Feb 20

AIS–worth every penny

Tag: navigationmattholmes @ 2:00 pm

an example of why the AIS has been awesome.

In the middle of Karen and my night watch between Santa Cruz and Catalina, while we were still on the edge of the shipping lane, we were enveloped in dense fog.  I aimed us out of the shipping lane and turned on the radar, but the AIS was the true hero.

We had a 505′ container ship come up behind us doing 20 knots, and because I had the AIS and I could see where they were and where they were headed the whole time, I didn’t even have a need to hail them on the VHF, and never had any reason to worry about them.  They ended up passing less than a half mile to port of us–we never saw or heard them.  During all of this, the radar was most unhelpful.  When the ship was a mile away I could see her as a small blob on the radar (largely because I knew where to look from the AIS, and as she passed us at a half mile, the radar showed her as an amorphous blob extending for over 125 degrees worth of our horizon–as if an entire island was headed our way.

I took two screenshots from the AIS while it was happening, to show off here.  The first one shows the container ship passing us, the second one shows how we could see all sorts of other traffic headed out of LA, through which we passed uneventfully later that night.

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