Three years after admitting defeat in developing the ASDS (Advanced Seal Delivery Systems, a small sub for getting SEALs to the beach), another attempt is going to be made. The new SWCS (Shallow Water Combat Submersible) will be a smaller (30 feet long, carrying six SEALs) version of the ASDS (which was a 65 foot long, 60 ton mini-submarine.) Like the ASDS, the SWCS will be battery powered and with a crew of two. The larger ASDS could carry up to 14 passengers (fewer if a lot of equipment is being brought along, the usual number of passengers is expected to be eight.) With a max range of 200 kilometers, top speed of 14 kilometers an hour and max diving depth of 200 feet (65 meters), the ASDS operates from one of the seven U.S. nuclear submarine equipped to carry it on its deck, and several British boats that will be similarly equipped. Both minisubs were equipped with passive and active SONAR, radar and an electronic periscope (that uses a video camera, not the traditional optics.) The SWCS will have a range of 160 kilometers and be able to dive to 300 feet (95 meters).
While a nice piece of engineering, each ASDS cost over $300 million. The first ASDS production boat underwent testing in Hawaii and the Persian Gulf for three years, before being declared ready for service in 2004. But problems kept cropping up, until the production of the other five was cancelled in 2006. After a decade of development, the ASDS had too many technical problems. Only the first one remained, and it sort of worked, But last November, the sole ASDS caught fire, and burned for six hours. The navy was reluctant to repair the vessel.
Apparently there was not a big demand for something like the ASDS, as there was no immediate request for a replacement design. But now, another attempt is going to be made to develop a similar vessel. The U.S. Navy, and the British Royal Navy, both still need a delivery vehicle for their combat swimmers. Both nations are still using the Mk 8, which is a World War II era design that is basically a reusable torpedo that divers in scuba gear hang on to as they are taken to shore. Both navies want the SWCS, which will recycle ASDS technology that worked, and replace the stuff that didn't. Thus the current plan is to have the SWCS in service within four years.