@dale Welcome to the forum :slightly_smiling_face: .
I have just found this topic in “Find Online Players” so I moved it here.
… even if the attacher has other sea units set aside for bombardments?
This is against the rules, as "If sea combat occurs, all attacking and defending sea and air units present must participate in the battle. " (Rulebook Europe 1940.2, page 18).
So you are not allowed to split your attacking units forSea Combat on the one hand and Bombardment on the other hand.