Visible crew/equipment: After Will puts the explosive inside skeletal Jacoby he exclaims, "No fair!" before he and the two other pirates blow up. In the very next shot of Barbossa, as he duels with Jack, the edge of the large wood plank that Geoffrey Rush and Johnny Depp stand on near the pile of treasure is plainly visible at the bottom of the screen. It can also be seen on DVD 2. (This is ONLY visible on the video version.)
Visible crew/equipment: After Elizabeth hides the dinner knife in the napkin, two shots later, as Barbossa hands the medallion to the monkey, there are two rods visible below the swing - one at each end - to keep the swing steady. (Visible on VHS.)
Visible crew/equipment: When Elizabeth is first taken aboard the Pearl you can see the yellow coloured contact lenses that Captain Barbosa is wearing.
Answer: The curse needs the blood of everybody who took a coin from the chest. All the other pirates have already contributed so, as the movie opens, the only blood needed is Will's, substituting for his father. During the finale of the movie, Jack takes a coin from the chest, adding himself to the curse, so his blood is now required as well as Will's.
Tailkinker ★
But I didn't see any blood on the coins, and none of the pirates cut themselves, even before Will became part of the mix.
Yes, the other pirates did cut themselves before Will came into it, off-screen. The lack of blood on the coins can simply be explained as most of it dripping to the bottom of the chest, it being washed away by storms blown into the cave, or by the fact that they didn't drop that much blood on it in the first place.
When they had Elizabeth they believed she was Bill Turner's daughter, but they all thought the curse had failed, none of them had cut themselves so it makes zero sense.
They had been collecting back the coins for years. During that time they repaid their own blood. All they needed was the last coin and the blood of Bill Turner to break the spell.
lionhead