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post #896 of Old 11-24-2012
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Re: HMS Bounty in trouble...

Originally Posted by chef2sail View Post

I am not sure if I understand you but anyway what you say makes no sense. I don't know if you used to navigate at night without a plotter and if you would do so I don't understand what is your doubt. As I hope you know navigation without a plotter use triangulation and azimuths to find your position in a chart.

At night many times you simply lack references to get a good fix and even navigation lights on the shore can be difficult to sort out from the middle of other lights and that could on coastal navigation make things difficult if you have to avoid some rocks or any other obstacles. Sometimes the precision you could get sometimes regarding your position was rather poor and I am talking about several miles. That could make things dangerous and therefore it would be better to wait for day light.

With a plotter sometimes you get an error (that is due not to the GPS imprecision put mostly to different chart projections systems that not always are a match to the one used in the chart on the plotter) but is never an error superior to a mile and most of the time is an error not superior to 300m. If you can navigate giving always a berth of more than one mile regarding your position on the plotter regarding any obstacle (rocks) you will not have any problem. Off course that does not dispense the corroboration of the plotter information by the information given by the different navigation lights.

So yes, today with a plotter I can do with a sufficient safety margin night navigation that without a plotter (given the bigger incertitude) I would not have attempted.

I am really baffled that you cannot understand this. Do you sail and cruise at night?


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