Seasick wrote:
Well first since DDG-1000 Has the Dual frequency AN/SPY-3 and volume search radar, the ships in the class can use evolved sea Sparrow as a CIWS against missiles and aircraft.
ESSM has an unacceptable minimum range and a number of other seemingly unsolvable issues that prohibits it from being used in a CIWS role. The USN has purchased a very large number of these missiles with these mechanical problems, which means there won't be any fixes. That's one of the reasons why the Navy paid Raytheon to rebuild the Phalanx CIWS production line after it was repurposed in 2005. ESSM was supposed to take the place of CIWS. It didn't work. The Navy had to go back to Phalanx, because its $2.3 Billion destroyers were starting to roll around without any defense inside 2.5 miles.
The ESSM issues have been reduced, but there are certain things it cannot get around. As a result, no; ESSM cannot be reliably used as CIWS.
Seasick wrote:
The Oerlikon 35mm hasn't been qualified for service in the USN. The USN probably doesn't want to pay for the trials necessary to qualify it, or add another supply chain for it.
It was qualified in 2005.
For general information, the Navy chose the 30mm Bushmaster over other systems (including the Millennium Gun), because the Navy had a number of Mk44 30mm turrets on order for the AAAV when it was canceled and built them into the Mk46 30mm gun system. The Navy did the cheap thing and pursued what was laying around instead of an appropriate system. The LPD-17s and LCS classes have illustrated the consistent problems with the point-and-shoot nature of the 30mm Bushmaster system, the long-lived consequences of unnecessarily cutting corners.
I offer that the unfortunate issue remains: the Navy's most expensive destroyer has no inner defense against missiles. There is an easily obtained solution: purchase the Millennium Gun from Lockheed. They are already making it for their foreign sales, and over 3000 units have already been delivered through both companies (aka supply chains exist).