Ha, watched two more F13s (3 and 4) yesterday and writing up about them just a day afterwards and the curse of the F13 blurring memories is already starting again.

Was PART 3 the one with the inflatable dinghy that Jason stabs his machete through but that keeps on floating regardless to re-appear in a later scene? And those bikers? They were in PART 4?

Yep, I think they were but no wonder I could never tell them apart, let alone remember which ones I had seen before.

Watching a 3-D production in 2-D also serves as a painful reminder why 3-D sucks. Too much is focused on short gimmicky effects as opposed to a stringent overall atmosphere.