By Louise Heren (Reybridge Films Ltd)
You may want underwater comms for a range of reasons - so divers can physically talk to each other, to the surface or for a presenter to do pieces to camera underwater. This can get expensive so only hire underwater comms if you really need it.
It's vital during a live underwater shoot for the gallery to be able to talk to the cameraman and presenter to direct them.
Extra training needed
Presenters can wear a range of helmets or face masks to allow them to give decent audio quality underwater comms, but they can't just pop them on and go diving, they need to be trained for physical and safety purposes, and that takes time, so remember to budget and schedule for it if you're doing an underwater shoot.
The most expensive option is a bubble helmet where the camera can see the whole of the presenter's head and face and the presenter is breathing air pumped into the glass dome and can talk freely and look around them easily, turning as shoals of fish etc. swim past. This type of helmet requires a lot of safety training and your presenter needs to be a very experienced diver who has undergone the specific training to use this helmet. It's also heavy and unwieldy and therefore, not for the faint-hearted. And it takes a while to rig, so allow lots of time.
You can also use an AGA mask, which has an enlarged face mask with mouthpiece incorporated. This gives the camera a better view of the presenter than it would get with a standard SCUBA mask, and allows your presenter to talk to you, although the sound is distorted and has that classic underwater bubbly effect. It's cheaper than the bubble helmet, but does need some training and a reasonably experienced diving presenter to use it. This is the kind of comms mask that your dive team might use too so that they can talk to each other or to the surface.
However, most divers use an internationally recognised system of hand signals to "talk" to each other underwater, and other signals that they've worked out between themselves when you've got divers who've worked together a lot.
Underwater to surface signals, if necessary, are usually via tugs on a rope, e.g. two tugs means we're coming up, three tugs means we're moving on etc.
There's new kit out all the time, so if you need underwater comms for your team or presenter, then talk to your cameraman or dive supervisor. They'll best be able to advise you on what you need and can afford for your shoot, and where to get it.