Quote from BOAC:
HN - I do not see it so clearly - the water, which is providing the retardation force is 'retarding' the gear also and may balance the 'inertia' of that. Only if you slowed the rest of the a/c leaving the gear unaffected by entry into the water would what you say be a 'definite'.
I wonder if you may be missing the point, BOAC, re the inertia of the heavy MLG; in particular the bogie/wheel-truck part (furthest from the pivot point). At the extreme VS thought likely, the deceleration of the belly, or centre-section, as it struck the water would be great, due to its large surface area and relatively low mass. The bogie has a high mass and small surface area, relatively speaking. The door underneath it is light and flimsy.
Chris