Thomas Schoene wrote:
N9NWO wrote:

It is thought that other systems are replaced, the 25mm
will become the primary light cannon round. Thus the Navy
CIWS (Phalanx) may migrate towards this round with newer
ships (ie DD-X).


There have been plenty of proposals for 25mm versions of Phalanx, but not
much interest from the Navy. They figure than if a maginal increase in
capability is needed, the 20mm Enhanced Lethality Cartridge could be
reinstated. It's always been reported as having the same effectiveness as a
conventional 25mm sabot round.

In general, however, the Navy is migrating to no gun-based CIWS at all.
LPD-17 has just RAM and 30mm Mk 46 turrets for small-baot defense. Unless
things change from what was shown at concept design, DD(X) will have 40mm
guns for close-in defnse, but not for anti-missile duties. If they do
change, I think the most likely swap will be to 30mm MK 46 turrets in place
of the 40mm, but still with no missile-defense role. For anti-missile
defense, it will rely on ESSM.

Currently it looks more like the Evolved Sea Sparrow Missile will
replace the CIWS:

Block I baseline 2 introduced further reliability upgrades and a muzzle
restraint to decrease dispersion. Installed on multiple non-Aegis and
Aegis ships, neither the original Phalanx Block 0 nor the subsequent
Block 1 baseline 0, 1, or 2 upgrades are integrated with a ship
self-defense system. A January 1992 Chief of Naval Operations decision
requires replacement of Phalanx with the new ESSM system in new
construction DDG ships. Though it initially appeared that DDG-79 would
be the first new construction DDG to receive Evolved Sea Sparrow Missile
in lieu of Phalanx, it now appears that, due to a slippage in the ESSM
development program, DDG-85 will be the first. The Navy plans to install
the Phalanx Block 1 baseline 2 configuration as temporary installations
on DDG-79 through 84 until ESSM is produced.

The RAM is mostly a Sidewinder missile platform.
The MK 46 Mod 1 30mm Machine Guns looks to be an
upgrade for the Mk 38 25mm (M242 Bushmaster). One
page for the LHP-17 showed the Mk 38 and not the Mk 46.