Even though they had an approximation of the thickness of the ice overhead, do they just try to bang their way through, and take their chances with any damages to the sail?
“And that reminds me of a story that's so dirty I'm ashamed to think of it myself.” — Groucho Marx
The sub shown in the film was actually the U.S.S. Ronquil, a WWII fleet boat.
It was of course, a diesel electric sub. As such, it was incapable of going under the ice... Well, let me back track-- I suppose you could take it under the ice, but it would be a foolish risk to go under the ice just on battery power with limited air.
The sail of the Ronquil was modified twice-- from a WW II Fleet boat, to a "Guppy" step sail, and finally, a fiberglass "Highsail" in 1962 or so.
Even if you could take a diesel under the ice, that sail could not be used to to "shoulder" aside ice when surfacing.
Nuclear subs had specially strengthened sails that would allow them to break through the ice in the manner shown in the film.
So yes, it was realistic in method and execution, just not with that sub.
You can usually tell when you're seeing a diesel stand in for a nuclear sub. Nucs usually only have one propeller and a "tear drop" hull design.
AE36
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Thanks for the post, ae36. I had always assumed that the sail of a submarine must contain a fair amount of sensitive electronic equipment -- the kind of stuff that could be thrown out of calibration (or worse) by "head butting" the sail into ice overhead. In fact I was wondering if they don't first float up a charge of TNT or something, to break up or at least weaken the ice, THEN take the sail on up.
But from what you're saying, I guess the engineers at New London must have thunked up a specially hardened sail that can withstand bashing up through the ice. (Just want to make sure our tax dollars aren't being put to unnecessary risk!)
The sub was nuclear. They could just as easily pump out hot water from the reactor, melt the ice and break the crust as on the movie.
shareI have never been in the Navy, much less served on a nuclear submarine. However, I am a nuclear engineer and know the design of PWRs well. One would not want to "pump out hot water from the reactor" for a variety of reasons:
radioactivity release
release of coolant from the core
dangerous reduction of coolant volume.
I have talked to U.S. Navy submariners and they have told me that the sails are hardened to break through the ice, just as an earlier poster said.
So yes, it was realistic in method and execution, just not with that sub.That's what I would have thought, because we do know they come up through the ice at times and I guess there's only limited ways you can do it.🐭 share
Retired US nuclear submariner here, having served on three attack boats, and having surfaced under the polar ice cap. Hence a few notes:
As stated, diesel boats were not built for under ice ops, the most limiting item being the diesel engine's need for lots of air, requiring frequent surfacing to gulp said air, and the inherent power (read: distance) limits of running on batteries. If you can't surface frequently, you can't go under the ice.
Also, as stated, you would not use heated water from the propulsion plant to melt ice to surface - dumb on many levels, and not worth disclaiming.
Most, but not all, US Nuclear submarines have hardened sails built to withstand breaking through the ice. This includes being hard enough to break through several feet of ice without being damaged, and also includes the ability to retract the many items that stick up through the sail (e.g., periscopes and antennae) to prevent their being damaged.
Regarding the hardness of the sail, consider that the hull of the submarine can withstand submergence pressure at over several hundred feet, so ice hardening of the sail is not a significant challenge, you just design it in.
Now, how to surface: Using upwards facing telemetry, you watch for thin places in the ice, not that it matters for more than convenience, and to protect the ship's screw or propulsor. These thin spots are called "polynyas". When you find a good one, you just go "ice pick" it, going dead slow, and let your sail top come to rest on it. It typically takes a slightly positively buoyant condition to ice pick, and you want the boat trimmed out level.
Then you do a main ballast tank (MBT) blow for a few seconds enough to become positively buoyant enough to crack the ice slowly - there is no need to waste MBT air bank air, or to "pop" up. The sail will easily crack through the ice, given that a boat has sufficient MBT volume to create several hundred tons of positive bouyancy, and that the sail is a good fulcrum.
I hope this helps.
Nucs usually only have one propeller and a "tear drop" hull design.
Hence the use of the word "usually".
Nautilus was commissioned in 1954 and was essentially a functional prototype-- at least as far as its nuclear propulsion system is concerned.
From this, the 4 "Skate Class" boats were built, between 1955 and 1959. There was also the "Barbel" class boats, 3 in all, with a tear drop hull but powered by diesel electric propulsion (basically non nuclear "Skipjacks"). "Barbel" class boats were built between 1956 and 1959.
These were succeeded by the "Skip Jack" Class: of submarines-- which had the tear drop hull design and single propeller. They were first put in commission in 1959. These design features were standard in American attack boats up to and including the Los Angles class boats.
So yes there were a few nuclear boats around before nuclear power and the tear drop hull design were married up with the Skip Jack class. U.S.S Halibut (SSGN 587) comes to mind, as does U.S.S. Seawolf (SSN 575). The afore mentioned Nautilus.
My point was that for the purposes of most movie and TV shows featuring submarines, you could usually tell a nuc from a diesel based on the design features I mentioned. Not in all cases of course.
AE36