Russian ballistics missile submarines can dive much deeper than the US ones

Russian ballistics missile submarines can dive much deeper than the US ones

This is partly true; the “Alfa” class was (at one time) thought to be able to defeat the Mk37 and early-mod Mk48 torpedoes simply by diving beneath their maximum depths. (The “Alfa” was also very fast, faster than some older ASW torpedoes, as was the “Papa”, another titanium hulled sub albeit just a one-off developmental model.) The Advanced Capabilities (ADCAP) mod to the Mk48 eliminated this advantage. The hull itself was irrelevant to an impact; neither a steel nor titanium hull would survive a torpedo hit.

Just as a preface, US Navy submarines depth (usually quoted as “greater than 400′) is a secret, as is the Russian Navy’s. So there are no hard numbers in my answer.

(Delfin aka “Delta-IV” class SSBN)

(Ohio class SSBN)

Soviet SSBNs were probably somewhat inherently stronger as they had more transverse bulkheads than American designs. This would add some, but not much, to the pressure hull’s depth limit. This is just an educated guess…

Materials is the same no matter where you ar

Different design, alloys and construction techniques will result in the creation of submarines with different propertie

Each time a boat dives the hull is squeezed and when it comes up it expands. The same thing happens on aircraft. In time this expansion and contraction builds up metal fatigue and cracks and will eventually fai

The UK and US subs are typically designed to operate at about half their crush depth. As with any engineering you include safety factors. Given this a sub could exceed its designed crush depth but it will have shorten the design life of the boats

The USSR simply did not operate any thing to the same safety margins as the wes

So, given the above it is more than possible that USSR Subs may have gone to depths deeper than western subs. However, I would not have wanted to b it...l.s.e. ot...l.s.e.ont...l.s.e.to be in one

I think how this whole question possibly began is that many defense journals, like Jane’s Fighting Ships, show a huge disparity in the maximum and crush depths. This is due to how the two navies delineated this.

In the US Navy, “Test Depth” is the maximum the submarine can repeatedly dive with no degradation to hull openings and no danger above that of submerging at all. “Crush Depth” is a calculated depth where catastrophic failure and/or loss of the submarine becomes likely. Inbetween these is ambiguous…..maybe nothing will happen, maybe something will go wrong, maybe the sub will be lost.

Depending on the era, “Test” was between 45% to 60% of “Crush”, with the latter calculated from the former.

In the Soviet navy, there was “Operational Depth” which was the deepest peacetime and/or normal operations limit, then “Maximum Depth” which was a point that anywhere beyond, degradation including total loss of the submarine was likely. “Collapse Depth” was the depth at which total loss of the submarine was 100% certain.

So using that criteria, the Soviet “Maximum” is going to be deeper than the American “Test”, and the Soviet “Collapse” is going to be much deeper than the American “Crush” as it is comparing a mathematical certainty to a possibility. Just a final comment as a former submariner, a submarine need not suffer a massive pressure hull implosion to be lost to depth. Things like a ruptured seawater valve or ingress through outboard hydraulics; normally not disastrous on their own, can destroy a submarine at great depth if they occur in short order. It doesn’t take a lot to have situations spiral out of control when the hull is already so far from the surface. A major point in the numbers is overdesign. I’ve done it every time that I design something, as do most engineers. What that means is that the contract has some specific requirements to it when something, in this case a boomer, is designed and then built. The contract says “1000m” as a made up value for where the government (Navy) wants the sub to be able to go with minimal risk. The first thing that I am going to do is to take their number and double it, because between construction and use over time, the chance of a failure is going to increase. Then I’ll add another bit as a safety margin because things happen and we all know they may have to go beyond the contract’s operating depth and parameters. We always design for well beyond the requested limits, and then reduce those on paper both for safety reasons and to cover our own hides.

Electric Boat makes mistakes and building them is never going to come out perfect. Especially the first boat of any class. (Russian sub construction suffers the same issues, and likely every ship builder out that has their issues.) Also remember that the design does in fact include the number of cycles, or dive/surface operations to the specified depth limit for the design life of the submarine. That alone means that early in life there is a much greater margin on those depth limits.
So the official values are still less than what the sub should be able to handle safely.

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