If all good things must come to an end, then it had to happen sooner or later. After 7 years and nearly 400 tips, DIY projects, yarns, and wordy expressions of opinion, we have decided to end our Monday posts and shut down the website. We will still be sharing tips and great information on our facebook page, and pictures of both the practical and eye candy variety on Instagram. So as we and technology move along, please move with us and like and follow us at either or both of those locations. And as always, feel free to swing by and say hi when you share an anchorage with Eurisko. Thanks for all the support. See you out there.

The Dangers of AIS

January 16, 2017

On our first Gulf Stream crossing after installing an AIS, I was excited to see lights on the horizon. I stared at them, did my usual clothes pin on the lifeline trick to see if he was going to pass in front or behind us, and then anxiously awaited the magical BEEP we had paid so much money for to confirm what my eyes could clearly see. And waited. And waited. I went below to look at the screen, thinking Dave may have muted the alarm when I wasn't looking. Nothing. After several minutes during which my clothes pin shouted its "Collision course!" decision, I finally decided the AIS was defective. I woke up Dave who was sleeping during his off-watch, hoping to be fresh upon landfall at sunrise. (We only cross at night. It's the only way for us to ensure we don't have to leave or enter in the dark. We won't do either.)

Our simple nav station

"I think the AIS is broken."
"Why would you assume that?"
"Because I can clearly see a ship right there and it's not on the screen."
"How big is your range set for?"
"Three miles."
"Then he's obviously farther away than 3 miles."

I had my doubts, but I couldn't stay below to argue the point any longer with this giant headed directly for us. My clothes pin still showed that his position relative to the boat had not changed. We were not going to clear each other, by my calculations.

[Danger Number 1: Electronics, which for us means an AIS since it's all we have besides a handheld GPS, make you distrust your time-tested methods of navigation that cannot lie without breaking natural laws such as physics and geometry.]

Finally, just when I was ready to disengage our Windpilot, Ziggy, and hand steer so I could bear off and be sure to go behind the behemoth, the AIS chirped at me. Aha! There he is. I ran below, scared to leave the cockpit unattended for long with the ship growing so large off our starboard side. The screen showed his name, length, width, draft, destination, type of vessel, course over ground, heading, cargo, what he had eaten for dinner, and a reassurance that our closest point of approach (CPA: AISs love acronyms) was over a mile. The BEEP had gotten Dave out of the pilot berth, and he stood beside me as I processed all this information.

[This is very similar, if not exactly what we have.]

"See, he's going to miss you. He's going to pass more than a mile behind you," and with that, my captain who had more confidence in his electronic crew member than his human one, went back to sleep.

[Danger Number 2: An AIS can be guilty of giving you TOO much information. In the time it takes to decipher it all and find the important bits, you may get run over by the exact ship that you are watching on the screen.]

My modern mind sat down in the cockpit quite comfortable in its knowledge that the ship was going to miss us. The AIS said so. But here's the kicker: my mathematical mind doesn't often allow my modern one to take over for long. It started immediately doing the calculations, forming geometric lines in my head. OK, so let's say he's there, I'm here. He's doing 17.6 knots, I'm doing, oh, anywhere between 4.2 and 5.3, depending on wind speed, direction and gusts, waves, strength of the Gulf Stream at that exact spot, and how much attention Ziggy is paying. So if I draw these two vectors that put the ship passing behind us at just over a mile, holy crap! That means that if the wind dies, if we hit a spot in the Stream that is less strong and we don't slide as far north for a few minutes as we are right now, if a wave knocks our bow around just enough to luff the sail for a second and it takes Ziggy a bit to recover, if a million little things, any of which can happen when you sail in the real world rather than on a screen, we're fucked.

[Danger Number 3: Electronic assurance that everything will be fine is based on current conditions, any of which can change. When it does, electronics REACT to the new situation, but perhaps too late for you and your boat. Human crew can be PROACTIVE and prevent the situation from ever occurring.]

So there I sat, with my hand on the tiller, ready to disengage Ziggy, throw over the tiller, and bear off to pass behind the now enormous ship when I got too freaked out to hold the course any longer. Except I was already too freaked out. I would NEVER, and SHOULD have NEVER, let a ship get that close to us before we had AIS. I would have checked my clothes pin a few times, realized we were going to pass too close for comfort and have altered course MILES ago. I would have thought he was right there (instead of over 3 miles out) and I would have considered this "over a mile" CPA the same as a direct hit. I have never passed so close to a ship that was not anchored and I hope to never do so again. Because from that moment on, I left the AIS on and welcomed its BEEP when a ship was near (because you never know when you might fall asleep on watch) but I have not once since that time changed how I sail Eurisko. If I feel like the little dot on the horizon is too close, I alter course. I don't care what the stupid little machine says or how it may laugh at me, knowing that we cannot possibly collide with that ship. Because I know that when you're dealing with Mother Nature, it IS possible, regardless of what it shows on the little screen.

Do I still like our AIS? Oh, absolutely! It provides a nice green night light down below so I don't have to light a kerosene light during watch change. And it is nice to be able to call a ship by its name to verify its course and intentions because, though the box may be able to tell me what is happening right now, it can't predict the future. We need to sail our home like we always have: cautiously, prudently, and by trusting in clothes pin navigation.

MONDAY we'll share one of our deck repair projects.


Connie McBride's work has been published in Good Old Boat, Sail Magazine, Small Craft Advisor, Cruising World, All at Sea, and Blue Water Sailing. As a full-time liveaboard cruiser for over 15 years, she has written several books and in her spare time, well, who has spare time?

It's here! My latest book, Years of Ideas from a Simple Sailor is now available on Amazon.

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