In the 1950s, the U.S. Navy was attempting to hold its own in the interservice struggles for resources. The Air Force seemed to have a lock on the important nuclear weapon delivery mission against the Evil Empire of the USSR.
Somebody in the Navy thought: Well, let's concentrate on a mission where we are ostensibly not competing with the Air Force. How about seaplanes? The Air Force doesn't have those, does it? (Minor note: The Air Force DID have (a few) seaplanes: The Grumman SA-16 -- later HU-16 -- Albatross amphibian used for search and rescue.)
Thus the origin of the Navy's strategic bomber seaplane in the form of the Martin P6M SeaMaster. A high-performance long-range jet flying boat that could take off from protected harbors and attack an adversary from an unexpected direction. So as to avoid a direct confrontation with the Air Force, the stated mission of the P6M was minelaying, but that was a bit of a subterfuge.
https://en.wikipedia.org/wiki/Martin_P6M_SeaMaster
The P6M program also included special seaplane tenders that would support the aircraft and there was also the thought that those island or harbor bases would require air defenses. Which naturally led to the Convair F2Y ski-equipped floatplane fighter, which had first flown earlier.
Both aircraft faced technical challenges -- operating transonic or supersonic aircraft from water was not easy. Neither airplane was fully developed, but the XF2Y-1 has the distinction of being the only supersonic seaplane to date, though only in a shallow dive.
https://en.wikipedia.org/wiki/Convair_F2Y_Sea_Dart
The whole scheme fell apart in 1959. Too expensive and too many technical challenges. The Navy's contribution to the strategic mission would come in the form of Polaris ballistic missile submarines.