OBA

[Poor Yorek]

Can you use all your oba factors in the same action sequence, bombarding multiple hexes?

Yes, but only three may combined in any attack and they may not combined with onboard artillery.

I tend to disagree with campsawyer's interpretation insofar as the OP's question regarded only OBA. Rule 9.2 generally presumes 1 OBA factor attacks one hex, but then 9.3 allows two or three OBA fire values to be combined into one attack. So I believe the interpretation is that there can only be a single OBA attack (i.e. only targeting a single hex) in any given impulse, but up to three OBA factors can be used to make this single attack.

Nothing in 9.2 or 9.3 seems to suggest (note my caution, I'm not being dogmatic) that one can activate three OBA factors and fire at three separate hexes.

Of course, for on-board artillery, one can target as many hexes as one has bombardment fire units activated.