I agree with Dumpsterdiver on tank replacement. As to the buddy separation, it should never happen. I just put up a second blog about being a good dive buddy, and the article has appeared in a couple of publications. Here it is:
While there are some divers who have trained and are certified to dive alone, we have all been taught that safe diving means diving with a buddy. Not only is it safer than diving alone, but sharing a dive with a partner multiplies the pleasure of the dive by having someone to share the experiences and verify the exciting encounters and sightings. I am lucky to have my wife Debbie as my dive buddy. She and I know each others dive habits, we work well together as a team, and we have become very adept at not only staying close together, but also being aware of each others position, activity, and, should they arise, issues throughout the dive.
Some people seem to think that getting in the water about the same time as your buddy, and staying in the same ocean as they are, constitutes buddy diving. They are wrong. To be a good dive buddy, someone with who other people enjoy diving and look for to diving with in the future, you should take being a buddy a bit more seriously.
A good dive buddy stays close to his or her dive partner all the time. Just how close varies with conditions like visibility, current, how well you know your buddy, whether you have dove together in the past, and other relevant factors. But on every dive, your should be close enough you can respond to your dive buddy in the event of any emergency or need for assistance arising. Emergencies are not limited to air depletion. They can include entanglement, equipment malfunction, injury, or even coming under attack from an aggressive sea creature. Stay close enough to help a buddy out.
A good dive buddy not only stays in close proximity to their dive partner, they are aware of their buddys location and activity, direction of travel if moving, and can perceive any problems, confusion, unease, or distress a buddy may exhibit as it occurs or just moments after. It doesn't take long for buddies to become separated if they are not focused on and have an awareness of where each other is and what the other is doing and how they are moving. Buddy diving is kind of like going on a date. If you take a date to a dance, it is bad manners to lose them on the dance floor. Good manners require that you pay attention to them. If you dont, you might look up to find they are no where around. Its the same in buddy diving. Pay attention to your buddy. Look around and mark your buddys' location and activity regularly, in fact, often, and better still, constantly.
Part of being a good dive buddy is being sensitive to your dive buddys feelings, including how he or she feels physically and whether they are feeling stressed or anxious about doing a dive. Dont pressure your buddy to do a dive that they dont want to do. Sometimes a diver is not comfortable doing a dive. Let it go. Similarly, if a problem arises during a dive that leads to one buddy wanting to terminate, or thumb the dive, a good dive buddy will go with them. Never leave a distressed, injured, confused, stressed out, or tired buddy to fend for themselves, even if they are surfacing and returning the boast or shore.
A good dive buddy will get acquainted with his diving partner before the dive. Sometimes we get paired up with a stranger, what some call an insta-buddy. When that happens, you need to get to know each other as divers. Talk to each other. Learn about each others experience level and last dive. Clarify the communications you will use and agree as to proximity and other buddy coordination. Discuss your objectives for the dive. Are you going to swim around like crazy people or focus on looking at the animals and their behaviors? If one or both are going to take pictures or video, discuss expectations you each have for staying close. When diving with a new buddy (or any buddy for that matter) a good dive buddy will be sure to sure to do a pre-dive safety check, familiarizing the team with each others equipment. Just like you learned to do in your basic scuba certification class. There is no need to dive with a stranger if you take a few minutes to plan together, learn bout each other and communicate about the dive.
Too often, divers who are paired up by the divemaster or boat captain, or even those who may have selected each other as buddies, will introduce themselves to each other, and then be oblivious to each other throughout the dive. That is not a good idea. A dive buddy who appreciates the importance of that role will stay close, be aware of what is going on, never have a problem with buddy separation, and be there to share air, help his buddy get untangled from the kelp, notice symptoms of narcosis, and otherwise assist as needed. If you want to have a good dive buddy, be a good dive buddy. You can do it. I know you can.
DivemasterDennis