I'm on mobile right now, and doing some research. I'm going to get a new VHF, and I'm thinking of getting one with AIS. To that end, I see that some of them also have built in MOB sensors. Are those worth it? Is it worth it to have it attached to the VHF? I'm not even sure if the VHF is supposed to stay on for longer passages. I mean, I imagine yes, but I'd guess that in reality, no.
What are your thoughts? I can probably do without one, but in case it is, might as well make that decision now when I have money and easy shipping, right?
Jordan,
The first decision would be a fixed mount radio or handheld. Each (like everything else) have its advantages.
Fixed
Known location in an emergency
Higher wattage output - government regulations
Longer reach - masthead antenna
More available features
Handheld
Portability to the event
Take it with you during abandon ship
Not dependent upon ships power (or lack thereof)
Because of the above you should have both. Both should have DSC (digital selective calling). Both should be a quality unit if you are going to depend upon them for saving your life or someone elses. Both should be operational when leaving the hook or dock.
As far as MOB capability there are several forms. Fixed VHF units that are equipped with smart remote mics often have the ability to trigger a MOB right from the cockpit. In many cases it is the DSC system that provides the alert. Others communicate with your other navigation equipment and alert the system of a MOB situation marking it on your chart plotter. Others communicate directly with MOB transmitters sounding an alert when the transmitter travels out of range. That system works like a wireless invisible fence system for dogs. When the dog wearing the collar travels outside of the transmit/receive range the collar zaps the dog. In this case the boats base station alerts occupants of the boat and also sends the information to your navigation equipment to "mark the spot" and even sends a DSC alert.
I would recommend that one has a MOB pole onboard that can be deployed by the remaining occupant on the boat during an emergency. The MOB pole provides a visual place marker to locate the person in the water. It should be equipped with a strobe and a MOB transmitter. All of this provides time for the boat to be turned around and any hope to relocate the lost crew. Three of my kids just went through a MOB situation while racing in brisk conditions in a Wednesday night beer can race. The individual that went swimming stumbled during a tack and took a header over the lifelines. Because everybody was busy and focused on their tasks no one noticed he was gone until someone happened to look up and wondered what that thing floating was. The boat was traveling at around 14 feet per second so by the time the MOB surfaced they were over a boat length away. In the seconds it to to recognize he was gone, hundreds and hundreds of feet were beneath the keel. The time it took to douse sails, start the engine and turn the boat added additional distance. At no point after the turn could the person in the water be seen. The chances that their boat could have located the person was slim. They were far right boat on the uphill beat and if it wasn't for the only boat behind them the event could have ended in certain tragedy.
From the swimmers point of view, things were not much better. Their automatic inflatable did not fire or open. Had they been unconscious they would have been dead. Fortunately he had the peace of mind to pull the manual release but said it was a forced thought. Do you know the expiration date on your auto vest? I thought so. His was 2010. Most don't even wear theirs, he was smart and lucky in that regard. His clothing was not conducive to floating or visibility, Jeans and black foul weather top. The inflatable he was wearing was not that visible to those that saw him. The inflatable portion of the vest was yellow. Today's vest are almost all vivid bright green/yellow. Two of my kids ordered new vests the next day because they discovered upon inspection their vests were yellow inside and they were both hydrostatic Mustang Survivals but both many years old.
The boat that rescued the MOB said they thought that they were seeing the race mark (which was an inflatable yellow in color). They tacked to make their approach and realized it was a swimmer. Even though they were on a Melges 24 they had difficulty slowing the boat enough for the individual to be collected. It was on their third pass that he was able to grab a line and drag the boat to a stop. Luckily the Melges is an open transom design with only about 6" from the water to the cockpit floor. They rolled him in like a dead fish as he was too exhausted to even help. Had the MOB had a personal VHF he could have coordinated his own rescue. All race boats monitor their VHF during the race for additional instructions. The Farr 40 that lost him immediately contacted the race committee once they determined they had a MOB situation. That VHF transmission was broadcast to the coast guard however they never responded or deployed even though they were less than 2 miles away.
In short, buy the best equipment that you can. Also redundancy is desirable as in having both a fixed and handheld unit. Too many boaters today are forgoing the fixed unit and opting only to carry a handheld. If the user with the handheld is the one that goes over the side then what? If the handheld disappears during a collision, grounding or knockdown then what? If the handheld is at the limit of its battery capacity then what? The same line of reasoning for having a handheld aboard would be... when a lightning hit fries the fixed unit or you suffer a dismasting then what. Ideally a fixed base unit would supplement each users personal handheld.
The is no single definitive answer, and then we add in SSB.
Safety is no accident.
Dale