First I've heard of it. So I've done a very small amount of research, and found that AIS is a VHF-based system. VHF is a line-of-sight signal - i.e. the radio wave travels in a straight line and can be blocked by physical obstructions such as waves. If you're up to your neck in water, after your dive boat's abandoned you, the aerial is going to be virtually at sea level, so I'm dubious as to how much range this device will have, especially in big seas.
I raised the same point in the other thread about the Nautilus emergency VHF system. Didn't get an answer.
Until someone does a test of how far these things actually broadcast in the conditions you're likely to encounter in UK diving, I'd be wary.
a) the transmission range is given as 4 miles.. so if no AIS fitted boat (or land based AIS receiver) is in that range then it will not show up.
b) it does not say which type it is, Type A or Type B. Type A AIS is the mandatory fit for vessels over 300 tonnes. Type B is the voluntary fit to other vessels. In busy areas such as shipping lanes etc where lots of Type A vessels are transmitting, they take priority and Type B transmissions can get hidden or delayed
c) At present, only around 4 RNLI lifeboats are fitted with AIS receivers (not sure about independents).
For the time being I would say a small EPIRB would be the better choice for diving where there is a significant risk of getting lost . These initiate a distress call by satellite including GPS coordinates and also have a homing signal that can be picked up by direction finding equipment fitted to lifeboats and SAR helicopters.
This however is maybe a better evolution of AIS...it has two levels of functionality, one for the dive boat itself to keep track of divers and another emergency function similar to the McMurdo one. It does however need the dive boat to be fitted with the tracking device. easyDIVE-POS A051