Webster's 17th Edition shows usable first and useable second. So, either is okay.
useable and usable are both accepted, yet the proper spelling is usable. (According to most dictionaries.) I even spelled check it and useable is red so usable would be correct.
The Chambers Dictionary says usable.
That was a useable toy
Omelette IS the preferred spelling.
Artistic License. Any word is usable
Depends on the model and tanks, but 38 usable is quite standard.
pajamas (American preferred spelling) pyjamas (British preferred spelling)
About 3% of water is fresh and usable, but 3/4 of that 3% are in the ice caps and glaciers.
The usual spelling is judgment. The spelling judgement is the less-used variant.
likeable
lacy
The correct spelling of the adjective is "practical" (usable, feasible).