Some time ago I was on a dive boat where the current had shifted 180 degrees. Fortunately, it had gone from strong to only moderate, but it left a fair amount of divers stuck downcurrent with a long snorkel back to the boat as the only alternative.
A handful of divers returned to the boat huffing, puffing, coughing and sputtering from what should have been just a moderate swim back to the boat.
I like to people watch and sometimes dive boats are the best place to do this. What had these divers done to make the snorkeling return difficult? Some were out of shape, others needed to streamline their gear, but I did notice some that simply did not have the right kind of snorkel.
It’s easy to understand. Snorkels are such a simple piece of gear and are not even used that often. We can easily take them for granted. But a little bit of “snorkel savvy” will go a long way in picking the right snorkel for you so that when you do need it your snorkel will perform well and make your diving experience that much more pleasant.
Tube Diameter
At its most basic value, the snorkel is just a tube, but to think that just any old tube will work is erroneous. The diameter of the tube should be directly proportional to lung capacity. If a tube is too small, obviously it will be too hard to pull air through it. What a lot of people don’t realize, however, is a large bore tube can be just as problematic. With a large tube there is a lot of “dead air.” This is air that must be moved in and out before good fresh air can reach the lungs. In extreme circumstances, a carbon dioxide build up can occur leading to headaches and shortness or breath.
Small divers should choose snorkels with a small diameter. Most scuba divers will suffice with a medium bore. Large bore snorkels are best reserved for large divers with demanding free-diving activities.
Upper Tube Curve
The drag a snorkel can add to a diver must be minimized. One of the better ways of doing this is with a good curve to the tube. The tube should wrap around the diver’s head, hugging the contours of the skull.
Tube Pipe Shape
Another way of reducing drag is with a properly shaped pipe. The cross-cut of the tube can be oval in shape with the leading edge being smaller. Again, overall drag is reduced. A well designed cross-cut will also assist in expelling water from the snorkel.