Lessons Learned


How QMC Burris and I earned our first Navy/Marine Corps Achievement Medals

These are a couple of my navigational "lessons learned."
They are not found in any book, but they do work.

(This may be boring to anyone not into Navigation)

More accurate Radar FixesMore accurate Celestial Fixes | Shooting celestial by yourself

1- More accurate Radar Fixes

QM's (Quartermaster) and OS's (Operation Specialist, formerly RD, Radar operator) are required to independently fix the ship's position and compare the fixes.
When offshore Bridge and CIC (Combat Information Center) fixes seem to agree, however, when close to shore or during Nav Detail there are disagreements between the bridge and CIC.  So who is really correct? The answer is, both and neither.  The problem is with scale.

When offshore both QMs and OSs use the latitude scale of the chart to measure range for radar fixes. 
The problem comes when we come close to land.
Harbor charts conveniently provide scales in yards, miles and nautical miles, but, they are not the same scale used by radars.   I thought there had to be a common measurement in order to make things work.

Where as: radars display range as 2000 yd = 1 nautical mile.
And where as: 1' (or 60") of latitude = 1 nautical mile.
Therefore: 1'
(or 60") of latitude = 2000yd.

If we work the math further we find that;
1/2 nautical mile or 1000yd  = 30" of latitude
1/4 nautical mile or 500yd = 15"of latitude
100 nautical yd = 3" of latitude.
At the smallest unit 1 nautical yd = .03" of latitude.

If both bridge and CIC constructed range scales based on the latitude scale onto margin of the harbor charts, the radar fixes will become far more accurate and will agree with bridge visual fixes.

When plotting areas on a chart such as mine fields, amphibious boat lanes, etc. simply convert yards to minutes of latitude and then use the latitude scale of the chart to measure those distances on the chart.
For example: You are required to measure 1568 yd.
Just multiply 1568yd x .03 which equals 47.04" of Lat.

The Lat scales on harbor charts will let you measure that close.

The increased accuracy is incredible!

2 - Instant Plotting and Quick Bearing and Ranges

When piloting, the bearing and range to a navigation aid or hazard is often required and must be determined quickly.

For many decades RD's and OS's have used a scaled PMP blade for quick plotting on the DRT plotting table.  Bridge personnel can do the same thing with their charts. 

Construct chart scales on plain paper using the Lat scales as mentioned above. 
Use some art work and make your scales look similar to those printed on the charts.  The nicer your scales look, the easier they are to use.
Label the scales with the chart scale and common chart numbers that use that scale.  Tape the scale to the underside of a clear plastic PMP blade.  Create more so you have a collection of PMP blades with various scales, one for each of your usual harbor charts.

When bearing and range are needed, simply lay down the PMP blade and read the results.  Bearing and range are read in one motion.  No more reaching across with dividers.

REMEMBER!!!  When you shift charts, don't forget to change to the PMP blade to the matching chart scale!

How this idea came about:

I first incorporated the idea of using a scale on my PMP blade while performing PCS/UW (Primary Control Ship/Underway) during Amphibious RefTra (Amphibious Refresher Training) aboard USS Durham (LKA-114) in 1982.

For those who have never done it, it is a very busy time!
The bridge is required to visually fix the ships position every 30 sec.  After each fix, bridge then plots a 30 sec DR for the next fix.  A bearing and range from that DR to the right flank of boat lane is reported to CIC.  CIC then plots that DR position on their chart.  By then the 30 sec has elapsed and based on the DR, CIC uses radar bearing and range to fix the position of the wave commander in the boat lane and then directs the wave commander to come right, come left, speed up, or slow down, etc.  This procedure is repeated every 30 sec while the ship maneuvers to maintain the best defensive aspect to the beach.  Object:  Direct landing craft to the beach so that they drop ramps exactly at H hour,  +/-  30 sec.

No one told me how to do this.  I just taped to a scale to the PMP blade, using scales as mentioned above, and instant plotting of the DR and the instant reading of bearing and range to the boat lane became literally a flip of the wrist!  Using these techniques, USS Durham passed Amphib RefTra with blazing scores.  (I was never recognized for my innovation.)

From an amphibious ship I was transferred to a Minesweeper and minefield navigation presented a very similar problem.
I used the same techniques to layout mine fields and then navigated through them and plotted mine positions with extreme precision during MRCI (Mine Readiness Certification Inspection).   USS Excel
passed MRCI with such blazing scores that I was awarded a Navy/Marine Corps Achievement Medal from MineGruOne for my innovation.

On Excel I was relieved by my good friend, Rick Burris, and I showed him my technique.  He then used it while conducting mine sweeping operations in the Persian Gulf and was also awarded Navy/Marine Corps Achievement medal.


How to Shoot More Accurate Celestial Fixes

Most LOPs (lines of Position) rarely intersect to form a perfect asterisk, which leaves the navigator to interpenetrate the fix, but there is an easy way to eliminate a simple error.

DIP is the correction for height of eye above the sea.  Most Navigators have the measured their height of eye while pier side, but, that height changes when at sea.  In a relatively smooth 10 foot sea, ask your self, did I shoot at the top or the bottom of the wave?  It makes a real difference in computing HO and can throw off an LOP by more than a few miles.  The elimination of this shooting error is easy.  Just show up early to shoot and just relax.

It is how you relax that makes the difference.  Lean against a bulkhead for 5 min or more and just feel the motion of the ship.  You will notice a pattern in the ships motion, up, down, right, left hard up, down, right left, etc.  Within that pattern there will be a few seconds when the ship sits perfectly still.  (To me the ship goes "mush")  That is the moment the ship is sitting at zero - perfect sea level - and your measured DIP is correct.

While shooting, feel the pattern of the motion of the ship.  Wait for the "mush" and that is when you "Mark!"  Do this and your fixes will tighten up.

How to Shoot Celestial by Yourself

I was on an undermanned ship and often didn't have anyone to record for me so I developed these procedures.  They actually work well.

Sun lines are easy.  Hold a watch in your hand.  When you "Mark" take your hand off the sextant and remember the time on the watch.  (Seconds is the important part)  Write down the time you remember and then then read the hs off the sextant.

LAN is a little harder.  The thing to remember is that you are observing the sun as it rises.  Each time you observe the sun go up, adjust the hs and note a new time. (Only min and sec)  When the sun dips down do nothing - Take your hand off the sextant.  Adjust the sextant and note a new time ONLY while the sun continues to rise.  When it is obvious that the sun is on the way down, you are done.  Write down the last time remembered and read hs off the sextant. That is LAN

Morning and evening stars requires the use of a small personal recorder. (A mike clipped to the collar makes it better)  Prepare the shot and then start the recorder.  Do NOT turn it off and start talking to yourself.  Talking out loud perform a time.  "At the mark the time will be . . ."   Then start talking to yourself.  "OK, coming out on the bridge wing.  Hm, a little early.  Stars should start coming out to the east next.  Should see Arteries.  It should be just abaft the beam.  OK, there it is.  Got a horizon.  OK, Ive got it . . . ready . . . Standby . . . MARK!"  Now wait a few moments, then read the hs and move on to the next star.  Back in the chart room replay the recorder.  Now you are playing the role of celestial recorder.  Listen to the time tick and start a stop watch.  Listen and write down the "Mark" times and the corresponding hs.

It does take a little longer, but, you have the shot.