PLB Verses Hand held DSC radio

[JumbleDuck]

I would definitely go for the PLB. If you fall in around Britain you probably only have ten minutes of so for purposeful action and an hour, if you're lucky, of consciousness. That means that you won't be able to do anything useful with a VHF radio for very long at all. The PLB, on the other hand, will go on working until they pull your befuddled, unconscious or dead body from the water.

 

[bedouin]

The PLB, on the other hand, will go on working until they pull your befuddled, unconscious or dead body from the water.

I am not sure that is the case for all PLBs.

For a PLB to function the antenna needs to be deployed in the correct orientation - for some of the PLBs on the market is it not clear to me that it would be easy to maintain that deployment when in the water - even if fully conscious. Unfortunately I have not seen any tests or articles that discuss that.

Seems that most should be fine if correctly attached to your Lifejacket and you are floating on your back.

 

[prv]

I am not sure that is the case for all PLBs.

For a PLB to function the antenna needs to be deployed in the correct orientation - for some of the PLBs on the market is it not clear to me that it would be easy to maintain that deployment when in the water - even if fully conscious. Unfortunately I have not seen any tests or articles that discuss that.

Seems that most should be fine if correctly attached to your Lifejacket and you are floating on your back.

I was thinking the same thing. Most of the AIS beacons can be attached to a lifejacket, and they'll stay out of the water and correctly oriented, but I'm not aware of a PLB with the same feature. Most would probably sit reasonably snugly in the cleavage between the two halves of the lifejacket bladder, with the aerial pointing upwards, but you would have to put it there and ensure it stays in place (and a lanyard to avoid losing it would be pretty important).

I don't carry a PLB on my person, Ariam's is intended to be used from the liferaft or if in serious trouble on board out of VHF range, so the issue doesn't arise. But for the singlehanded MOB it would be good to have a PLB in the same packaging as the Kannad AIS beacon:

Pete

 

[bedouin]

I was thinking the same thing. Most of the AIS beacons can be attached to a lifejacket, and they'll stay out of the water and correctly oriented, but I'm not aware of a PLB with the same feature. Most would probably sit reasonably snugly in the cleavage between the two halves of the lifejacket bladder, with the aerial pointing upwards, but you would have to put it there and ensure it stays in place (and a lanyard to avoid losing it would be pretty important).

I don't carry a PLB on my person, Ariam's is intended to be used from the liferaft or if in serious trouble on board out of VHF range, so the issue doesn't arise. But for the singlehanded MOB it would be good to have a PLB in the same packaging as the Kannad AIS beacon:


Pete

I believe the good PLBs follow the same design as the AIS beacons - and in many cases (I think Kannard are like this) use the same packaging. I gather that one reason they don't combine the two into one package is that they are not allowed to.

But even for those that do that presupposes they are always carried correctly attached to the LJ. I don't do this myself, preferring to carry my (old) PLB separately in my oilies or on a belt round my waist.

 

[Strolls]

Most of the AIS beacons can be attached to a lifejacket, and they'll stay out of the water and correctly oriented, but I'm not aware of a PLB with the same feature. Most would probably sit reasonably snugly in the cleavage between the two halves of the lifejacket bladder, with the aerial pointing upwards, but you would have to put it there and ensure it stays in place (and a lanyard to avoid losing it would be pretty important).

GPS positions from one of the Cheeki Rafiki PLBs were still being received 16 hours after it was set off - surely it must have been operating autonomously and unassisted by that stage?

What was not clear to me, when I looked at the report yesterday, was whether it was operating at full efficiency.

After the initial signals, 24 alerts were received over about 17½ hours - was this all the transmissions made by the unit, or only those made when it happened to be bobbing to the surface?

This was a Kannad Safelink Solo PLB, similar in size and appearance to the McMurdo FastFind 220 owned by the other chap. Only a couple of signals, over 2½ hours, were received from this latter unit - I doubt it's worth speculating why the two PLBs performed differently.

 

[bedouin]

GPS positions from one of the Cheeki Rafiki PLBs were still being received 16 hours after it was set off - surely it must have been operating autonomously and unassisted by that stage?

What was not clear to me, when I looked at the report yesterday, was whether it was operating at full efficiency.

After the initial signals, 24 alerts were received over about 17½ hours - was this all the transmissions made by the unit, or only those made when it happened to be bobbing to the surface?

This was a Kannad Safelink Solo PLB, similar in size and appearance to the McMurdo FastFind 220 owned by the other chap. Only a couple of signals, over 2½ hours, were received from this latter unit - I doubt it's worth speculating why the two PLBs performed differently.

That incident was part of what got me thinking on this. From memory (I haven't read the report recently) the transmission from the PLBs was very patchy - only a couple of contacts in a period of hours. PLBs / EPIRBS transmit about once every 50seconds (again from memory) meaining you would expect to receive >1500 transmissions in the 24hour period the PLB should operate for. I took that to imply the PLBs were not operating "properly" and it seems to me poor deployment of the antenna is the most likely reason for that.

 

[JumbleDuck]

I am not sure that is the case for all PLBs.

For a PLB to function the antenna needs to be deployed in the correct orientation - for some of the PLBs on the market is it not clear to me that it would be easy to maintain that deployment when in the water - even if fully conscious. Unfortunately I have not seen any tests or articles that discuss that.

Good point. I was think of "working" as "transmitting" and forgot that it should really have been "transmitting in a way which means someone will hear it". Still, a VHF won't even have a go if the operator is out of it, so I suppose the question is whether a PLB is as bad or can be worn, as you suggest, in a way which means it can still have an effect.

