American Scout C-2 Freighter
She's 135cm LOA.
I used two 6V 7Ah SLA batteries as 'useful ballast'.
She was also stuffed with doohickeys making noises, smoke, lights and moving gun turrets and radar.
Watching your build with interest.
Cheers, Doug😎
PS The sub is 107cm LOA. 1/72nd scale Type 1A U25, also from 1936.