, I once had a business partner who was the contractor's project manager on the surface ship project.

I flew off the Midway in the '80,'82 timeframe before they put the sponsons on her. She was notorious for a "Dutch Roll" when seas got a bit rough so in addition to the deck moving up and down, it would wallow left and right too...it could cause some severe vertigo and chasing of lineup, especially at night.

The American engineers came up with the idea of the sponsons at the waterline to act sort of like outriggers, thereby helping to stabilize any rolling moment.

The Japanese engineers said the extra weight that far from the centerline would cause more inertia for any rolling motion.

The American engineers said, "no it won't." The Japanese engineers said, "yes it will." "No it won't!" "yes it will!

The Japanese engineers finally gave up.

They put the sponsons on and guess what? The rolling and "Dutch Roll" got a LOT worse.

Hard to believe they would be stupid enough to try it. Bubbles are real bad if you are trying to be quiet.

Technology works and is still being used today, bubbles are so microscopic that its not like blowing ballast.

Phil

Must be fast attacks, The Pac Tridents don't use it.

It sounds like a method of boundary layer control used on aircraft. Some airplanes will have small pores in the skin in certain areas where small amounts of bleed air from the engines are pumped through to break up the boundary layer, thus reducing drag.

The boundary layer on an aircraft (or sub/ship hull) is the area right next the skin where at a microscopic level the air or water kind of "sticks" to the skin. If you can break up that "stickiness" then you can cut down on a lot of the drag so you can go faster with less power.

https://en.wikipedia.org/wiki/Boundary_layer

The 32 knot capability was less than ten years before decommissioning. And as I stated, at that point the boilers were nearly out of air, meaning that wouldn't have been a normal operating condition for the engineering plant.

Um, no..

Even the Razorback had the (at the time, new) prairie masker system which generated those microscopic bubbles to quiet the noise.. It worked too.

We were on training ops outside SD with some destroyers and it was getting close to the end. They had little trouble tracking us for the most part (WWII subs are NOT really quiet) and the Cap'n wanted to get home and have a brewski - so he gave the order to fire up the masker.

All of sudden we 'disappeared' from those destroyers, surfaced just outside 1-SD when they were still 50+ miles out and tied up an hour later.. Them destroyer boys were pizzed. We weren't 'supposed to do that'..

Cap'n basically said, "tough chit"...

Alfas were FAST but like most Soviet stuff, crap. It was SO noisy, we could pick them up just about every time they put to sea.

Departed NS Mayport FL, in JFK one calm morning with the full wing aboard. I launched in an A-7E with ship doing around 5 Kts just as we passed the breakwater. Light jet, but still impressive kick in the pants from Cat 1. Hell of a lot of fun!

Had no idea Prairie Masker was that old. Still in use today on the DDG's and CG's. They are also blowing bubbles out of another underwater part.

ETA: Since you can find it on the net, they also blow bleed air out of the screws too. Nothing to do with speed, it masks acoustic signature.

Hard to believe they would be stupid enough to try it. Bubbles are real bad if you are trying to be quiet. [/quote]Pretty much the opposite, bleed air from the turbines make the bubble layer to mask acoustics signature. Apparently works pretty well as they put a lot of money into them to ensure they work.

S-3 if memory serves was the only jet certified to launch whilst at anchor and even downwind. I've done the downwind thing and yeah, hell of a kick in the ass from the CAT!>

That was one of the aircraft I kicked off at anchor in Hurghada during Desert Storm, the other was a Hawkeye. In the middle of the war we were down to 2 cats and launching alpha strikes off 2 cats was difficult at best. We anchored off Hurghada to bring in the VRT and Tech Reps to expedite getting us back in the fight.Can't remember the importance of needing to get those 2 birds of the deck though. Supposedly a COD and Hawkeye can free deck but I never saw it happen.

I wonder what they set the cat at for a S-3 downwind launch? I would worry a Tomcat stroke might rip the launch bar/nose gear off and sling it in the water.

We did a lot of SUCAP during Desert Storm. One of our DHs took out an Iraqi Patrol Boat with a D-704 Buddy Store when the idiot right seater selected the wrong weapon station and another squadron destroyed Saddam's boat (converted DE) with a Maverick. All we needed was 10KT excess, which makes for a hell of a shot!

"Flanker Ops" (fly at anchor)