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Best signalling equipment from the searchers point of view

Discussion in 'General Scuba Equipment Discussions' started by Navy OnStar, Dec 1, 2007.

  1. dannobee

    dannobee Instructor, Scuba

    # of Dives:
    Location: SF Bay Area
    2,480
    53
    48
    The giant OMS safety sausage/lift bag (9' 6") has a loop big enough to put your leg through-with your fin on. Gets you further out of the water and makes it stand straight up without holding it.
     
  2. HenrikBP

    HenrikBP Solo Diver

    # of Dives: 200 - 499
    Location: New Mexico
    5,163
    865
    113
    I have rigged a snap on my Zeagle SMB and figure I can snap the inflated SMB to one of the D-rings on my waist strap. If I snap it to the "scooter ring" it should keep the SMB upright in the water, fairly securely connected to me and maybe help me floating face up as well. Need to figure out a good way to mount a strobe on top of the SMB. That ought to increase visibility considerably.

    Henrik
     
  3. Navy OnStar

    Navy OnStar Angel Fish

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    Day or night, motion is great. It gets very tiring on a search and rescue. In the helicopter we (Navy) usually have 4 people and we are all responsible for a different sector around the aircraft. After spending a few hours searching you get wiped out from having to concentrate so hard looking for the proverbial needle in a haystack. My longest continous flight for a SAR was 13.1 hours and I didn't want to quit. Besides the time just flying the aircraft and scanning the endless ocean, the emotional toll of knowing that someone may die if you don't find them, just beats you down. After a few hours we get so tired we know we are losing effectiveness but we may be the only asset available to conduct the search so we continue.

    Another way to increase the efeectiveness of signals is motion. Even if you don't have any signaling devices, throwing water in the air can be effective.

    I like the glowstick on a string idea. I don't know how long you could twirl it but If you did it when you heard a helicopter/ship it would work. I wouldn't bother with the IR ones though. They are only used when you want the guys on NVG's to see you but nobody else. I think in this cae we want everyone to be able to see us.

    OnStar
     
  4. Navy OnStar

    Navy OnStar Angel Fish

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    If you don't mind carrying it, I say it's a great idea. The international distress frequency is 121.5 VHF. The U.S. also uses 243.0 UHF (exactly double the VHF frquency). Since you probably won't know your position without a GPS, I would broadcast on it every ten minutes until you hear someone reply. Then describe what you are wearing and have for signaling to make it easier for us to spot you. Knowing you are in handheld radio range would be a huge advantage and you could even vector the helicopter to you if you could see it. I would also ask anyone who answered if they had VHF direction finding equipment. If so then continually transmit and they should have a display that give a bearing to you. Then they just fly down the bearing until they see you.

    OnStar
     
  5. Walter

    Walter Instructor, Scuba

    18,583
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    Actually, any mirror is extremely easy to aim assuming you have two good hands. hold one hand in front of you with the V for victory (AKA peace) sign. Move your hand until the search plane or boat is visible at the base of the V. Use the mirror to reflect sunlight across your fingers and the boat. It's a better aiming method than using the hole in the center of a signalling mirror.

    Great thread! Lots of excellent information.
     
  6. PfcAJ

    PfcAJ Orca

    # of Dives: 5,000 - ∞
    Location: St Petersburg, Fl
    7,599
    6,309
    113
    Correct me if I'm wrong, I've been out of SAR for a while now. While 121.5 is the "distress freq" which EPIRBS and ELT's broadcast on (at least the older ones, I think the US is moving toward the 243.0 ones which include some additional information), handheld marine VHF radios broadcast on a different frequency range using a "channel" system. Ch16 is the one monitored by the USCG, and Ch68 is monitored by many boaters.

    I do not think it is possible to broadcast on 121.5 with a standard marine radio that you can pick up at West Marine or Boaters World. Just something to keep in mind.
     
  7. Navy OnStar

    Navy OnStar Angel Fish

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    You are correct. I guess I should have looked at the VHF radio listed. Military style radios (which are available) can be tuned to 121.5 and 243. Military aircraft are required to monitor Guard (243.0 and if able 121.5) so I was thinking from an aircraft point of view. Military and USCG helicopters can talk and receive on marine band VHF. USCG cutters and Navy ships usually monitor 16, and 9. I know we used 68 when I was on A Navy Ship but we didn't monitor it.

