Author Topic: Sharing a confession for learning  (Read 3952 times)

sy_Anniina

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Sharing a confession for learning
« on: January 07 2021, 11:41 »
As an occasional reader of Yachting Monthly "Confessions of the month", as well as from my professional background, I like to encourage learning from mistakes - both from others and my own.

I would like to start by sharing my confession that appeared in Jan-2021 issue of YM as a starter:

After an exhausting long day of hand-steering in 3+ meter seas from Visby, Gotland to Kalmar Sound, Sweden, we approached a combined marina and commercial harbor for a much-needed rest. It was around midnight, when suddenly our AIS VHF unit (not connected to chart plotter) gave an alarm of a vessel whose closest point of approach (CPA) was less than 0.2 nautical miles in 10 minutes.

Against the city lights in rain I could see a couple of big ships with lit decks. The tiny AIS screen on the VHF unit gave me the ship’s name and I promptly called them on VHF:

Fantasia, Fantasia, Fantasia, This is s/y Anniina.

Fantasia

We are progressing under sail, approaching you from bearing 095° and have CPA in 10 minutes in less than 0.2 nautical miles, do you see us on your radar?

Negative - we don't see you.

We are a progressing under sail and seem to be passing close.

For your information we are a tanker…


We concluded from their abrupt statement that they could not care less of us approaching so we followed their lights carefully and passed what seemed like safe distance while they appeared if not stationary, only travelling minimal speed. I later double-checked their AIS status and realized they had said:

We are at anchor.

With all the deck and city lights, it was next to impossible judge from lanterns whether they were anchored or motoring only slowly. Lesson learned - check also the AIS status message + integrate AIS display to plotter so you don't have to run back and forth between helm and chart table to add AIS targets to situational awareness when tired.

BR,

Tommi
s/y Anniina

Yngmar

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Re: Sharing a confession for learning
« Reply #1 on: January 07 2021, 12:19 »
OpenCPN's AIS display is pretty great. For targets at anchor, a black ball is overlaid. And you can also tell which are making way because they're pooping out a purple line behind them:



And if enabled, it visually shows you the CPA (the point where your two predicted routes are at their closest point).
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Odysseus

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Re: Sharing a confession for learning
« Reply #2 on: January 07 2021, 15:38 »
I have open CPN also Navionics , I would like to ask your statement, "enabled" precisely what is required.

Odysseus
Odysseus

Markus

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Re: Sharing a confession for learning
« Reply #3 on: January 08 2021, 10:39 »
OpenCPN's AIS display is pretty great. For targets at anchor, a black ball is overlaid. And you can also tell which are making way because they're pooping out a purple line behind them:



And if enabled, it visually shows you the CPA (the point where your two predicted routes are at their closest point).

That looks super-clear - thanks for the tip! But which chart package do you use with OpenCPN? The last time I looked, it seemed difficult to find up-to-date charts for OpenCPN with reasonable fees compared to getting the whole of Europe for ~50 eur for Navionics. Or do you use OpenCPN only for AIS?


SYJetzt

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Re: Sharing a confession for learning
« Reply #4 on: January 08 2021, 11:11 »
I use opencpn with o-charts (https://o-charts.org/shop/en/) on my PC-System as well as on my tablet (Opencpn for Android). Price for these charts is little higher than for navionics, but you can use one chart-licence for both systems. You can purchase the charts (up to date!) as abo, which includes update-service for 1 year. After the 1-year- period you keep the charts on your system (but you don't have updates anymore). Quality of charts seem to be of different quality in detail depending on the covered area, but you can check a chart example in detail before purchasing. I use the greek and adriatic waters charts, which are pretty fine.   

Yngmar

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Re: Sharing a confession for learning
« Reply #5 on: January 08 2021, 11:24 »
Odysseus, just checked, they're on by default, so you'll always get them.

Markus, we use the widely shared C-Maps from 2011 (alongside current Navionics on a phone) and sometimes o-charts for the area we're in.

Not much difference, but the Navionics Sonarchart is not to be missed, especially for anchoring. The Navionics software however is crap and keeps freezing when in areas with intermittent connectivity, as it constantly tries to contact their servers in the background for no good reason. Putting the phone into Airplane mode helps, but then you can't check the weather. Shouldn't be used for navigation really! :P
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Markus

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Re: Sharing a confession for learning
« Reply #6 on: January 09 2021, 19:05 »
Markus, we use the widely shared C-Maps from 2011 (alongside current Navionics on a phone) and sometimes o-charts for the area we're in.

Thanks, I think I will give OpenCPN another try when I get to boat next time.