If there's no auto feather and you want to meet any of the climb segments you'll have to feather the propeller manually. In fact, depending on conditions there's a real good chance it won't climb at all, after. The ATR-72-500 climbs at 400 ft a minute single engine at gross weight on a ISA standard day.
This is from another carriers FCOM, not ATR's:
....
PF: auto feather check
PM: no auto feather
PF: Manual feathering right/left (or 1/2) CL's reduce memory items.
PM: points to PL
PF: confirmed
PM: moves PL to 48 degrees PLA
PM: points to right/left (or 1/2) CL
PF: confirmed
PM: moves CL to feather/fuel cut-off.
...