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Old 08-05-2012, 09:00   #16
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That probably would not translate directly into the same time difference to rescue. Even with a gps position the SAR authorities would make the contact calls before dispatching a unit. I can't remember if it was this forum or SSCA but a Coastie involved with this kind of thing explained that its usually about 30 minutes of this type of overhead before units are actually dispatched. There is still a time and precision of position advantage to GPIRB vs EPIRB but not so much as it would seem at first blush.

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Old 08-05-2012, 10:29   #17
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Re: EPIRB

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Originally Posted by SoonerSailor View Post
That probably would not translate directly into the same time difference to rescue. Even with a gps position the SAR authorities would make the contact calls before dispatching a unit. I can't remember if it was this forum or SSCA but a Coastie involved with this kind of thing explained that its usually about 30 minutes of this type of overhead before units are actually dispatched. There is still a time and precision of position advantage to GPIRB vs EPIRB but not so much as it would seem at first blush.

Chip
Agreed, but any reduction in time is a very good thing and another big reduction in time (with GPIRB) is that the SAR asset goes straight to the correct location and not into a homing search.
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Old 08-05-2012, 13:21   #18
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Here is a suggestion from out of the blue.

Why not use a device which you can truly test everyday in the real world, a device which you can connect to the authorities and the Internet, a device which can have the standard offf-the-shelf batteries changed by you. 48 hours?!?? Put spare AAA batteries in your ditch bag and send out signals for a week!

Which device is this?
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Old 08-05-2012, 14:43   #19
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Re: EPIRB

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Here is a suggestion from out of the blue.

Why not use a device which you can truly test everyday in the real world, a device which you can connect to the authorities and the Internet, a device which can have the standard offf-the-shelf batteries changed by you. 48 hours?!?? Put spare AAA batteries in your ditch bag and send out signals for a week!

Which device is this?
Iridium? (other than the AAA batteries). The latest model has a built-in GPS, and is moderately water-resistant, but I don't think I would trust it to save my life when I am floating in my PFD. EPIRBS are designed as they are for a reason. If I'm still aboard my boat, or in the life raft, I'm definitely going to be using the satphone as well as the EPIRB should the need arise.
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Old 08-05-2012, 18:03   #20
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I guess you are right to a certain extent about the Iridium, but I was actually thinking about a SPOT device.

If we ever hit the SOS button instead of the OK button, not only will the authorities get the message but all our sailing mates will get it via email, along with all facebook mates via a status update.
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Old 08-05-2012, 19:24   #21
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Re: EPIRB

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Exactly plus of course, raising the alarm in the first place with not much more than a untrained flick of a switch!

Looking at some more numbers an EPRIB without an embedded GPS may take a couple of hours for a position to be determined and may have an error of 20 Km (12 miles). That gives a search area of say 1,200 sq Km (450 sq miles).

However an EPRIB with an embedded GPS will give a position fix within 2 minutes with an worst case accuracy of 100 m giving a search area of 0.03 sq Km and more likely will be accurate to 15 m giving virtually no search area at all.

I personally would much prefer to see an SAR helicopter fly in a nice straight line towards me and hover directly above rather than see one in the far distance conducting a grid (homing) search across an area of 1,200 sq Kms.

YMMV
Not true...even without a GPS burst an Epirb will usually give a rough posit within the hour...and the posit is usually fine tuned within 5 miles within 2 hrs. The Launch of a helo usually takes 20-30 minutes anyway and the flight time is another say 30 on average...so within that first hour...they have a close enough spot that they will find you in no time if your 121.5 homing freq is still active.

That's all assuming you are even in the radius of an alert helo crew....

The system was set up to work just fine withiut a GPS in the EPIRB...but the cost has come down so much these days...nuts not to have a GPIRB.

Right from their website..my info was "experienced info"...

Two important considerations
First, a GPS-equipped beacon only works when the receiver has a clear view of the sky in order to permit the receiver to self-locate. Often times, conditions do not permit this which may either distort the positional accuracy or negate it altogether. Because of this, the Cospas-Sarsat System relies upon the Doppler locating effect as the primary means for locating a beacon. This process is able to overcome the limitations of a GPS unit and still generate a fairly accurate location…within a mile for positional accuracy. Secondly, the GEOSAR component only works if the beacon is registered with NOAA. Without registration, the RCCs are unable to react as quickly…and ultimately this may delay a SAR response should you be in an emergency. If you have a 406 MHz beacon and have not registered it, please do so by clicking here to access the National 406 MHz Registration Database.
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Old 08-05-2012, 19:43   #22
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Re: EPIRB

My wife pulled people out of the water when she was in the Coast Guard. When it's shitty out it's really hard to see people in the water even when you're close. Even with an exact GPS position it's no cake walk. Throw an old hat or a fender overboard sometime when it's blowing 25 and sail away for say 1 minute without looking, turn around and see if you can find it.
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Old 08-05-2012, 20:06   #23
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Re: EPIRB

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Curious, when the EPIRB is triggered. SAR get's an alert, the process then is put in place to come find me. Now, why do you need the EPIRB any longer. SAR is smart enough to know, if they cant get to me in a matter of hours that my position is going to change. Humor me. Don't they calculate the current and wind speeds and setout for my location based on that? Seems to me that that would be the case. And yes, the EPIRB being fully functioning would make it easier for them I guess. I plan on having a handheld radio with me to communicate with

In the Hobart tragedy it took 12 to 16 hours to get to some boats. There is a hell of a lot of drift in that time. They dont know if you're drifting or under a jury rig, trying to make way? There are a lot of variables and calculating drift is not an exact science.

