It rapidly rises then to a nigh inexhaustible pool for the larger ships.
Then limit the pool to the size of the single largest skill level any one character has on that specific ship?
Anoter way to limit it, adapted from what I've read somehere about its use (and abuse):
-Tactics skill may be used to give a modifier to oneself or any subordinate.
-To give a tactics modifier to a subordinate, they must be in communications contact (either direct, intercom or any commo means).
-The maximum tactics modifier one can give to a subordinate is limited to his/her leader skill (minimum 1).
So on a ship in combat:
-The ship's OC (and maybe the executive officer) may use his/her tactics skill to modify the dice roll for any crewmemeber (unless intercoms fail), up to his/her leader skill (or 1, if no leader skill) each.
-The pilot may only use for himself/herself.
-The chieff gunner to any gunner up to leader skill each (or 1).
-Each gunner for his/her fire.
-Etc...
NOTE: This would be a generic rule, not limited to ship combat, but also applicable to dirtside combat, so, all along this post, when I say tactics skill it also applies to ship's tactics if on a ship