- Reaction score
- 365
- Points
- 930
Lumber said:I'm surprised you're surprised.
From the time I first sailed on MARS II back in '08 to now, the rule has always been that the Radar is to be left in True Motion at all time, and you are only to switch it to Relative Motion for a few moments before switching it back.
When I sailed with the USN '09, they did it the opposite, and it made total sense to me. Why not leave the radar in a way that allows you to take one look and see if someone is going to hit you?
However, my personal opinion on that has now changed. With experience, you don't need relative motion lines. I kind take a quick look at radar, and based on our leader lines, I can make a quick and more-or-less accurate assessment of whether a close quarters situation is developping with another vessel. This cues me to read the CPA from ARPA, take bearing, and switch to relative motion. Since the radar is in true motion, I know which direction all these ships are actually facing, which helps me build an accurate mental picture in my mind, which you can't do with relative motion leaders on.
:2c:
/tangent
I went ashore in '04 and returned in '10 - lots of changes in that time, I think.
I agree with your point "with experience..." but that kind of mental assessment you described is completely 'experience' dependent, and an ideal way for the error chain to start. A Wardroom full of pre-NOPQ Subbies in, for example, the Arctic, does not scream 'experience'. Too often I have had an overly tired OOW - even occasionally, an experienced one - think he/she has hooked the appropriate contact, but in realty the tote was displaying info for some other contact. That arises in part because the critical component - briefly switching to Relative Motion - doesn't always happen.
I am not against True Motion at all - it is particularly helpful when conducting Blind Pilotage and help to paint the rest of the picture in all circumstances. I'm not sure there is a 'right' answer...
/end tangent