Too Big to Dive?

22 June 2010 By Erica Lay, PADI Master Scuba Diver Trainer

Lots of people carry around a few extra kilos, but what do you do if the charter guest or the owner is obese and wants to dive...and they want you to take them?

Scuba diving does not have a maximum weight limit. However, it is a sport and most sports requires a certain level of fitness to participate. Every active diver should undergo a medical examination once a year to demonstrate physical compliance.

Being a bit chubby is not the issue here. Obesity, however, can pose danger as it often goes hand in hand with heart problems, high blood pressure and diabetes, all of which require a doctor’s approval to dive. When diving with a Scuba Centre, a medical form usually will be filled out as part of the guest registration process.

Diving on a yacht is a little bit different. If a charter vessel offers dive activities, a medical questionnaire should be an item that the charter team insists on as part of the pre-trip paperwork. The vessel instructor/divemaster should keep a copy of this for his/her records and dive logs.

It’s a bit trickier for crew on private vessels when asking the boss to fill out and sign a medical questionnaire. If the yacht has a manager, enlist him/her to help and if not, ask the captain. Keep in mind: insurance policies on vessels offering diving facilities may stipulate that all divers (certified or otherwise) must provide a medical certificate or the policy is null and void.

There are many heavy divers who’ve been diving for several years and know their limits and abilities. A good instructor helps them to enjoy the sport, whilst being aware of any risks. A diver responsible for taking other certified divers out will first speak with them to establish experience and comfort levels.

People with a larger body mass tend to use air quicker. This is not always true as a seasoned larger diver may be better at air consumption than a thinner, less-experienced diver; this changes person to person. The simple science is: obese divers have to move themselves through the water and the bigger the body, the more drag created therefore the more energy required thus more air consumed. It is best to take an obese diver shallow on the first dive to keep an eye on their gauges and see how they cope.

Hyperthermia (overheating) can be a problem for obese divers, especially when the weather´s warm but the water is cooler. Instruct divers not put their wetsuits on until the last moment and carry out briefings in the shade and ensure no one will overheat.

When saturated, body fat can store five times as much nitrogen as water, however, fat tends to have a poor blood supply, so obese divers are no more or less likely to experience Decompression Sickness (DCS). Keep in mind however: if the diver is doing several dives over a short period of time or diving at altitude then the risk factor greatly increases.

Be wary of surface swims and check the currents before diving using a weighted line. Even the fittest divers can struggle in strong currents, so err on the side of caution. Any diver could become stressed if their limits are pushed and that is when things go wrong.

An obese diver is more buoyant than the average diver and therefore, s/he needs a substantial amount of weight to sink and achieve neutral buoyancy. John, a dive instructor in The Bahamas says finding the right weight system is important, “I’ve had to put two long weight belts together to make one large enough to fit round someone; it’s not ideal and it’s very uncomfortable for the wearer! I recommend buoyancy compensators, BCDs, with integrated weight systems. We can load up the BCD and put on a weight belt.”

Weight belts can be obscured by bellies, but weight pockets are easier to ditch in an underwater emergency. Carrying all that lead around the middle will affect the diver´s trim (position in the water); spreading the weight out can help. Also try steel tanks instead of aluminium to help the weight distribution.

There are lots of tricks to ensure diver feel secure and relaxed, which will of course allow them to enjoy the dive. At the end of the day you can’t tell a guest s/he can’t dive because s/he’s fat – if his/her doctor approves, it is your jobs to ensure the dive is as stress-free as possible. Always keep in mind the risks, use common sense and have fun.