I took Two Lucky Fish out last night, just as the light was fading. What a lovely night. The pictures don’t really do it justice.
Anyway, I got a chance to test my new Shine Micro AIS-BX Class B transceiver underway. I contacted Seattle Traffic on VHF Channel 14, and they could NOT see my AIS signal on their Rescue 21 equipment. Why not? Possibly because of the lower-power Class B transmission specification.
So I hailed WSF Spokane, just a couple miles away. They indicated that they could see me, and had been watching for about ten minutes. I was all over the place, back and forth, slow and fast, so I can only assume that the AIS data they were seeing, updated only once every 30 seconds, looked…a little weird?
If all Class-B-equipped vessels behave as erratically as I did last night, it won’t take long before most commercial vessels will find a way to have their equipment ignore Class B targets. Just like the naysayers said they would!
On the other hand, Puget Sound waters were VERY crowded last night, due to the presence of many gillnetters. These boats set out long floating nets and then wait for the fish. Nobody wants to drive over a net; it would be a major hassle for everyone. So what happens when long, mostly invisible, drifting obstacles are scattered across a major shipping channel?
At one point, I heard Seattle Traffic direct a large vessel to use the opposite traffic lane, proceeding the wrong way in order to avoid a gillnetter who was being pushed into one of the lanes by the tide. There was lots of VHF chit-chat between the gillnetters and vessels underway, clarifying what was what and which side to pass on.
It was clear that the gillnetters were paying close attention to the talk on the vessel traffic channel. Some may have been equipped with AIS receivers, or they were just taking notes, because they had a very clear notion about which big vessels were headed their way, and they hailed them by name to negotiate details. The big vessels, on the other hand, could never be sure which gillnetter they were talking to. Confusing, but it seemed to work out.
Anyway, the reason I describe all this is that it’s the type of “situational awareness” challenge, even with the good weather and good visibility last night, that could really benefit from the proliferation of Class B AIS transponders. Imagine if all those fishing boats were visible on chartplotters? Imagine if vessels underway could identify the vessels in their path by name?
That’s how it’s all supposed to work. That’s the vision. It may take a while, both for the technology to proliferate and for the protocols to be developed and refined. It should be a fascinating process.
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Hi Tim,
A small technical point that I make in every class. Tide is the vertical movement of water and reaches a stand.
Current, the effects of set and drift, is the horizontal movement of water.
Here ends today’s lesson.
Richard
Most of the drift netting, which should be stopped all together, this time of year is for chum. Most of the chum are caught closer to shore and out of the shipping lanes. As you said the some guys get pulled pushed around but I dont think fishing in the lanes is the right way. Why does the unit only broadcast every 30 seconds??? seems like a design flaw to me.
Not a flaw…that’s all part of the “Class B” specification: lower power, less-frequent transmissions, less detail about the vessel.
The ability of some AIS equipment to not receive Class B AIS data is no surprise, since it is newly approved and Class A has been out for a while. The ‘early adopters’ of the Class B will (painlessly, hopefully) determine its limitations and shortcomings, and the needed changes will be made – eventually. It’s just as well that Class B is voluntary (for now…) since it’s to be expected that problems will exist that pre-adoption tests will not have uncovered. Having been an electronic technician for many years I’ve seen numerous examples of this.
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