References

Renovation and improvement of submersible P-63

The manned submersible P-63, with a rated depth of 300m, is operated by Subspirit in Switzerland (https://www.subspirit.ch).

The submersible P-63 has been overhauled and brought up to state of the art in terms of safety and reliability.
For this purpose the external structure as well as the main ballast tanks and belonging vent valves have been renewed. The battery systems have now been installed outside the pressure hull in newly designed pressure vessels. Further improvements have been made in the propulsion and in the life support systems.

The improvements in weight and space inside the pressure hull allowed for increasing the number of occupants from 4 to 5. 

The overhaul works were mainly done by Abächerli Technik GmbH. The pressure-tight battery compartments were manufactured by Jeger JAA GmbH. 

Hydrodynamic and design-optimized outer shells made of CFRP
with walk-out stainless steel deck, later substituded by buoyancy neutral polymer to gain additional buoyancy (not shown here).

Design of the outer shell and the main ballast tanks was realized in cooperation with Sauber Technologies AG.

CFRP parts were manufactured by Aerolite AG, Horw. 

New main ballast tanks made of CFRP with new, automatically closing, hydraulically operated vent valves made of stainless steel (in-house design by IBH). Valves were manufactured by Sigrist AG.

Weight optimized topstructure made of stainless steel (background).

Externally loaded battery pressure vessels, made of P355 pressure vessel steel tubes.

Battery capacity of lead acid accumulator (AGM type) in both battery tubes approx. 25kWh

Flat flange end cap for battery pressure vessels, made of super duplex steel for weight optimisation. Deflection reduced by cross bracing - shape has been FEA optimized.

Weight approx. 27 kg. Weight saving compared to flat, unreinforced covers made of P355 approx. 30 kg per cover.