In essence not really!
The fleet would have to have access to sheltered water - sheltered not just from the weather but also from 'bad people and things'.
Seaplanes have landed offshore - and some of them have actually taxied or beeen towed home - but the sea state needs to be very reasonable - so this adds a massive constraint.
Seaplanes made a lot of sense when building long runways was difficult or expensive, now that is comparatively easy with the mechanised equpment we have. The constraints in terms of payload, operations (weather, maintenance, support etc) simply make it all too hard to be worthwhile