The AIS carriage requirements apply only to commercial vessels subject to the Safety of Life at Sea (SOLAS) convention.
What about smaller vessels, such as tugs, workboats, fishing vessels and pleasure yachts, which will not be equipped with AIS? Will they be invisible to shipboard and AIS shore stations?
In some areas, such as inland rivers, which carry heavy commercial traffic, it is likely that port states will expand the AIS carriage requirements to include other craft, such as tug- barge combinations. Likewise, some nations may decide to use AIS technology to monitor fishing in their territorial waters by requiring commercial fishing vessels to be equipped with AIS.
There is considerable discussion in maritime circles about developing a sort of “mini-AIS”— simplified transponders that could be installed on non-SOLAS vessels. These devices might be shorter-range combined transmit/receive devices transmitting limited information at a reduced update rate, or in some cases “receive-only” terminals — receiving and displaying AIS data from other vessels, but not transmitting STDMA data. Specifications are yet to be determined for these types of equipment.