Personal MOB Devices

[Dazzler]

Recent discussion in the thread: “Fleet info - AIS Transceiver” started to drift off topic to a discussion of Personal MOB Devices such as VHF-DSC-GPS radios, PLB’s and AIS-SART (McMurdo Smartfind S20 SS AIS). So as to help keep that thread on topic, I’ve started a new thread for discussion of personal MOB devices.

So, what is your experience? What are the pros and cons of such devices? What's best for near shore (Gulf of the Farallones) races where other vessels (other racers as well as commercial vessels, fishing boats, pilot boat and USCG) might be the first responders. Is a different solution best for offshore races? When is a PLB a good choice?

We now have the requirement for portable VHF-DSC-GPS radios, but most units are a bit large to attach to your PFD and obviously, if you end up in the water without it you are SOL. How are you addressing that issue?

Tom
DAZZLER
CLOUD

 

[todd22123]

I think this side of the Farallon Islands, if one is choosing between wearing a PLB or wearing a Handheld VHF with DSC, the best is the Handheld VHF with DSC. I believe this was discussed at the 1/2 day Safety and Sea course that is required for entry into some of the local ocean races.

The radio can fit into the stretchy pocket of a Spinlock Inflatable Deckvest. It is a bit bulky, though.

Anecdotally, from one of the participants in the SAS Seminar, pushing the Distress button on the VHF with DSC gets immediate response. The ability to, in many cases, communicate with the person who pushed the button is considered an advantage, and this can help the responding Coast Guard determine the best response.

Also, others near the Distress can theoretically hear about this as well.

At some point, estimated by me, such as beyond the Farallon Islands, the VHF would not reliably signal the land based antenna, then the PLB is better.

This is just based on what I have read and what I recall from the Safety at Sea Seminar. I, myself, have never pushed the button on either, and I carry the Handheld DSC/VHF when sailing mostly in the bay.

You probably read about a recent incident in SF Bay where a Singlehander on an Express 27 went over, was tethered, was unable to reboard, and this man found his VHF to be very useful. I believe he just used it to call for assistance, and did not push a DSC Distress, although I am not sure of that.

Todd

Todd

 

[JAMcDonald]

I'm starting to investigate AIS-SART devices for crewed MOB as well. The issue appears to be that many multifunction displays do not interpret AIS SART message 14 and display an appropriate alert signal. Some do, for example the Standard Horizon 2200 VHF/AIS/GPS receiver. I'm trying to determine if the NKE Multigraphic display, my principal nav instrument interprets AIS SART messages appropriately. The em-trak B100 AIS transceiver receives the appropriate message, but your display unit must be coded to respond appropriately.

Bottom line is either a AIS-SART or DSC for self-rescue by a vessel carrying appropriate receiver/display. DSC is more likely to be received, as many smaller fishing vessels I've encountered don't have AIS transceivers. They may well have receivers, but no way to tell. VHF is near universal, although it doesn't appear anecdotally that all vessels monitor 16. If DSC equipped, the alert is automatically received. The DSC portable VHF's have the disadvantage of size and requiring frequent charging, whereas the AIS-SART devices can be placed on a PFD and forgotten.

 

[pogen]

as I said on the other thread...

I bought 2 of the Smartfind-type devices [AIS-SART] before PacCup for over $300 each, and found on testing that no plotters or radios on the present market can properly process their signal to generate an alarm. When I called the USCG rescue center to tell them I was testing this type of device, they had no idea what I was talking about. So, a more generic device like the Nautilus or a HH VHF-DSC-GPS radio kept on your person is the best bet for personal MOB.

It may be that the latest and greatest from Standard Horizon or other plotter/radio makers can interperate the message and the MMSI number, which for emergency beacons always starts with '9'. However, unless you are planning on getting rescued by your own boat, and you know you have the gear set up right, what will happen is that other ships will see you as an AIS target, but they wont realize you are in trouble -- and if they don't look at the display they wont notice you at all.

 

[JAMcDonald]

Copy. AIS-SART devices are not so useful for singlehanding. The manufacturers of AIS-SARTs should publish a list of compatible displays. I'm only considering self-rescue by crewed vessel where, if an appropriate display is available they should serve well. For singlehanding I carry a DSC waterproof VHF and a 406 PLB. The NKE AP system has MOB function for solo where it steers the vessel into the apparent wind, and with crewed setting an alert provides a dead reckoning position to navigate to the position where the alert was activated - not as useful as DSC or AIS.

If you want to sell or rent your AIS-SARTs I might be interested for the Pac Cup.

 

[K38Bob]

I think this side of the Farallon Islands, if one is choosing between wearing a PLB or wearing a Handheld VHF with DSC, the best is the Handheld VHF with DSC. I believe this was discussed at the 1/2 day Safety and Sea course that is required for entry into some of the local ocean races.

The radio can fit into the stretchy pocket of a Spinlock Inflatable Deckvest. It is a bit bulky, though.

Anecdotally, from one of the participants in the SAS Seminar, pushing the Distress button on the VHF with DSC gets immediate response. The ability to, in many cases, communicate with the person who pushed the button is considered an advantage, and this can help the responding Coast Guard determine the best response.

Also, others near the Distress can theoretically hear about this as well.

At some point, estimated by me, such as beyond the Farallon Islands, the VHF would not reliably signal the land based antenna, then the PLB is better.

This is just based on what I have read and what I recall from the Safety at Sea Seminar. I, myself, have never pushed the button on either, and I carry the Handheld DSC/VHF when sailing mostly in the bay.

You probably read about a recent incident in SF Bay where a Singlehander on an Express 27 went over, was tethered, was unable to reboard, and this man found his VHF to be very useful. I believe he just used it to call for assistance, and did not push a DSC Distress, although I am not sure of that.

Todd

Todd

You might want to talk to Jim Q who attended this and the awards event where test results were provided.
http://www.pressure-drop.us/forums/content.php?4288-DSC-Calling-Who-s-Gonna-Answer

In this live fire test, a distress boat at the OYC guest dock pushed the big red button. The CG got the signal and location so did the pseudo race comm w the chartplotter courtesy of Andy. And the "fleet" brought there handhelds

This screen shot shows the Lat/long of the distress boat

This is the magic- it shows range 0.07 nm and bearing 86 degrees of the distress relative to the fleet racer handheld in OYC dining room.
Also graphically...see the black dot due east. So one button serves as MOB for your boat to get you, and alerts the fleet and the cg. Apparently it will daisy chain along the fleet to the cg if you are out of range of the CG. Plus you have voice communication

Here's OYC.. the guest dock is the long dock about 0.07 nm to to east
http://goo.gl/maps/eNaza

Powerful tool in its range