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On 4/15/2015 5:26 AM, David Pike wrote:
>     Lu wrote. I think that pretty well summarizes it.   Technically, a
>     RB expressed as an angle is always 0-360 clockwise from the bow.
>     But you can make it "to the port/starboard" by making it clear that
>     you are expressing things that way.

Thank you gentlemen. I understood the concept but found the vocabulary
vague. While we often see phrases such as "doubling the angle on the
bow" finding a definition of "angle on the bow" is like finding old
hens' teeth. I looked in Dutton's, Chapman's, Annapolis and Bowditch
etc. Nowhere that I could see did it show up in indexes or glossaries. I
just found it vexing that the "angle on the bow" term is used in
describing how to perform a procedure without defining the term.

Googling it yielded references to submarine torpedo firing solutions,
where the definition does seem to sync up with the usage in doubling the
angle on the bow for surface craft. Angle on the bow appears to be from
the observer's bow to the target, while target angle is from the
target's bow to the observer.

At any rate, it any of you visited the URL I posted it is a wonderful
example of the web dispensing inaccurate information. Below is perhaps
my favorite example from their pelorus page. In what parallel universe
does 350+45=435, 435-360=35, or a compass revert to 0 at 350 degrees?

"Converting Relative Bearings to Degrees Magnetic
...On our return course, compass heading of 350°M, the tower would now
lie on or starboard side. When the tower is 45° off our starboard side
our compass bearing would be 35°M (350 + 45 = 435 - 360, since our
compass reverts to zero at 350°, gives us 35°)."

It's comforting to know I'm not the dumbest person in the room :-)

   

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