I would say that unless its stated otherwise, it would be a safe assumption that the Security Chief is also the Senior Tactical Officer--even if they are not referred to in such a position.
Though I am of the belief that it would fall to the Captain how to organise his/her/its ship. They may want to have two separate chiefs or combine them into one. The size of the ship would also be a factor. The Enterprise-D could have easily had two separate officers, but for Voyager (being a much smaller ship) it would make sense to have the posts combined.
Also on Voyager, Tuvok's console is labelled as Security/Tactical from the time they left DS9 to the time they returned to Earth. I'd therefore say that Tuvok was in fact the Chief Security/Tactical Officer. As for all the Commanders and Lieutenant Commanders listed as being KIA, for a ship that had a complement of 141 when it left the Alpha Quadrant, having so many would seem to be a little preposterous in my opinion.
Anyways, just my thoughts.
-Bry
Though I am of the belief that it would fall to the Captain how to organise his/her/its ship. They may want to have two separate chiefs or combine them into one. The size of the ship would also be a factor. The Enterprise-D could have easily had two separate officers, but for Voyager (being a much smaller ship) it would make sense to have the posts combined.
Also on Voyager, Tuvok's console is labelled as Security/Tactical from the time they left DS9 to the time they returned to Earth. I'd therefore say that Tuvok was in fact the Chief Security/Tactical Officer. As for all the Commanders and Lieutenant Commanders listed as being KIA, for a ship that had a complement of 141 when it left the Alpha Quadrant, having so many would seem to be a little preposterous in my opinion.
Anyways, just my thoughts.
-Bry