Puget Sound VTS Does Not See Class B AIS

This is something I did not know.

From April 2015 Waggoner's Pacific Northwest:

We recently saw some discussion online about whether or not Puget Sound VTS can see AIS Class B targets. We checked directly with Puget Sound VTS, and they told us that their equipment cannot receive AIS Class B signals. Additionally, they have no timeline for when their equipment might be upgraded in order to see AIS Class B.

Canadian VTS can see AIS Class B, but they stressed that non-participating vessels do not have any right of way in VTS lanes.

Bottom-line: even if you transmit AIS Class B, don't expect to be seen by VTS.

This very subject was covered extensively in the recent thread titled "Automatic Identification Systems". More info there, including that San Francisco VTS is able to monitor Class B. Each VTS Center apparently has different capabilities.

However, I'm still curious to know if the Washingtom State Ferries and/or BC Ferries monitor Class B AIS.

Nsail: "However, I'm still curious to know if the Washingtom State Ferries and/or BC Ferries monitor Class B AIS."

Don't know about BC Ferries, but early last year, a source informed me that WSF now has a policy about not monitoring Class B. I've also heard that it is optional in practice.

It's important to know that many Class A installations have the option to receive or not receive Class B. The reason is that if there is just too many AIS targets, the level of safety for a large vessel can be compromised through an overload of collision avoidance assessments by the navigation team.

I know this sounds bad for small vessels choosing to install Class B, but in congested waters, it is still very important to just stay out of the way. Jay.

This is very interesting... not monitoring both classes of AIS is a bit like sticking one's head into the sand... just because they choose to not monitor class B doesn't make the boats go away. I find using AIS I don't need to watch a approaching boat as long to decide what they are doing.. giving me time to look at all the other targets in the area.

It is a very strange concept to me.

HOLLYWOOD

I actually don't believe the wsf don't monitor all AIS.

For is that's the case, it's a lawyer's wet dream.

I added that bit to Waggoner's Pacific Northwest Boating based on the discussion I'd seen here. I talked to the director of Puget Sound VTS and he indicated they may get the capability to monitor AIS class B in the next several years, but indicated they would likely heavily filter it.

As far as Washington State Ferries, they certainly have the ability to see AIS class B targets. They've called me in overtaking situations and the only way they'd have gotten the name of my boat is from their AIS display.

hollywood8118 said:

This is very interesting... not monitoring both classes of AIS is a bit like sticking one's head into the sand... just because they choose to not monitor class B doesn't make the boats go away. I find using AIS I don't need to watch a approaching boat as long to decide what they are doing.. giving me time to look at all the other targets in the area.

It is a very strange concept to me.

HOLLYWOOD

Click to expand...

I agree. I can't believe any captain would risk his license by not using every tool available to assess their situation and locate traffic. How would you justify that action after you flatten a boat and kill a few people? You would be the next Sachetti.

Here is what I have heard from commercial sources. AIS filtering by target size, speed, range and course is not uncommon by commercial vessels. Similar filtering is done by radar systems. This general practice, if common, seems logical.

Most common in my experience are tow boats calling my Class B information and saying get out of their way, we slow trawlers are a real nuisance to some.

Here is what I have observed from Washington and BC ferries. When I am in their proximity zone there have been VHF communications initiated by ferries as to my intentions.

Here is what I have observed for cruise ships. They watch out for all AIS targets.

A Captain is fairly independent, and as suggested by others it seems prudent to monitor targets via any means that are nearing proximity zones and for sure danger zones.