Next in our series of snippets from the Koh Tao PADI Divemaster internship we’ll take a look at how to properly weight divers.
In salty seawater most people’s bodies are roughly neutrally buoyant. In English, that means they neither sink nor float.
But since water conducts heat away from the body many times faster than air, to keep us warm whilst scuba diving we wear an exposure suit. In the warm tropical water of Koh Tao (29-30C), divers generally wear a 2.5mm neoprene ‘shorty’ wetsuit. Neoprene is a highly buoyant material, so the result is that a diver wearing a wetsuit now floats a bit.
So in order to be able to descend at the start of our dive, we need to carry some lead weights, usually mounted on a weight belt which divers wear around their waist. With an empty BCD (buoyancy control jacket) a diver is able to descend, then, when they reach the depth which they want to stay at they add a little air to the BCD to regain neutral buoyancy, allowing them to hover effortlessly and explore the dive site.
Wearing the correct amount of weight is critically important when scuba diving.
Way too little weight and you won’t be able to descend at the start of the dive. In Koh Tao, that means swimming back to the boat to get more lead weight, which wastes time and effort. Even if you have just enough weight to get down at the start of the dive, as you use up the air in your tank throughout the dive you’ll become increasingly buoyant, so may find it difficult to stay underwater later in the dive, which poses other serious problems. So it’s critical that you’re carrying enough weight.
But what if you carry way too much weight? This leads to equally serious problems. Too much weight means you’ll have to add lots of air to your BCD to achieve neutral buoyancy at depth. The weight mounted around your waist causes your body to twist, so rather than scuba diving in a horizontal streamlined position, you’re now more upright with a lot of drag. That means you’ll expend much more effort, will consume your air supply more quickly restricting your bottom time, and be at a higher risk of overexertion. Plus diving from boats here in Koh Tao, Thailand, a diver who is significantly over-weighted may find it difficult to climb back up the ladder at the end of the dive, or may need to remove their weight belt to get back on the dive boat. So you certainly don’t want to be heavily over-weighted.
Image: An over-weighted and correctly weighted diver
New divers are often unsure of how much weight they should wear. Student divers may never have dived in the ocean before so will need guidance on choosing the right amount of lead weight for scuba diving. Even seasoned divers may have had an extended break from diving and might be carrying a bit more fat, or the warm tropical water of Koh Tao means they’ll be diving with significantly different scuba equipment which again affects how much lead weight they should wear.
As a Koh Tao PADI Divemaster, you’ll need to keep an eye on the amount of weight which divers are wearing, giving help and advice to divers who need it.
So how do you know how much weight a diver should wear?
The easiest way is to perform PADI’s buoyancy check. Once you reach the dive site, with all your scuba gear on you take a normal breath and empty all the air from your BCD. If properly weighted, you should float at eye level then as you exhale will be able to descend.
Working as a PADI Divemaster in Thailand, most likely you’ll be required to do this with customers many times. As you build up experience, you’ll eventually be able to estimate the correct amount of weight for most scuba divers.
Making sure all the divers are properly weighted means you’ll have much more enjoyable dives, where the divers which you’re guiding or assisting are comfortable and controlled, with a proper streamlined position which allows them a nice slow breathing rate and long bottom times.
And how much weight should a Thailand PADI Divemaster wear?
If fun diving for yourself, you’ll want to wear exactly the right amount of weight to allow you to enjoy your dive. However, if you’re working as a PADI Divemaster in Koh Tao, either guiding certified divers on an underwater tour or assisting a PADI Instructor with the training of new divers you’ll want to change your approach.
It’s usual for PADI Divemasters to carry a couple of extra weights during dives. If a student diver or customer does discover that they’re under-weighted during a dive, you’ll be able to give them a weight which will allow them to complete their dive in comfort and safety.
That wraps up the Divemaster Internship Thailand mini-lesson on carrying the correct amount of weight. Check back again soon for more snippets from our Koh Tao Scuba Diving Internships.
