I'd say the sheer fact that the Phalanx is essentially a bolt and shoot system compared to the deck penetration of the Goalkeeper is why the RN did not adopt the system further. Along with the ability for the lower weight to allow multiple mounting positions of the Phalanx.
I cannot say which is the better system in a comparison between Phalanx or Goalkeeper.
My observation is that goalkeeper has not being acquired for a new build ship of any navy for sometime.
South Korea's second ship of the Dokdo Class which is scheduled for Commissioning this year is to have Phalanx in preference to the original ship which had Phalanx.
I think whatever attributes Goalkeeper has, it's future rests only with the systems currently in service.
My take is that a CIWS is just that, a kinetic response to threats in the last couple of KM's.
At this stage layered defence has failed and you now have a few seconds for either a gun based system to perform it's magic, or have a passive defence system do the same.
I'd place short range SAM systems in a category beyond this distance.
So for the immediate future what are the realistic options for western navy's today.
I'd suggest not many.
Phalanx
Millennium Gun
40 mm and 57 mm with 3P ammunition
Any other suggestions as I think that's it in 2020
For the RAN, do we continue with Phalanx or explore other options?
Does the 40 mm on the new Arafura class suggest a window into the future for ship close in defence.
Hopefully it covers the roles of the Typhoon Bushmaster and Phalanx systems wrapped up into one defence system.
If so, we may need to look at what cannon defends the fleet for that crucial last couple of KM's
Thoughts
Regards S