The SEAHAKE Mod 4 ER long-range torpedo (aka DM2A4) (above and below) has a range of at least 140 km. It features an advanced electrical propulsion system and a fiber optic cable for torpedo guidance and communication, which, in conjunction with advanced signals processing and mission logic, makes the torpedo largely countermeasure resistant. Its long at 6.6m (22 feet) long. With that range it may be a viable torpedo tube deliverable medium-large UUV.
The following are parts of an article by Christopher P. Cavas in DefenseNews, November 27, 2015:
[Retired Vice Adm. Michael Connor, a former commander of the US Navy’s submarine forces, spoke to House Seapower subcommittee on October 27, 2015]
LONG RANGE TORPEDOS
Connor specifically wants torpedoes with ranges of more than 100 miles. [the SEAHAKE Mod 4 ER long-range torpedo has a proven range of 140 km, achieved in March 2012. Since then improvements in battery and fuel cell technology would mean even longer ranges. Meanwhile the US Mark 48 torpedo may still be restricted to 50 km.]
“This is definitely doable with chemical-based propulsion systems and will likely soon be achievable with battery systems,” he said. Such a range also will need better command-and-control systems, including the ability to communicate with the torpedo, perhaps via manned or unmanned aircraft or by satellite, he said.
“The torpedo will come to be considered along the line of a slow-moving missile,” he said, “with the advantage that it is more difficult to detect, carries a much larger explosive charge and strikes the enemy beneath the waterline, where the impact is most severe.”
LONG RANGE ANTI-SHIP MISSILES
Connor also wants the US “to get back into the business of submarine-launched anti-ship missiles” with the ability to “confidently attack a specific target at sea at a range of about 1,000 miles [see two competing options: an update of the old, reliable Tomahawk or the new Long-Range Anti-Ship Missile] We should be pursuing this more aggressively than we are.”
UNMANNED UNDERSEA VEHICLES (UUVS)
Connor also wants better and more-capable undersea vehicles.
“We need to improve the endurance of the vehicles, expand the payload set, and get to the point where any submarine can recover the mission data, if not the vehicle. We need to do this while keeping the cost of the vehicle down. The cost should be low enough such that, while we would always like to get the vehicles back, it is not a crisis if we don’t. The value is in the data, not the vehicle.”
Bryan Clark, a naval analyst with the Center for Strategic and Budgetary Assessments, appeared alongside Connor and urged greater development in undersea sensors — onboard submarines, unmanned vehicles and weapons, as well as deployed [SeaWeb like] in the water and fixed on the seabed.
…Clark [as ever talked up large UUVs] urged continued development in a wide range of unmanned underwater vehicles (UUV), including looking at ways to arm some. He pointed to the compact, very lightweight torpedo — now under development — as having potential not only as a defensive, anti-torpedo weapon but also as a weapon that could be carried and launched by larger UUVs. See WHOLE ARTICLE