Use your hands to show something being broken into two pieces.

Chris Balogh

Cross your hands, and bring them to your neck while shaking them.

Chris Balogh

Make a squeezing motion with your hand to indicate a tightening in one of your muscles. It helps to point to the affected muscle, such as your calf. That way, your buddy can help massage it or stretch it out.

Chris Balogh

We love this one! Use your index finger like a windshield wiper on your mask lens to indicate a fogged mask. If it's your mask, it's a way to get your buddy's attention to explain why you're stopping for a moment to try and defog it (let a little water in and then clear). If you're an underwater photographer, it's a great hand signal to use when your model's mask is fogged.

Chris Balogh

Use both hands for this one — if you need to end the dive and the emergency is not serious, a simple thumbs-up ascent signal will work. But when you need assistance, use this one.

Chris Balogh

Use your hand to mimic going over the deep end or bending over.

Chris Balogh

If you're trying to indicate that you have a leak or your buddy has one, and she's not getting it, try also pointing to the source of the leak, such as an inflator hose or first stage.

Chris Balogh

The shrug of the shoulders says it all. Once you're safely back on the boat or shore, commit to brushing up on your navigation skills and to getting a compass.

Chris Balogh

If your floaty position in the water doesn't convey that you're too light, use this signal — sometimes, a buddy can spare a pound or two of lead. Otherwise, look for a piece of dead rock to tuck into your BC pocket. When all else fails, don't risk a runaway ascent. Abort the dive calmly and slowly.

Chris Balogh

Hopefully, you will never need this signal, but if you do, remain calm and "ask" your buddy for his octo.

Chris Balogh

This lets your buddy know you need to slow down or rest a bit. This can happen when you're fighting current or working too hard to do a task underwater, but sometimes, it can indicate a medical emergency. Feeling out of breath is not pleasant. Treat it seriously.

Chris Balogh

Ditto for pain. If you feel pain — or your buddy signals he is feeling pain — treat it seriously, and abort the dive. It could be the extra taco you ate before the dive, but it's better to be safe than sorry.

Chris Balogh

Chances are you'll notice a panicking diver and he won't have the presence of mind to signal he's feeling panicked — the deer-in-the-headlights eyes will be one clue, as will his desire to rip a regulator out of your mouth or to bolt to the surface. Panic, unfortunately, does happen, and hopefully, when you're with a buddy you know and trust, either one of you should be able to convey that the situation you're in has made you feel uncomfortable. Remember the mantra: Stop. Think. Act. Try to take — or encourage your buddy to take — deep, slow breaths. Deep diaphragmatic breathing can help avoid full-blown panic attacks.

Chris Balogh

It's not pleasant to feel sick underwater. End the dive — and get well soon.

Chris Balogh

Use your fist to show you are stuck tight — it could be due to kelp wrapped around your cylinder, fishing line under a pier that's caught your fins, or getting wedged into a too-tight space in a wreck. Remain calm — your buddy can disentangle you or ease you out better if you're not thrashing about like a great white shark trapped in a cage.

Chris Balogh

Most marine creature stings are more annoying than lethal, but if you're in pain, it's best to end the dive and get some first-aid treatment.

Chris Balogh

There's nothing worse than being overweighted. There are solutions, though. If you've descended and you're near the mooring pin, simply remove a couple of pounds and leave the weights at the base of the mooring. Use this signal to let your buddy know what you're doing. (Just don't forget to retrieve them when you are ready to ascend.) If you realize it as soon as you begin your descent, use this signal (again, so your buddy knows what you're doing), ascend and hand up a couple of pounds to the boat crew.

Chris Balogh

Similar to the "I'm feeling sick" signal, this one lets your buddy know you are in a bit of unpleasant distress.

Chris Balogh

Most times, you can clear a leaky mask and not miss a beat. But if you need to pause to address a balky mask, this signal gets your buddy's attention and explains why you're stopping for a moment to clear. If you're an underwater photographer and your model's mask is filled with water, it's a great hand signal to use to let her know that it will spoil the image.

Chris Balogh

This can be used for a plethora of issues: Can't clear one of your ears? Waggle your hand and then point to the ear. Feeling uncomfortable about what you're about to do — such as enter a swim-through? Waggle signal, then point to the entrance. Rental reg hurting your mouth? Well, you get the idea. This signal is pretty universally understood. The key is in indicating precisely what's bothering you.

Chris Balogh