    Bottom line broadcast on 16 (Everyone monitors 16 in the U.S.) and 9, and if you can put in 121.5 into your radio then broadcast on that as well.

    Here's also a good one. Sea Marshall Personal Location Beacon (epirb)-Divers
     
  8. MConnelly2

    MConnelly2 Captain

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    Navy OnStar, you know what Motor Lifeboatmen call Navy helo crews? The search object!

    Good natured kidding aside, good topic to bring up. Thought I'd share a few thoughts from a Motor Lifeboat Heavy Weather Coxswain - sooner search object gets located, the more likely it is I'll be moored up in time for breakfast, so it is with an ulterior motive.

    Strobes - like Navy OnStar mentioned, these are your best friend at night. Inland Navigation Rules consider a "High intensity white light flashing at regular intervals of 50-70 flashes per minutes" to be a distress signal - but an SRU (Search and Rescue Unit, such as NavyOnStar's helo or my Motor Lifeboat) considers it to likely be the search object (that would be the guy floating in water that he doesn't want to be floating in), will see it, and check it out. On NVG's, or any night vision device, these strobes are like getting hit in the face with a snowball. (Navy, remember the SDU-5/E's?)

    EPIRBS - 121.5MHz is indeed the civil aviation 'guard' frequency, the tweetie version of the maritime world's channel 16. Some older EPIRBS only transmitted on 121.5, but these 'Class B' EPIRBS have not only been phased out, but are now illegal (yes, yes, I know, don't bother saying it, I agree). BUT, check this out - the newer EPIRBS, that transmit a composite signal via 406.025MHz to a satellite, back to Earth, solves for approximate position, et cetera, et cetera, ALSO transmit a low-power signal on 121.5MHz. This is because most Radio Direction Finders can DF a 121.5 signal, which means once we get close, either from the composite solution from the EPIRB or from old-school search planning (99% of the cases), if we pick up a 121.5 signal on the DF, we can steer right down it, right to you. A good Coxswain or Pilot is going to be looking for a 121.5 to run down on any search.

    SMB's - You know how hard it is to spot a person in the water? You're talking about something the size of half a cantaloupe on the surface. Not as easy as some might think. A big orange thing sticking out of the water would be soooo much easier to spot, especially if it's moving. Motion catches the attention of the human eye-brain-working-together-stuff WAAAAY easier than a simple incongruity in the neverending waterscape.

    I've never seen a diver carrying a handheld VHF, but if my search object came up for me on channel 16 while I was running a pattern looking for them - I'd fall out of my chair. And they'd be on my boat in very short order, and I'd be back in time for breakfast. Everyone would win. My goodness, that would be an easy one.

    -Mike
    (New to the diving thing, almost a decade at the SAR thing)
     
  9. weaponeer

    weaponeer Barracuda

    # of Dives: 200 - 499
    Location: Virginia
    349
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    I'd like to add my two cents worth on this thread.

    First, DAN sells an ID tag / signal mirror combo. Some of the cost goes right back to DAN. I bought one last year for myself and my wife, and it is always attached to our BCD. The tag shows personal info, including medical details good to know by rescuers if you are found unconscious, and contact info for next of kin. The mirror doesn't have a sighting hole, but it is a reflective mirror - better than nothing. Check the DAN website for details.

    I am a retired Navy Firecontrolman Senior Chief. I've lauched and shot at many a "killer tomato" during shipboard gunfire exercises. We attached to the top of the tomato a spherical RADAR reflector, and for long range shoots (16" battleship guns) we would inflate a weather balloon and hang the reflector between it and the tomato. The sphere was about 6" diameter. It lit up on search RADAR like nobody's business, and on Firecontrol RADAR we could track it past 20 miles. I've seen a variant of this sphere that folds flat, and when opened, provides corner reflectors (4 on each side) for good 360 degree, horizon to overhead, coverage. I've never seen one for sale, but it should be easy enough to make one.
     
  10. Charlie99

    Charlie99 Solo Diver

    # of Dives: 500 - 999
    Location: Silicon Valley, CA / New Bedford, MA / Kihei, Maui
    7,966
    158
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    Supposedly you can remove the reg from a tank, hold it a few inches under the surface and when you open the valve a big plume of spray shoots up.

    That's second hand info, not personally confirmed. Perhaps somebody else has tried this and has more info.
     

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