I'm not sure of the protocol up north, but whenever I dive off a boat I always tip the mate/DM. Five bucks a tank seems fair. I'm pretty self-sufficient but I appreciate someone that gets up early to put the tanks on the boat, helps me up off the bench, takes my fins, helps me back to the bench, put water and fruit on board for the surface interval, etc etc. Getting a dive boat ready for a good day of diving is a lot of work.
Nearly all the mates/DM I have worked with work really hard to provide an enjoyable dive experience. They know where the sea horses, frog fish and other cool fauna hang out. If I'm spending a couple of thousand bucks on a dive vacation an extra hundred for the crew is not a problem.
I don't show my DM or Instructor card when I'm on vacation - I'm on vacation.
Nearly all the mates/DM I have worked with work really hard to provide an enjoyable dive experience. They know where the sea horses, frog fish and other cool fauna hang out. If I'm spending a couple of thousand bucks on a dive vacation an extra hundred for the crew is not a problem.
I don't show my DM or Instructor card when I'm on vacation - I'm on vacation.