Interwar giant submersible invasion crawler proposals

[Avimimus]

During thew 1930s there were some proposals for giant crawlers. These would be like land battleships - except that they would stay submerged (with water supporting their weight). They would crawl along the Ocean floor until they reached a suitable location, beach themselves and offload hundreds of troops.

However, I can't remember where I read about them... anything ring a bell?

 

[Antonio]

I've seen it on Popular Mechanics covers but are you sure this concept has ever been seriously proposed?

 

[Avimimus]

If I recall they were unsolicited proposals (with rough tonnage and performance estimates) - not officially endorsed, but officially received.

Such a design is relatively feasible compared to a 'land battleship' in the sense that it is supported by water (prior to becoming a landing-ship) and doesn't face the dramatic mobility issues of a super-high tonnage land vehicle.

 

[Jemiba]

Surely that would have been the dream of army commanders, but I can hardly see any chances of
realisation with the technology of the '30s, as lond, as it wasn't just supposed to be some sort of
submersible landing craft. But as I understand, it would have been driving over the seabed (with
no buoyancy) and to my opinion, even in litoral waters, this would require a pressure depth, that
probably would have been out of the scope of those times, especially for a vessel, which would have
needed quite a lot (and large) breaks in the pressure hull for transmissions and boarding/unboarding
hatches.

 

[bigvlada]

Average depth of La Manche is around 60 meters. It wouldn't be impossible to build something that can withstand that kind of pressure even in the thirties. Submersible transporter for the invasion of England/France perhaps?
It would be interesting to contemplate what would have happened if the Germans funded some of the hovercraft designs of the Finnish engineer Toivo Kaario? Successful execution of the Sea lion plan with hundreds of small hovercraft's instead of merchant marine vessels? Or if the allies implemented the Vladimir Levkov or Charles Fletcher's ideas? Overlord with hovercraft's instead of LST's?

 

[Avimimus]

This is quickly moving away into the speculative.

The proposal I read about was designed for relatively shallow water (coastal attacks bypassing trenches?), although I agree that it is beyond feasibility for that time period. It would still be quite interesting if anyone can turn up the article.