Signal the Boat????

Hi all - I wanted to talk about signal devices. Why on earth would I need a signal device? Let me give you a good example story. I was drift diving off of Cozumel. The current was strong, waves were about 3 to 6 feet, breaking in the wind (the type of day you avoid being on the surface at all costs). We were in sight of shore, about a mile off and had a great 50 minute dive. When we came to the surface, there were two boats from the dive operation we were using. The other boat had just dropped their group and the boat captain saw our group come to the surface nearby. He came over and had a chat with the divemaster in our group and then left to follow his divers.

Our boat saw our group come to the surface, and saw the other boat moving in and thought that we were the group from the other boat. Fearing he had lost us, the captain immediately turned around to find us. The other groups boat left us and we looked at our boat going away from us as well. Of course we only got glimpses of this as we crested the waves.

The divemaster did not have an audible or surface signal with him (something to look out for when you use a dive operator and even more importantly why you should bring your own). The divemaster seeing the situation did improvise pretty well. He took his tank off and took the first stage off the tank, cupped his hand under the tank valve and expended his remaining air shooting water up in the air. The cool thing was that it looked like a breaching whale exhaling on the surface, so I hoped that at least one of the boats there would come over to investigate, but they didn't. I was the only one in the group with a surface signal tube. I inflated the tube, held it up and within about 5 minutes, the boat came over. Of course, it wasn't before several people had gotten sick on the surface.

So that is why you need a signal device. There are three types of devices and I want to talk about the pros and cons of each.

The first and most common device is the signal tube/flag. Signal tubes and flag are very visible on the surface and boats can see them from a long way off, especially if they are moving back and forth. The distance that the boat can see you from is directly related to how high you can get the device int he air and how rough the water is. Signal tubes (which can double as lift bags) can be inflated either from the bottom or through an oral inflate tube. Once inflated, you will need to hold the tube up in the air. The major issue with signal tubes is that they tend to fold in strong winds, so enter flags to overcome this issue. Flags are collapsible pvc poles with a 12"x18" colored flag on the top. Yellow is the most commonly used since reportedly it has the best visibility on the water. The drawback to flags in that you have to figure out the best way to store them on your tank since they fold down to about 27" long and 3" wide. Either device can be enhanced for night diving by adding a flasher or chem stick to the top. Make sure that your device has a clip or holder just in case.

The second type of device is audible - and is a requirement for night diving. All BCDs (at least the good ones :-) come with a whistle attached when you buy them. Make sure to leave it on. The whistle is a simple type that you can only use on the surface. Great for letting the boat know where you are if you have a flashlight failure. The other type of audible device is a "Dive Alert", which connects to your low pressure inflator just above your bcd. Once you press the button, the Dive Alert uses tank air to sound a VERY loud signal. So loud in fact, be careful with it on the surface, your ears will be ringing as I found out during a rescue session where the student was trying to inflate the training victim's bcd and accidentally pressed the Dive Alert instead and all of our ears rang for an hour. There is a version of the Dive Alert that also works underwater as a squaker as well (it sounds like a duck).

The third type is electronic. New for divers, you can now carry an electronic locator (EPIRB) similar to what boats carry to call for distress. There are two main types of EPIRBs, one with GPS and one without. The basic way they work is that as you reach the surface, you remove the EPIRB from its canister (an aluminum canister that protects it form pressure) and then pop open the device. The antenna unfolds and transmits a signal that is picked up by satellites. The satellite triangulates a rough position for the device and the appropriate rescue agency is notified (here in the US, the Coast Guard is notified for positions at sea). For other countries, the correct agency will be notified. These devices work world wide. With the GPS model, the device also sends up the GPS position every 10 to 15 minutes to help rescuers locate you quickly. The drawback with these devices is that they do require maintenance, testing and registration.

The key to all of this is that you need to carry a visual and audible signal with you at all times. There are a variety of different signal types depending on the conditions you expect to be in. If you want to see any of these signal devices let me know. Greg