Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship


      

Other Books by
Hal Roth
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Re: LOPs


Subject: Re: LOPs
From: Robert Owens (tugly@XXX.XXX)
Date: Wed Jun 23 1999 - 14:57:12 EDT


>Adding more lines (i.e., dashed D=ST lines) strikes me as potential
>chart clutter. The line's information can always be recovered by
>simply measuring the distance between an LOP and its advanced
>position. Speed and course should be on the track and similarly the
>LOP's should have the times at the start and end of the run. In cases
>where this line is needed, at some later time, to substantiate this
>information, I suppose it makes sense but I'm hard pressed to think of
>such a circumstance.

My Ramblings----

How about a sailboat making one or more tacks during that time. Or a power
boat that turns during that time. That would make recovering the distance
between the LOP"s original position and the advanced LOP after the fact
unusable. I believe that the dashed lines (construction lines) are optional.
If the LOP is labeled with time on the top than I don't believe a dash and 4
more digits is that cluttering. Just my opinion.
I also think that standardization is necessary so that at the end of your
shift the next guy will know exactly what has gone on without having to
remeasure and guess at what has gone on. In actual practice, when I am by
myself, a lot of liberties are taken.
As far as advancing twenty minutes at six knots- I ask about a morning
sight, noon sight, and evening sight. That would be advancing or retarding
hours. If you are heading somewhat East or West that would be 2 great speed
lines and a very nice track line.You take what you can get. A running fix is
better than an estimated fix or a DR but how much better? That's why
navigation is an art.

Bob Owens
Tugly





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