Handy Submarine Hull Material Comparison Chart

[tom dougherty]

Here's a comparison chart of material & strengths of various nation's submarine hull materials:

http://gentleseas.blogspot.com/2015/07/chinese-and-russian-submarine-pressure.html

Lots of other interesting information beneath the chart section as well.

Just the thing for the next time you are on "Jeopardy!" .
"Ill take submarine hulls for $400, Alex!"

[southern or]

Am I right to assume the Russian unknown metal with a rating of 170,400psi belongs to the titanium Alphas? Also, why does it appear that Russia and Japan have better materials then the US?

[tom dougherty]

The Alfas had test depths of 400 meters, no different than the Sturgeon class. The titanium was employed to reduce overall hull weight (thinner hull) rather than deeper diving. The Russians like to maintain high reserve buoyancy in their designs, and the Alfas were small. In the event, the titanium developed cracks in the hull over a relatively limited lifespan.

Also, why does it appear that Russia and Japan have better materials then the US?

Because they do? The US domestic steel makers have declined markedly (along with a lot of other US heavy industries). The Seawolf class was HY-100, and they ran into considerable weld problems during construction (Maybe Bill Lambing can comment on this). Also, the US has had HY-130 for some time, but the expense and learning curve for welding very large structures with these metals is significant. Deeper diving submarine need a whole suite of changes incorporated such as improved hull fittings and penetrations, ballast tank air pressure etc. In the case of the Virginia class, we returned to HY 80 to keep costs down and produce more units at a reduced cost which is one of the big success stories in military procurement. The latest units ran about 1.7 billion a piece vs. the 2.2 billion of the lead ship.

[tsenecal]

none of this appears to show the titanium(s) being used by the US, France, Japan, Russia, or China for the research subs that have dive depths of 6000 meters or more...

[tom dougherty]

I think it is limited to combat submarines, not research vehicles.

[wlambing]

All of the HY- family steels have their quirks and problems regarding forming and welding. Periodically a 688 will be laid up for major weld repair work due to stress cracking. It's a tricky world to live and play in!!! Titanium is even snarkier, and I think was a major factor in the USSR spending themselves into bankruptcy back in the '80s. We use the stuff in small quantities where we can keep a real tight hold of quality in the production process. Still a might expensive, but in the long run you can pack more goodies into your boat and go forth into harms way
with some good assurance your own boat won't do you in!
Have a great Veterans Day, thank one, and think about who made it so and why you are free to do what you do!

Bill

[southern or]

Didn't the Aussies and the Britts use fiberglass at one point? I'm a little surprised, Aluminum was also used at one point.

[tom dougherty]

Thanks, Bill for the answer, and thanks for the time you spent in the Silent Service.

[wlambing]

'glass for superstructure only. Aluminaut was the only aluminum hulled sub I know of. Way special experimental craft. Aluminum surface craft are constantly being fixed, and usually end up getting retired early!

PS- You're welcome!!! B^)

[tsenecal]

hijacking again... knew i had seen it somewhere... some vague specs on Alvin's new sphere

https://youtu.be/a5aQ4W9GbpU?t=32 for about 1 minute. she states the sphere is 3" thick. my understanding is the presses end up making bowls 5" thick, those were precision milled down to the 3" thicknes. after that, a bevel was milled at the edge, and layer upon layer of titanium weld bead was built up, with each layer flouroscoped for cracks. that was finally ground down to the same level as the rest of the sphere after all the welding was done.

[tom dougherty]

The new titanium sphere will permit Alvin to reach 20,000 ft. This is the same depth that the now retired Navy Sea Cliff reached in 1985 (which looks externally a lot like Alvin but had a titanium sphere 30 years ago).
Spherical shapes can take higher pressures for a given thickness of material than long tube shapes such as submarine pressure hulls.

[southern or]

'glass for superstructure only. Aluminaut was the only aluminum hulled sub I know of. Way special experimental craft. Aluminum surface craft are constantly being fixed, and usually end up getting retired early!

PS- You're welcome!!! B^)

Thanks! I know Aluminum was a one off and I wouldn't have thought of using aluminum just because I've seen AG grade aluminum metal fatigue. I thought the Oberon-class used fiberglass for more?

As for Alvin, poor Alvin. The Alvin of the past will have very little in common with the new Alvin. It's pretty much a new sub. Sea Cliff was an Alvin class sub (now parts for Alvin), but they weren't identical subs. If the money hadn't come through for WHOI Alvin would've been retired too. It is a little funny that Alvin got near complete refit for something like 8 times less then the cost of a combat sub.

While we're talking about hulls, any word on if and when they'll be rehulling the Ohios? Is Twain moving forward with rehulling the Guppys? No, that isn't a joke,Guppys are still in service.