Messing about in boats since 1975.  Online Since 1997.

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Nemo & Nautilus

NEMO - A Submarine nested into a Power Cat...!  - Kasten Marine Design, Inc.
Above Aft - Docked | Above - Docked | Below - Docked
Above Aft - Deployed | Above Forward - Deployed | Below Forward - Deployed | Below Aft - Deployed

Copyright 2006 - 2014 Michael Kasten


In the links above you will observe a little wildness from our book of ultimate fantasies...

The Nemo and Nautilus are a hybrid combination of two separate vessels: a 70' surface ship and an 80' submarine. The original purpose was to develop a personal submersible yacht with long range capability. It would be equally suited to under sea tourism or scientific research.

We have so far planned the surface vessel as a catamaran / tunnel-hull craft. This 'mother ship' would nest the sub into the 'tunnel' and hold it there securely. The sub is planned to be electric drive using batteries and DC motors. The mother ship is planned to contain two generators and sufficient diesel fuel for long range, and on-station re-charging of the sub.

The idea is that with the fuel available on the mother ship, when combined the two vessels could make passages just like any other surface yacht. When mated, the facilities on the sub and on the mother ship would be available to all. When on-station, the mother ship could be moored in one spot while the sub explores, or could move along with the sub. This would allow exploration of some remote reefs unavailable to a limited-range sub, and unavailable to a surface ship just by diving - and would allow doing so for a longer duration.

When the two ships are mated, the mother ship provides power to the sub's electric drive motors, as well as to its own electric drive motors. Each could operate independently or together, i.e. the whole affair could be powered by the sub only, or by the mother ship only, or by using all three propellers from both vessels.

When deployed, the sub cruises under water or on the surface autonomously, i.e. it would not require a tether to the mother ship. When the sub is deployed, the mother ship would also be autonomous and could therefore follow the sub around, or leave to refresh supplies, or be a 'decoy' or just stay on-station, etc...

When deployed, the sub's twin fin keels are intended to allow the sub to sit on the bottom gracefully as an observation station while using very little power. Endurance of the sub is planned to be from 1 to 6 days, depending on speed and on the number of people aboard.

Alternate sub propulsion schemes are very workable, allowing greater independence from the mother ship and longer endurance. General types are diesel electric, Stirling cycle engines, and even hydrogen fuel cells.

  • The typical diesel electric sub technology is well developed, and involves a diesel generator that is run while the sub is on the surface in order to re-charge the batteries.
  • Stirling cycle engines are made by Kockums of Sweden, specifically for submarines. These are in everyday use by the Swedish submarine fleet. The Stirling engines are 'external combustion' and simply require heat from any fuel source. Diesel fuel is used in the Kockums Stirling engines, and is burned using liquid oxygen, creating an entirely air independent propulsion system. These systems have excellent endurance and the engine is silent. Typically this system is combined with batteries and DC propulsion, providing still longer range and submerged endurance.

The shape given to the sub we have shown above is aimed at achieving ultra low resistance while submerged, therefore greater speed and longer range. Submarines of this general shape and size are made by Kockums for undersea rescue and military applications. The Kockums air independent Stirling propulsion system is a compact stand-alone unit that can be integrated into new sub designs - and it's mature technology.

In the case of the proposed sub and mother ship shown above, we have planned a relatively more conventional approach to propulsion and systems, aimed at keeping the sub as simple as possible and much more economically built. We've also wished to introduce considerably more luxury than would be found on a military craft...! Both sub and surface vessels could be larger or somewhat smaller if necessary and the surface ship could be designed with other superstructure configurations or hull forms as needed.

We have received interest in this concept from various private owners as well as other entities. Nemo and Nautilus would make a perfect exploration base for a family; a stealth operation base for reconnaissance; an excellent research lab for scientific expeditions; or a deluxe dive / charter yacht.

Nemo CAT & Nautilus Submarine - Kasten Marine Design, Inc.

This concept can of course be scaled upward as needed in order to accommodate a larger expedition, or possibly underwater sub tours for larger groups, etc. We have modeled an excellent example of the mother ship at 90' overall length, the 90' Tunnel CAT.

If you are interested in this kind of wildness, please contact me for more information.