Tethered Submarines


Underwater operations (aquiculture, port construction and maintenance, drilling for oil or gas, well maintenance, etc.) are difficult, dangerous and expensive. To improve this a few things could be deployed:

·        internal combustion engines operating underwater,

·        remote controlled machines operating underwater,

·        crew rotation, with ample time, space and comfort, for rest at a location near to its work location.


Internal Combustion Engine Operating under Water

    Air for an internal combustion engine has to be taken above the water. If it is passed to the engine through some “hose”, which could collapse under pressure of water, it has to be preliminary compressed to the level matching highest level of water pressure on its way. This level could be high, when depth of operations is high.

If engine’s exhaust is passed back to the surface of the water through a collapsible hose, than it has to be at the water pressure at the level of operations, hence there is no benefit in moving it to the surface, it has to be released directly into the water.

Cost of pumping air to the engine is additional cost of operating engine under water. However, the benefit of such arrangement is huge, because it allows using liquid fuels in submerged submarines.

    Note that such passing of air from the water surface to the recipient submarine could be done in stages. First stage could be a small “ship” on the surface, which facilitates air intake. Next few stages could be submarines, which use part of passing air to run own engine and increase pressure of the air passed to the next submarine.


Remote-Controlled Worker Submarines

    It makes sense to have a “control” submarine to house people and a set of small unmanned “worker” submarines with “gripping legs” and “manipulators”, which are controlled remotely through an optical cable from the “control” submarine.

    The “control” submarine and “worker” submarines each have own internal combustion engine, hence it makes sense to enclose an optical cable in the air hose connecting the “control” and a “worker” submarines.

    When entire “assembly” of submarines moves to another area of operations, small “worker” submarines “hitchhike” on the “control” submarine. For that there are special “ears” on the surface of the “control” submarine, to which the “worker” submarines clasp.



    It makes sense to have at least two “assemblies” of submarines (“control” submarines with their attached “worker” submarines) working on the same work location. When one “assembly” works, the other “assembly” should be disengaged: it should be close to the surface, where maintenance, retooling and repairs are done.

In that location close to the surface, “control” submarines should be refueled from supply ships. Their “worker” submarines should be refueled from the “control” submarine, in the same location, while they are attached to it. Supply ships should bring supplies and materials needed for the operations in special waterproof containers and pass these containers to the “control” submarine for delivery to the work location.

That location, close to the surface, is the best place for the crew to rest. “Control” submarines should be spacious and comfortable enough to provide conditions for the rest of the crew.


Moving Between Locations

    When there is time to move to another work location, “assemblies” pair-up: two control submarines clasp to each other using special “ears” and “grippers” on their surface.

A special optical cable should connect these two “control” submarines, through which crew of one submarine could control engines and control surfaces of another “assembly”. The same cable should be used for regular communications between crews. This way, crews could rotate on the move also.

    It is reasonable to maintain the same pairing of “assemblies” for rotation during the work and for movement between locations.


Air Intake Management

    As usual in submarines, a compressed air tank should be in each “control” submarine. It should be larger than usual, though, because, in some cases, air from this tank could be used to supplement engines’ air supply from the surface.

    During normal working operations, one “assembly” is deep in the water, while another is on the surface or, most likely, close to the surface to avoid waves on the surface.

The “control” submarine, which is close to the surface, would need a special “worker” submarine used exclusively for air intake. It stays on the surface, takes in air, filters it and passes it through the air hose to its “control” submarine.

From there, air is passed to second “control” submarine and in turn to its “worker” submarines.

    When both “assemblies” move, each “control” submarine could deploy own special “worker” submarine for air intake or one such submarine could be used as during standard operations.

    Air used by crews, should be conditioned.


Standard Tether

    In such system, there are connections between “control” submarine and “worker” submarines and between two “control” submarines. They should be done with a standard Tether, which consists of a water proof air hose, with optical cable inside it and with a steel cable inside it (to assure Tether’s integrity).

It should be a niche in a submarine, where this Tether enters the submarine and where the Tether is partially stored. This niche should contain a mechanism automatically collecting and folding the unused part of the Tether inside it, when distance between connected submarines reduces.

Same mechanism should facilitate unfolding of the Tether from the niche, when this distance increases.

 Alexander Liss 10/6/2019