HMS Astute, the first of seven new submarines, was delivered two years late, was well over budget and thus far is not yet in service, despite being delivered in 2009.  Her career has been marked by elements of both comedy and tragedy.  In October 2010, the Astute was practicing dropping off commandos when it ran aground off Skye in full view of the Skye Bridge.  Embarrassing and not very stealthy. When it was towed off, it collided with a tug boat. Then on her first day back at sea following repairs, she broke down and had to be towed back to port.   In April of 2011, a sailor aboard the Astute killed on officer and wounder another in a shooting rampage during a goodwill visit to Southhampton.  Only a month later, the sub was gain under tow back to port after a major hydraulic failure.

It s now being reported that the submarine cannot maintain design speed and could have trouble keeping up with the fleet that it is supposed to protect.  There have also been reports of flooding during a routine dive, corrosion in   equipment, nuclear reaction monitoring instruments of the wrong type and concerns that the periscope is flawed.

HMS Astute: nuclear submarine beset by design problems and construction failures