I was planning to buy one this year, so this is clearly something I need to think about. Thanks!

 

[Caer Urfa]

Cheers gents

lots of constructive points and food for thought I guess the doors still open as to which is best !

I wonder when we will have a PLB that justs activates itself without some of the fiddly bits especially having to deploy an aerial.

As to which PLB is best I suppose you pays ya money and takes ya pick, problem is the best recommendations can best be supplied by those
that have fell in and had to use one.

Mike

 

[Neil]

I SH most of the time and I have a PLB inside the LJ, so that when it inflates, the PLB is in position - I just have to release the aerial and press the panic button. However, I always carry a HH VHF clipped to the LJ. My thinking is that if I can be heard on the VHF, I'll get a quicker response but if there is no immediate reply, the PLB is activated immediately.

 

[Allan]

I had a conversation a few months ago with someone who insisted that DSC works in exactly the same way as PLBs. He refused to accept that DSC does not use satellites. As said above, a HH DSC unit, at sea level would struggle to reach more than a couple of miles.
The first thing I pick up is my PLB.
Allan

 

[prv]

I believe the good PLBs follow the same design as the AIS beacons

It would be logical, but I don't know of any that do. The Kannad SafeLink Solo (PLB) certainly doesn't use the same enclosure as the Kannad R10 (AIS), and doesn't AFAIK have any sort of mounting facility beyond a basic lanyard loop on the bottom.

Pete

 

[prv]

I SH most of the time and I have a PLB inside the LJ, so that when it inflates, the PLB is in position - I just have to release the aerial and press the panic button.

That's very interesting - what model is it? How does it attach to the lifejacket?

Pete

 

[Twister_Ken]

As said above, a HH DSC unit, at sea level would struggle to reach more than a couple of miles.

Allan

In case anyone from PBO is reading, handhelds have been tested several times over the years but not, AFAIK, from a person in the water. That would make interesting reading - certainly more so than on article on how to use a hammer.

 

[prv]

I had a conversation a few months ago with someone who insisted that DSC works in exactly the same way as PLBs. He refused to accept that DSC does not use satellites.

I was once on a sailing ship well out into the Atlantic, and an old guy amongst the voyage crew was complaining that his phone (an ordinary mobile) wasn't working. He was insistent that it should, "because satellites orbit the whole world", and was very reluctant to believe that mobile phones use land-based antennas.

Pete

 

[rogerthebodger]

There has been talk about VHF range with the HH at sea level but there is a formula for calculating line of site based on the height of the 2 heights (sender and receiver)

With my aerial on my boat being 15 metres above sea level the range in in the order of 10 miles. CG and commercial ships would have an aerial much higher thus a greater range even with the HH at sea level.

A DSC emergency call only means pressing the Big Red Button and then the transmit button as pressing BRS automatically selects Ch 16 and both transmitting radio and all the receiving radios.

 

[bedouin]

There has been talk about VHF range with the HH at sea level but there is a formula for calculating line of site based on the height of the 2 heights (sender and receiver)

With my aerial on my boat being 15 metres above sea level the range in in the order of 10 miles. CG and commercial ships would have an aerial much higher thus a greater range even with the HH at sea level.

A DSC emergency call only means pressing the Big Red Button and then the transmit button as pressing BRS automatically selects Ch 16 and both transmitting radio and all the receiving radios.

Think of yourself being in the sea with any form of swell running.

How far away do you reckon you could see a ship (i.e. continuously not intermittently). Even from the deck of my boat I don't expect to have a range of more than 2-3 miles with the HH

 

[Neil]

That's very interesting - what model is it? How does it attach to the lifejacket?

Pete

It's an ACR of some sort. The LJ has a pocket/ flap on the upper surface of the bladder.

 

[prv]

It's an ACR of some sort. The LJ has a pocket/ flap on the upper surface of the bladder.

Cheers, that's interesting. I'm not especially familiar with the ACR units, but that one looks like there's been at least a passing thought to lifejacket mounting with the loops top and bottom. But it's the built-in pouch on the lifejacket bladder that really makes the idea work, by the sounds of it?

Pete

 

[Neil]

Yes, the LJ is a ErgoFit 290N Extreme. Maybe a bit OTT for my sailing but it was on offer at the time

The PLB is an ACR ResQLink+™ - it has a velcro strap running between the top and bottom loops so it's easy to attach to things

 

[Dockhead]

There was a case last year when an experienced singlehanded sailor ended up in the water alongside his boat. He had both Vhf and Plb but by the time he realised he could not save himself his hands were too cold to operate his devices!

Www.solocoastalsailing.co.uk

Terrifying.

The best MOB device for non-remote waters is an AIS MOB beacon. That alerts vessels close enough to help you and requires little to nothing (if it's rigged to trigger with your life jacket) to operate it. It does not require a voice conversation to explain the nature of the distress as DSC does.

PLB is the best device for remote waters, but you have to operate it -- you have to deploy the antenna, trigger it, and hold it up above the water with the antenna directed in the right way. Could be hard in a storm, cold hands, etc.

VHF handheld is great because you can talk to someone, but very short range, and you have to operate it. I don't carry one of these on my person because limited usefulness and present models are very bulky. I would start carrying one if they ever make a really compact one for emergency use, with a long life single use lithium battery.

I do keep both a PLB and an AIS MOB beacon lanyarded in my life jacket.