It looks like they can only use the skills that reflect their current rank. Do they still have 4 skill slots or 2 for example when they are commander rank?
Boffs get one space skill and one ground skill slot per rank, so a Commander has four skills available on each side and a Lieutenant has two.
All active ground skills are available whenever the boff is with you. However, the number of skills you're actually able to use in space is determined by the seating in your ship. If you put a Commander into a Lieutenant seat, you only use the first two skills that boff has slotted.
One slot per rank, total of 4 for space and 4 ground at the same time. You can, however, train them in multiple skills in the same slot and then switch which are active to be used when you're not in combat.
If you're talking the Abilities they use on your ship, it's largely your ship that determines what ranks of abilities you can use on it. If you have a Commander 'seat' you can use all four abilities, Lieutenant Commander 'seat' is limited only 3 even if the Bridge Officer is a Commander trained in 4, Lieutenant only 2, Ensign only 1.
They can learn every skill that you have a training manual for and they will remember them forever.
You can promote them up to Commander at which point they can have 4 ground, 4 space skills that are active / usable at a time.
You can have 2 different ranked versions of the same skill active, like Beam Fire At Will I and II.
You can not place a lower ranked skill into a higher ranked slot -- an Ensign skill like Beam Fire At Will I can only be made active in slot 1
For space skills, you must assign a boff to a Station, and that Station has a limit on which ones of their active skills are available. If you assign a boff to an Ensign seat (1 slot) only their Ensign active skill can be used.
Comments
All active ground skills are available whenever the boff is with you. However, the number of skills you're actually able to use in space is determined by the seating in your ship. If you put a Commander into a Lieutenant seat, you only use the first two skills that boff has slotted.
If you're talking the Abilities they use on your ship, it's largely your ship that determines what ranks of abilities you can use on it. If you have a Commander 'seat' you can use all four abilities, Lieutenant Commander 'seat' is limited only 3 even if the Bridge Officer is a Commander trained in 4, Lieutenant only 2, Ensign only 1.
You can promote them up to Commander at which point they can have 4 ground, 4 space skills that are active / usable at a time.
You can have 2 different ranked versions of the same skill active, like Beam Fire At Will I and II.
You can not place a lower ranked skill into a higher ranked slot -- an Ensign skill like Beam Fire At Will I can only be made active in slot 1
For space skills, you must assign a boff to a Station, and that Station has a limit on which ones of their active skills are available. If you assign a boff to an Ensign seat (1 slot) only their Ensign active skill can be used.
For ground, all 4 active skills are available.