SEAL Minisub: Reloaded


By Joe Buff -- Defense Tech Undersea Warfare Contributor

Since at least the '90s, U.S. Special Operations Command (SOCOM) has needed a stealthy, survivable, long endurance, shirt-sleeves-environment commando midget sub to be deployed/retrieved from the back of a full-size SSN or SSGN “mother ship.” One such project, the Advanced SEAL Delivery System (ASDS), got cancelled after years in development and at the expense of many hundreds of millions of dollars. The ASDS used an oddball (and as it turned out, inherently unsafe) rectangular cross-sectioned pressure hull, had a noisy screw, problematic batteries and an overburdened environmental control system. In late '08, the single working ASDS self-cremated while its lithium-ion batteries were recharging at its special base (Hull 1's homeport?) in Pearl Harbor.

Now, Teledyne Technologies' subsidiary in Huntsville, Alabama, Teledyne Brown Engineering, has won a $383 million SOCOM competition to start over, 16 years after the ASDS program got started, to finish developing and then “manufacture and sustain” its Shallow Water Combat Submersible (SWCS) design. Teledyne Brown last year gave SOCOM a 1:1 mockup of the SWCS's interior, and a hullform model, which were key to its success in the phase 1 competitive downselection.

Even basics of the ASDS design remained classified for many years, understandably so given the sensitivity of U.S. Navy Special Warfare ops. Pending more info being released on SWCS, such as authoritative renderings of the model's insides and outsides, we can speculate about the design, in the sincere hope and stern expectation that every lesson possible is learned from the ASDS fiasco.

(The image above is a Navy concept drawing of the craft from a couple of years ago.)

A cylindrical pressure hull seems needed for reasonable SWCS operating depth, even at the cost of headroom and elbowroom; a different configuration of main screw, rudder, planes, and side propulsors seems likely; robotic grapnels ala NR-1 or research submersibles would have great utility; externally, the SWCS will not closely resemble the ASDS. Internally, any workable midget sub will need a control compartment, a midships (to manage center of gravity) diver lock out trunk (with pressure hatches both above and below?), and a warm, dry, 1-atmosphere compartment for the commando passengers and their gear.

Electronically, the SWCS ought to borrow as much as possible from the low-maintenance, high-capability Virginia-class non-hull penetrating photonics mast, and from that operationally successful, cost effective, delivered-on-time-or-better SSN's awesome 2-man digital ship control station. In fact, the ASDS had a 2-man crew: one qualified Submariner and one Navy SEAL, cross-trained and seated side by side.

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