Submarine Superyacht

Brian, those large superyacht subs look very much like converted Russian Navy Submarines. Are they using old militay hulls or do they want to build those hulls from old Russian plans in those Russian submarine yards? With a company located in Austria, I would not be surprised.

There are not very many yards in the world with the know how in welding pressure hulls for submarines. That requires long term knowledge and experience in building military subs. I can count those yards capable of doing that with the fingers of one of my hands. And one of the best yards for building conventionell larger Subs, HDW in Kiel would refuse such a task. Our 60 meter hydrogen powered hybrid Subs (212/214 class) cost about a billion Euros a piece. Even demilitarized, they would not be much cheeper.

It might be a thrilling idea, to travel below the surface of the ocean and watch the subsea world through the window of your cabin or salon but IMHO there is a very long way from those renderings to reality. And an
incredible amount of money has to be thrown into such a project.

But those personal subs for 2 to 5 persons and depths up to 1000 ft are much more realistic and to a certain extend afordable.

As I said already in the other thread about the deepflight falcon and its sister, they are no real subs. They fly under water with negative lift (inverted wings). As soon as you stop the propulsor they pop up back to the surface because of their always positive buoyancy. As a tourist sub, real safe and a lot of fun but I question the separate single cockpits as unprepared passengers have in the past will again in the future develope claustrophobia. One prefers to be in the same compartement with the operator.

I do prefer the Dutch Uboat Worx Explorer Subs. Real submarines with ballast tanks for controlling buoyancy plus concrete ballast in case of emergency. But one of those little 3 seat devils goes for more than one million Euros already. Pretty expensive toy.

Placing some windows and a observation cabin in the buoyancy bodies of a SWATH vessel is a great idea for watching the subsea world. Much cheaper than a submarine.

Well done rcrapps

The welded steel pressure hull of a submarine is compressed when going to depth and expands again when going back to surface (same as the pressurized fuselage of an airline aircraft. The number of pressure cycles is recorded and the basis of the maintenance schedule. I wonder how a concrete hull of a submarine reacts to this type of compression and expanding. As far as I understand concrete, it is rather stiff and will break eventually. As far as I remember concrete ship, flexibility was not the most noticable property of concrete.

A finite number of cycles only applies to the viewports. Acrylic ports are limited to 10,000 cycles or 40,000 hours whichever comes first.

Surveys of the pressure hull are performed to determine if there are any discontinuities in the shape or if hull thickness has been compromised by corrosion or mechanical damage. A fatigue cycle life is calculated during design and is based on pressure and temperature but it is so far out as to be practically irrelevant ... we are talking about 30,000 cycles or so for steel hulls.

That is a dive a day for about 80 years ...

Real life experience driving deep diving manned submersibles shows that mechanical damage and corrosion are the life limiting factors.