What on earth requires $600,000 to change the deck and hangar to support a different type?
A large part of the issue will be the beartrap hauldown system, which is Sea King specific. Removing the beartrap
in toto would involve significant engineering to the deck. No doubt someone with direct experience will be able to offer more detail.
In a similar vein, while the Cyclone will (eventually?) deliver bring a more modern capability than the Sea King, there's no way the new aircraft will be able to operate in the same deck conditions as the venerable Sea King unless a 'son of beartrap' is developed...not currently part of the design spec I believe? Watching the beartrap/Sea King combo in action (on video rather than live, in my case) is highly impressive!