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Freediver / Scuba Diver EPIRB, help !!

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.


Mr. Long Post
Apr 22, 2002
Gentlemen & Ladies,

I have been looking for a radio transmitter based unit for freedivers and scubadivers to use when trying to call a boat when we drifted way too far.

I been surfing for ages and none has the spec I required. I even tried making myself one but size wise, it is big and bulky.

The closest thing available in the market is ACR EPIRB which ACR also sells the handheld Radio Direction Finder ( RDF ) unit. Sea Marshall of UK has a similiar unit, transmitter only. Both unit can go to 200 feet depth rating. Both are 121.5 Mhz unit.

I am sure many here are familiar on how EPIRB works. The problem I see with 121.5 Mhz is that :

01. By 2006 the US Coast Guard COPAS/SARSAT will stop monitoring this frequency.

02. It has a 99% false alarm, this means 1% survival rate to us users.

03. The position accuracy is the worst. The time it will take a SAR HQ in USA to receive the signal can be half a day or something depending where the satellites are when u activate the unit.

No pleasure craft/boat carry 121.5 Mhz radio receiver or RDF, this is international aviation distress frequency and only government/navy/US Coast Guard boats carry this, perhaps not all.

What I am looking for is a 200 feet depth rated transmitter which send out signal on the Marine VHF frequency. This kind of EPIRB was available long time ago but stop being used/produced according to SAR www.

My reasoning is simple. If we dive and get drifted and activate a 121.5 Mhz EPIRB, our dive boat doesn't know. If the captain declare us as a lost diver, it will be some hours, at least he will do a search first. The more hours we drift, the further away we got lost. The next action will be to call the US Coast Guard for help. Not only many countries are not as rich and well equip as the US and Euro countries Coast Guard, why burden the authority if we can avoid it. Rescue success from 121.5 Mhz is a sad case because daily SAR HQ receive hundreds of false alarm.

If say someone makes a 200 feet depth rated Marine VHF transreceiver, or make a compact housing 200 feet housing for the new 3 feet rated summersible Standard Communication mini VHF ( model I forgot ..460HX something ), we could call our boat immediately as when we drift too far. Summersible units can be used with wet hands and gloves and will survive 3 feet submersion for 30 minutes.

In many cases we can see the dive boat when we surfaced but the boat could not see us (mainly scuba divers ) . We also can tell our position to the boat by the available land mark. The boat captain also can tell that he is going the wrong way as the radio signal from us get weaker. We can also hail on channel 16 to other possible boats in the vicinity. If say a dive spot has a 2 knot current, technicaly we can not drift further than 2.2 miles an hour. The first 600 yards / 550 meters is distance we can not be seen from a boat without binoculars, much less if the water is choppy.

Smoke kit is another item to carry but if situation is very windy it is not effective. Parachute flares is not so reliable, not only the burn time is short, the boat or crew might not be looking at our direction. These two fire-risk item are not allowed as baggage on airlines.

What I have now is a marine VHF which I dismantled into pieces and keep in in a Underwater Kinetic 1200 torchlight. I use the torch housing as a proven waterproof casing. Since the VHF is not summersible, everytime I turned on the torch switch, it activates the VHF which is already pre-pressed (transmit ) and it emits an audio signal on my choosen channel produced by a 10 second voice recording chip. If I ever get stranded on dry land, I can undo the torch and use the regular transmit key, microphone and access the key pad for channel change. My own make is not very robust, wires and stuff criss cross everywhere inside, quite fragile. In fact it is not an original marine VHF, it is a 144 Mhz unit which I get someone to break the frequency limit switch, thus it can go to marine VHF frequency. I use this set because in my country 144 Mhz is popular among radio chit-chat community ( ham ??? ), so I want more possibility of a rescue.

I have looked at Sea Otter dry box and they make only a 100 feet rated, since I am a scuba guy, it is not good enough. My other option is an Ikelite disposable U/W camera housing, which might fit in the new small size VHFs.

Since this board has so many people from all kinds of background, I wish to get some good idea.

The ACR EPIRB and its RDF is the closest thing there is I seen but that means only a boat carrying the RDF is a possible rescuer. If I can transmit on channel 16, my chance of survival will be much higher.

Any ideas or info guys ??????????

OMS has one advertised in their catalog, at least they did at one time. I remember seeing pictures of Billy Deans with one strapped to the manifold on his doubles. I think that the OMS one even has a small hand held receiver.

I don't dive with one but I do (scuba) dive with a signal sausage, whistle, signal mirror, and a deco bag with my name on it.
Thanks Jon,

I have all available surface signaling except smoke kit or flare kit, I am a scuba guy too. Will look into OMS. Just like to be extra careful caused I driften far once and had read a 24 hr and 36 hr drifted scuba divers in my area. Thanks again.
Originally posted by Iyadiver
Just like to be extra careful caused I driften far once and had read a 24 hr and 36 hr drifted scuba divers in my area. Thanks again.

...which, after meeting Iyadiver, I know he survived! I think it was because he always keeps a pack of smokes and a mickey of Chivas strapped to his B.C. ;)
Cheers Iya,
Erik Y.
For the safety minded concerned about getting separated from the boat, I highly recommend taking a powerful dive light - even in the day time. Twice I have been separated from the boat in strong currents. Once the distance was about a mile. Because I always carry my light, the boat could find us easily.
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