From time to time dive charters will offer double tank dives. This means you load your gear on the boat, along with a second cylinder and off you go.
It is common practice to choose two sites, the first being the deeper dive. It’s old school opinion that a deep dive must be done first (debatable, but it does improve your overall dive profile). You then head off and do a dive and instead of returning to the harbour or launch site to change cylinders, you change cylinders on the boat and then move off to a new dive site.
What are the benefits?
Well, your day of diving is much shorter as you will probably have a 30 minute surface interval and then do the second dive whereas driving the boat back to shore, off loading, re loading and so on takes well over an hour in most instances.
It’s important the boat is not overloaded. A double tank dive means each diver takes up two slots on a dive rack on the boat so numbers need to be smaller, you all need to agree on where you are going and you all need to want to do both dives. This is easily arranged if you are a member of a dive club and dive often with the same people. Odds are you all enjoy similar dive sites and this makes planning easier.
