To note, you can change how long on the surface counts before the Perdix will start another dive. I've extended it to 5 minutes iirc, as my quarry diving is sometimes shallow and it may put me on the "surface" even though we're just in very shallow water for a brief period of time before moving on to the next, deeper, destination for the dive.
As a general rule for me, if I plan to get in the water with my gear and then plan to get out of the water after doing X number of things, that's 1 dive for me. My dive in Chikin Ha cenote took us from the designated entrance, to the back where we surfaced, and then back to the entrance. That was one dive for me as my dive plan was to get in, go to the back and then come back to where we entered. I planned and executed one dive.
The short explanation of what I consider a log worthy dive:
If I get in the water and do what I planned to do for that "dive" in the water, then it was one dive. If I get out, check air supply, plan a new dive, and use the same tank if I deem it adequate for further diving, then that would be a separate dive. I I don't have to evaluate gas, change gear if appropriate, leave the water for a rest/interval, and/or plan what to do next, then it's the same dive.
As a general rule for me, if I plan to get in the water with my gear and then plan to get out of the water after doing X number of things, that's 1 dive for me. My dive in Chikin Ha cenote took us from the designated entrance, to the back where we surfaced, and then back to the entrance. That was one dive for me as my dive plan was to get in, go to the back and then come back to where we entered. I planned and executed one dive.
The short explanation of what I consider a log worthy dive:
If I get in the water and do what I planned to do for that "dive" in the water, then it was one dive. If I get out, check air supply, plan a new dive, and use the same tank if I deem it adequate for further diving, then that would be a separate dive. I I don't have to evaluate gas, change gear if appropriate, leave the water for a rest/interval, and/or plan what to do next, then it's the same dive.