The old 121.5 MHz and 243 MHz really only ever gave an area of location and nothing too specific. But made a great starting point,. The 406 can not predict your drift-leeway etc. If you and four other boats are being blown out to sea. You may have some time to wait depending on the amount of rescue vessels and choppers available. Also depending on the depth of emergency. If the other boats are sinking faster, you may just be last on the list.

Never rely on a hand held as the main source of communication if going offshore.They don't have the same power output as a ships station. Hand helds are 5watt . A standard ships station is 25 watts.

If you would like to see a case were time, epirbs, commincation, weather and men all battle each other, this docco will give you a real insight into good epirbs and com's.
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Old 08-05-2012, 22:48   #24
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Re: EPIRB

Gee, I wonder what happened? I'll stay away from the Tasman sea thank you. Have a friend from Hobarth. He's sailed there in 30-40 foot seas. Not a good place to be in summer or winter.
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Old 08-05-2012, 23:50   #25
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Re: EPIRB

The Tasman is known to be a bit nasty, but tolerable. Bass strait (lower west Bass Strait) is the really tough part. Having done it once, in similar conditions to your friend, I only intend sailing north from now on.

Btw, that vid is the first in the series. There are links to the rest, should you care to watch them, on the right hand of the YT page
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Old 09-05-2012, 03:49   #26
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Re: EPIRB

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Originally Posted by sww914 View Post
My wife pulled people out of the water when she was in the Coast Guard. When it's shitty out it's really hard to see people in the water even when you're close. Even with an exact GPS position it's no cake walk. Throw an old hat or a fender overboard sometime when it's blowing 25 and sail away for say 1 minute without looking, turn around and see if you can find it.
Exactly...that why you have a MOB/recue/survival plan and pieces of gear like an EPIRB are PART of a survival/rescue system.

Relying on only one piece or several unrelated pieces of gear may never get you rescued. You have to understand the dynamics of survival at your end and the dynamics of the rescue from the rescuers end....tying the two together at as many points of contact are the events that will likely get you rescued.
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Old 09-05-2012, 21:01   #27
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Re: EPIRB

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Exactly...that why you have a MOB/recue/survival plan and pieces of gear like an EPIRB are PART of a survival/rescue system.

Relying on only one piece or several unrelated pieces of gear may never get you rescued. You have to understand the dynamics of survival at your end and the dynamics of the rescue from the rescuers end....tying the two together at as many points of contact are the events that will likely get you rescued.

Exactly, exactly. There are a lot of experience boaters out there who still think that it only takes 10 minutes to be rescued. In some cases it can be days. The variables of travel time, weather, sea state and the nature of the emergency provide little less than organised chaos, rather than organised rescue. (no offence to the rescue people- but I am certain they know exactly what I mean.)
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Old 10-05-2012, 03:28   #28
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Re: EPIRB

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Exactly, exactly. There are a lot of experience boaters out there who still think that it only takes 10 minutes to be rescued. In some cases it can be days. The variables of travel time, weather, sea state and the nature of the emergency provide little less than organised chaos, rather than organised rescue. (no offence to the rescue people- but I am certain they know exactly what I mean.)
yep..glad some people recognize the nature of the beast!
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Old 10-05-2012, 03:39   #29
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Re: EPIRB

When we capsized our cat we had our Epirb. The spotter plane took over an hour to locate us we could see it built they could not see us. We were still tethered to the upturn hull In a life raft. It's a big sea out there and you are just a dot in the ocean
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Old 10-05-2012, 04:36   #30
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Re: EPIRB

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Not true...even without a GPS burst an Epirb will usually give a rough posit within the hour...and the posit is usually fine tuned within 5 miles within 2 hrs. The Launch of a helo usually takes 20-30 minutes anyway and the flight time is another say 30 on average...so within that first hour...they have a close enough spot that they will find you in no time if your 121.5 homing freq is still active.

That's all assuming you are even in the radius of an alert helo crew....

The system was set up to work just fine withiut a GPS in the EPIRB...but the cost has come down so much these days...nuts not to have a GPIRB.

Right from their website..my info was "experienced info"...

Two important considerations
First, a GPS-equipped beacon only works when the receiver has a clear view of the sky in order to permit the receiver to self-locate. Often times, conditions do not permit this which may either distort the positional accuracy or negate it altogether. Because of this, the Cospas-Sarsat System relies upon the Doppler locating effect as the primary means for locating a beacon. This process is able to overcome the limitations of a GPS unit and still generate a fairly accurate location…within a mile for positional accuracy. .......
Which website was this from; it differs from significant other EPRIB sites. I don't have time tonight to link other sits but I can later!

I think you find that most if not all marine applications will have a clear view of the sky for the GPS component when activated!
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