Scuba dive or snorkel?
Snorkelling and scuba diving are both means of breathing under water so you don’t have to surface for each breath. Snorkelling limits you to remaining on or very close to the surface but requires very little equipment, while scuba diving uses pressurised air to let you go deeper and stay down far longer.
It’s often been suggested to simply extend your snorkel with a hosepipe or similar. While this sounds like a great idea, the laws of physics and biology mean your lungs cannot suck in air when your head is deeper than 18in under water. The air pressure at the surface is much less than the weight of water squeezing your lungs, and your lungs are not strong enough to inhale against it. Using a pipe longer than 18in also means a swimmer would be reusing the same air with an increasing CO2 content, which can lead to a dangerous lack of oxygen. Systems that send compressed air down from the surface to a breathing regulator are achieving the same thing as a scuba set and this risks of breathing compressed air at depth remain exactly the same.
Scuba diving is not a solo activity and should always be done in pairs. When working under the boat, it is possible for your buddy to be on board rather than in the water alongside you as long as you have a safety line. If you know what you are doing and how to mitigate the inherent risks, scuba diving is incredibly safe. A lack of knowledge or experience is the most dangerous thing.
There are a number of ‘spare air’ products on the market, as used by America’s Cup teams. These are really only for emergencies and an inexperienced diver will use up the air supply within just a few breaths, so they aren’t a practical solution on board.
Scuba diving
Scuba diving will let you spend a much longer time under water, which means you can do more major jobs like clearing a badly fouled propeller or checking the anodes and skin fittings. Scuba diving is not that complicated and learning is not hard, but if you don’t know what you’re doing and don’t understand the risks, there is the potential to hurt yourself, as with any sport. It is also a really enjoyable activity to add on to your sailing. Some of the world’s best diving is to be had in water shallower than 9m, where there is very little risk of bends. If you have a dive buddy and someone on the surface keeping a lookout, you will have the freedom to explore the amazing marine life that is found beneath the surface around the UK coastline as well as more exotic locations. It is huge fun.
Equipment
You will need a certain amount of equipment to scuba dive. The basics include an air tank with backstraps, a regulator and a gauge, but most sets will also have a buoyancy compensator device and a spare regulator. A ‘sailor’s set’ or mini-scuba setup is the most pared-down version, followed by a Mini-b and then the full scuba set (see over for details). Alternatively, in many of the places you might want to dive, it is quite easy to hire kit and to go out with local dive boats, particularly if you’re already trained. If you are going off on a serious cruise, it is worth considering taking basic scuba diving kit with you whether you can dive or not. In remote places, you won’t be able to haul out and the chances are that someone on a boat nearby knows how to dive but doesn’t have their kit with them.
training
A bit of training goes a very long way in keeping you safe. While you can do a one-day micro-dive course to see if you like it, it only qualifies you to dive to depths of 5m with an experienced diver. The first rung on the ladder is the PADI Open Water Course. It includes theory and practical both indoors and in open water. You will be qualified to dive to depths of 18m or deeper with an experienced diver. It gives you enough knowledge to safely go under your boat with scuba gear and to make informed judgments about safety.
Over four days, you’ll learn how to wear the kit, get in and out of the water, breathe normally under water, control your buoyancy, work and communicate with your dive buddy and deal with problems like clearing your mask or giving your buddy air. These skills are sufficient to be able to scuba dive, wherever you find yourself sailing.
You should never use scuba kit without proper training. Even at 3m, you have the potential to really hurt yourself if you don’t know what you are doing.
There are other courses and bespoke training available too, as well as training for families.