Joined: November 21st, 2010, 12:24 am

May 2nd, 2018, 7:59 pm #21

They will be incorporated into the Navy's forthcoming class of sailless SSAs (Submarine, antimatter power), which will be autonomously operated by bioelectric organic matrices built around clones of Stephen Hawking's brain.

Of course, the masts will just be backups for the underwater radio comm system....
The difference between "democracy" and "populism" is whether or not the ruling elite likes the outcome.
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Joined: November 13th, 2008, 10:19 pm

May 2nd, 2018, 9:43 pm #22

Dave AAA wrote: A sensor drone would still have to communicate in real time with a submerged vessel.  The least obtrusive and best bandwidth is to do so with a physical link.  Practically speaking, the best way to get that is to poke a mast above water.
If detected it says pretty much exactly where the mast is and cab't give you cross bearings straight away.  I don't suggest UUVs as replacing masts but as a useful supplement; they might communicate by cable, as towed sonars do, or by active broadcast to a passive mast which could then be only as large above water as receiving the signal demands.  The UUV would then be unstealthy but would not give away the exact location of a sub, just the area if there is no other explanation as to how that emitter got there.  I'd be surprised if subs cannot already passively receive data from friendly sensors / networks.
"Be harmonious, enrich the soldiers, and scorn all other men"

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Joined: May 8th, 2007, 9:56 pm

May 3rd, 2018, 2:13 am #23

The US Navy examined several sail removal alternatives in the late 1960s and early 1970s, including: 
 
  o  Folding masts and bridge that retract into a turtleback superstructure or double hull section.
 
  o  Telescoping sail and/or masts that retract into a cylindrical well in the pressure hull (similar to an open ballistic missile tube).
 
While these approaches would alleviate some hydrodynamic and acoustic problems (perhaps introducing new ones), implementation would entail massive mechanical and electrical/electronic engineering development efforts and have other deleterious effects on the ship.  Hence, sails were retained and, in spite of a continuing desire to, at least, reduce the sail size, the opposite has occurred.  The increased need for submarines to operate near the surface and have increased connectivity with the outside world (with a task force commander, for littoral warfare, special warfare, joint warfare, etc.) has increased the number of functions performed by components located in a sail.  Hence, sail size has increased from LOS ANGELES to SEAWOLF to VIRGINIA.
 
The Navy's submarine model with the above described folding masts and bridge concept is pictured on page 268 of Norman Polmar's book, "Cold War Submarines." 
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Joined: May 5th, 2006, 5:38 am

May 3rd, 2018, 2:24 am #24

The 594 class had fairly short sails, but that meant shallow periscope depth and accompanying problems maintaining depth control, so in the 637 class the sail height was increased again providing a deeper periscope depth.  Eventually the forward planes were moved back to the bow, which again helps with depth control at PD.
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Joined: January 7th, 2005, 11:25 am

May 3rd, 2018, 7:41 am #25

stanger69 wrote:
Steve Crandell wrote:
stanger69 wrote:


Yes, that’s how the current ones work.
There’s something called evolution and new technology too.
But you’re not too bright.
Right.  And all the Navy's ships can be made autonomous and warp drive installed.  It's right around the corner.

I'm an ex submariner.  You asked a question and I attempted to answer it.  I didn't realize you were just trolling.
Glad your not an engineer.
How about this?

Run the mast horizontaly down the long axis of the boat. That should be good for 250ft or so. Then trim by the stern....

😄
First boat so fitted to be called the narwhale of course 
"The stone age did not end because people ran out of stones." Ahmed Yamani
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Joined: February 16th, 2006, 8:05 am

May 5th, 2018, 10:25 pm #26

Don't forget the hydrodynamic purpose of the sail. It reduced the tendency of the sub to roll around its long axis when maneuvering. A good discussion of submarine hydrodynamics  can be found in the reports of various modifications of the Albacore (AGSS-569). 

Some of the current optronic mast are telescoping, and can be contained in the sail, needing no hull penetration, save for the wiring. 
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Joined: May 8th, 2007, 9:56 pm

May 8th, 2018, 8:56 pm #27

Matins wrote:  Don't forget the hydrodynamic purpose of the sail. It reduced the tendency of the sub to roll around its long axis when maneuvering. 

Sorry, but that is incorrect.  Other than providing a fairing around the masts, bridge trunk, etc., the sail has a deleterious impact on submarine design.  It destabilizes the boat in the horizontal plane requiring larger stern control surfaces to achieve proper longitudinal stability and, in high speed tight turns, causes the boat to roll, sometimes quite violently, a phenomenon called snap roll. 
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Joined: August 24th, 2007, 11:14 pm

June 10th, 2018, 10:21 pm #28

Huh. I always thought that the sail had a kind of "keel effect" type thingie that helped the boat resist rolling.

Silly civilian...
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Joined: January 6th, 2014, 9:49 pm

July 19th, 2018, 12:02 am #29

You could make photonics & comms masts that fold, but there'd be some serious structual challenges making it all work. You'd probably need a turtle back type strucure to house them and all the fold/erecting gear which wouldn't be much smaller or less distruptive than the sail is. You'd still need a total mas height close to what you have now (ie ~40 ft long masts) so that you get enough height above the water while still keeping the hull far enough under for control and stealth. A 40 ft mast in turn would have to be pretty good sized (rough guess, 2-3 ft diamter) at the base for strenght and stability. Fitting more than one or 2 masts that size would be a challenge. Currently most boats have 6 optical/comms masts, so you'd need quite a lot of interesting engineering to get everything to fit and you would find up with a complex difficult to silence mess. 

You also have a snorkle mast to figure out - both induction & exhaust. Each is about 18" internal diameter, so once again allowing for support you've got a 3-4 ft base diamter mast. More challenge to fit. 

This is aside from needing a place to station a surface lookout, OOD, etc. Not only do you need height for visibility, but also for weather protection. 
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