Visit our Popular Forums

goagoa · 27-01-2009, 02:14

Me and my husband on june start cruising round the world. Iwant to buy new EPIRB as cheap as possible, but I dont know which is right and the most suitable for us. Boat is steel 12m/4m.
What is the difference between internal and external GPS? Which one is better?

Bill_E · 27-01-2009, 16:26

I'm not really expert in EPIRBs but I recently did a bunch of research prior to purchasing one for our boat. First of all make sure that you get a 406 MHz one. Those are what you will mostly find, the older 121.5 MHz ones will not be used in less than a month.

My opinion is that you want to keep it simple. To me, that meant getting one with an internal GPS. Of course a GPS is not really needed because the satellites can triangulate on your signal and get pretty close. But I felt that it was worth the added resolution to have a GPS included. I read that the US Naval Academy did an experiment and found that the location of the EPIRB was found within 15 minutes. One without a GPS has an accuracy of location of about 1.5 NM and one with a GPS is much closer, perhaps 50 meters.
I hope this helps.

Bill

Captn_Black · 27-01-2009, 17:31

Hope this helps - Epirb - Electronics | Marine Super Store
They relatively cheap on this site, and they go into some detail about what you get for your money...

Thanna5 · 27-01-2009, 18:49

Try Ebay,

Many vendors advertise buy it now prices cheaper than the do in their store.Often good deals for NIB items as well. I've bought 2 and had no problems

highseas · 27-01-2009, 19:14

I bought the ACR Microfix 406 PLB with internal GPS,small enough to carry on my person.It has the 30 hr. battery.I checked with the registrar,no guarantee anyone will be monitoring old frequency,but if they do they will still investigate,as many people still only have old ones.I have both ,which I would activate need be.

MarkJ · 28-01-2009, 01:54

Get the little ACR with internal GPS. Ours is 24 hours and if it hasnt transmitted the lat and lon by then you'll probably be dead anyway.
The small ones are half the price and just as good as the big ones

The external GPS means you have to plug the epirb into your GPS with an nmea cable while you are sinking. I dont think thats likely as I will be kissing my a$$ goodbye

Captn_Black · 28-01-2009, 06:36

I would have a little problem with the externally mounted auto transmitting ones, as I may not be ready to abandon ship 'just' because I capsize...

MidLandOne · 28-01-2009, 18:29

I would personally get an ACR EPIRB with integrated GPS. We have had an ACR for 13 years now (I assume it would have worked if ever needed

- and being ACR it will be scrapped at next service under their aging policy) and they also seem to be the favourite choice of commercial users.

I would recommend that you get one that turns itself on when placed into water (many of the recent cheap EPIRBs have to be manually turned on - but without my double checking, as I recall it all ACR models do turn themselves on in water). This means if you take it with you to a raft or you drop it before tethering it on its leash it will automatically operate even if you cannot recover it. Seems to me easy to remember in an emergency that the dang thing will turn itself on if you have to leave the boat when you tether it to the raft with its lanyard (EPIRB's work best floating in the water). You can, of course, choose to manually turn it on if wished eg if the boat is not to be evacuated.

Note, I am NOT referring here to the auto release ones that live in a holder above deck and float free automatically when submerged (generally at around 4m). Like Captain Jaz I am not a fan of the auto release EPIRBs (known as CAT I) on sailboats as there is just too much for them to foul on (same with auto release liferafts).

I would stay away from the recomendation that has been made to get a PLB as the primary EPIRB for a boat. They are not guaranteed (nor even expected) to float so if you drop it you are likely to wave it goodbye as it goes to the bottom. They also have technical deficiencies in comparison in way of at least shorter transmission time and poorer radiated signal efficiency. Also, in some countries (the UK for instance) PLB's cannot be registered to either a person or a boat so for those the veracity of an alert by checking with registered contacts can be determined.

MarkJ - the EPIRB's that connect to an external GPS for the fix are left connected all the time until the time of distress - you do not connect them to the GPS when the distress occurs (well not any I know of, but if there are I would avoid them like the plague

). This means that they have a fix immediately available to transmit whereas a conventional integrated GPS type has to go through the process of aquiring satellites and calculating the fix before it can transmit a position. So the external GPS type is quicker, not slower. Wotname, I believe it was, gave some information regarding the actual times involved in an earlier thread if interested.

In the end, for oceanic cruising where rescues take some time to arrange, the time in getting a fix as between the GPS and non GPS types is of little relevance in my view. The accuracy of a GPS fix may be of some advantage. If you have to forego something due to budget, go without the GPS.

**Wotname** · 29-01-2009, 20:23

IIRC, the internal GPS has to provide a fix within 2 minutes of a cold start but I haven't time now to recheck the Cospas specs.

I agree with Mid.1 that if budget requires it, then drop the internal GPS option and while I agree with his premise of the time taken for a fix when oceanic cruising is not relevant, I suggest that the additionial positional accuracy (of the GPS option) is highly relevant especially when mid ocean.

1. A accurate fix is ALWAYS better a less accurate one.
2. When further away from the shore, there is always less time available for search aircraft (or ships) to spend in the search area; therefore a highly accurate fix is much better.
3. As most (all ?) 406 beacons stop transmitting after 24 hours and a physical sighting of the contact may take greater than 24 hours, then the final estimated position of the conatct can only be estimated from the previous 24 hours of drift. If the beacon is transmitting GPS co-ordinates, then the drift can be more accuratly established.

FWIW, the 121.5 transmitter of a PLB is only 24 hours while that of a EPIRB is 48 hours (remembering the 406 transmitter is switched off after 24 hours).

la5zo · 07-02-2009, 08:54

Why save on safety ? Get this one:
ACR GlobalFix 406 MHz EPIRB with GPS - BoatersWorld.com
Built-in GPS for best accuracy, strobe-light, self-deploys if boat sinks before you can get to the EPIRB and 48 hrs. battery.

Geir
S/Y Destiny

**Jim Cate** · 07-02-2009, 09:06

I wonder how large a solar panel would have to be to keep an EPIRB running a bit longer than the 24-48 hours providedby the internal battery? Even if it only would work during daylight (not enough output to charge a battery for night time usage), it would certainly expand the possibilities for way offshore search efforts.

Cheers,

Jim and Ann s/v Insatiable II

la5zo · 07-02-2009, 09:19

Dunno if u can get EPIRBS that can be run from external batteries/solars.
Dont think you will need more than 48 hrs. if you have the GPS version.
With this version you might save on batteries turning the EPIRB off after a few hours
and back on again. As the beacon send out you ID and coordinates the rescue effort can be concentrated at your position without having to do a lengthy search before the rescue. If you eventually should run out of batteries they will start search at latest given position based on weather/current offset.

Geir
S/Y Destiny

dacust · 07-02-2009, 12:09

With no GPS at all, the beacon can report a position within 1.5nm (from another post, not my own knowlege). In a stormy ocean, that is a long, long way, but still good enough to narrow the search down to where they will likely find you.

With an external GPS, it can report the location of your boat within a few meters, but if you have to abandon ship, the location if your life boat an hour later will only be reported within 1.5nm.

An internal GPS will continue to report the location of your lifeboat within a few meters.

So, no GPS is better than nothing.

An external GPS will report an accurate position if your emergency doesn't require you to leave your boat and the GPS remains connected (and powered).

But the internal GPS will always report an accurate position.

-dan