A Second World War tank boat for island campaigns

Which Second World War navy and tank turret would best suit an armoured tank boat?

Japan is the likeliest user because of its island campaigns, probably with a compact one-man Japanese tank turret.

The question sends the idea of an armoured tank boat back to the Second World War and asks which turret and navy would suit it. Japan is the likely builder because its forces were already planning around island campaigns and amphibious movement. A compact Japanese one-man tank turret would be a practical weapon for the small platform rather than a much larger conventional naval mounting. The boat is specialised support for contested littoral operations, not a substitute for a tank or warship in open battle. Its usefulness comes from matching a limited design to the geography and operational problem a navy actually faced.