Hawk,
They are 6.5. At least mine were. They were alpine flush mount with no ring. I wanted to upgrade the speakers so I bought JBLs first. They are an okay speaker but the grill is fixed. So I had to mount on the outside, which was a PITA. First, removing the existing speakers without removing the entire side is very difficult. I would recommend taking the entire section off.
I have since upgraded to Polk 651MM. They are a lot better. This time I had to remove a portion of the bumper at the bottom to get the speakers to fit. BTW, I also mounted two 6.5s in boxes on the engine compartment lid. Sounds a lot better when outside the boat.
