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Carsten, Understand that beyond a certain depth, lockout becomes unfeasible plus
the decompression times become excessive. After sailing as the engineering officer on the largest ferrocement vessel
certified for hire in the US for a year (I recognize the difference between
ferrocement and what is being proposed here) and having to repair a significant
hull breach due to the captain at the time’s inebriation (drunk), I
concur that the hull thickness should be designed greater than what is required
for depth. The vessel’s hull in the region of the accident was
properly laid up with a significant amount of rebar which held together the
crushed concrete but a large amount of water still flooded into the hull.
A freshly tarred piece of canvas pulled around the hull and over the breach
staunched most of the flooding until repairs could be made. The
square-rigger was 130 ft. (40 m.) in length, displaced about 200 t., and the
hull’s ferrocement was about 180 mm in the region of the hole. The
collision was with a channel buoy (a giving instead of a solid surface) which
crushed an area about 20 inches (0.5 m.) in diameter. The crushed
concrete had to be cleared out, the exposed concrete surface cleaned with muriatic
acid, and a VERY EXPENSIVE special epoxy-sand mixture was used to fill the area
which resulted in the patch being stronger than the surrounding hull. I am intrigued by what Wilfried has accomplished and would really like
to explore further the possibilities. To lessen the impact issue,
consider metal-skinned, external ballast tanks that vertically extend down
below the greatest breadth of the concrete hull. The metal acts as a
fender and is more forgiving of impacts than the concrete (easier and cheaper to
repair also). R/Jay -----Original Message----- Hi Jay - I was thinking on a concrete realy deep diver - and for a deep diver a diver exit chamber makes no sence. I think a concrete sub should have a minimum wall thickness to resistant local impacts like from a kai or an other ship or so. So for me it is clear that a concrete sub is someone "big". Maybe an autonomus Psub - but clear not K-Size sub. regards Carsten *********************************************************** |