Sea Stories

SPAN Trainer Session

Steve Ewing

This is something I came across in an old notebook. From 1994 to 1997 I was at Submarine Group Two Operations, and as such I helped do the inspections for ships in the shipyard. One of these inspections involved observing the piloting team in the Submarine Piloting and Navigation (SPAN) trainer in New London; a simulator with a scope, radar, and Mark 19 plotting tables.

I thought it might bring back a few memories to show what went into my notebook on such occasions. This was a submarine that was probably in Portsmouth Naval Shipyard, down for a week of training and evaluation. They are rusty, but keep in mind that I was looking for mistakes: that's what I was there for.

The format of this is my original notes in italics, followed by a fuller explanation of what I was jotting down. For some of these, after so much time I am not too certain of what my actual complaint was: in those cases I made an educated guess. I think these notes are actually a rewrite of my "heat of battle" notes, written out a bit for reference during the after-action critique.

The piloting party consisted of the Navigator, scope operator, primary plotter, bearing recorder, secondary plotter, secondary recorder, radar operator, and fathometer operator. Sometimes a contact coordinator was used. The OOD and COW (Chief of the Watch) were played by the trainer operator.


Radios? Plotter, Nav
--the piloting team should try using voice-activated radios between the bearing recorder and scope to aid communications.

13212 no danger bearing, rg (on primary, off buoy)
-- there was no danger bearing or range on the secondary chart (a tripwire to indicate the ship is standing into danger). On the primary chart, it was plotted to a buoy (floating aids to navigation are not reliable)

F2F: no repeat-back to COW
-- poor face-to-face communications

posit log: supplementary codes not approved by Nav
-- administrative hit: any additions to the logs, such as a list of non-standard abbreviations for the position log, have to be signed by the Nav and posted permanently in the log

Primary Plot

Recorder logging navaid AV vice AT
-- the recorder is using the wrong abbreviation for the navaid.

recorder calls brg, navaid vice reverse
-- he should say, for example, "Race Rock: zero three seven"

Plotter: loss of true bearing: good catch
--when his fix didn't cut, he realized the cause and reported it

Plotter: good recommendation to change navaids for relative spread
-- it's difficult to use a three-arm protractor when the aids are too close together

Automatic use of three-arm?
-- they were on the long, straight 279 leg; the primary plotter could have set the plotter arm to the ship's course and used that to plot relative bearings: easier

Nav: loss of true: report casualty to piloting party, bridge; shoot round in relative
-- When they had the loss of true bearing casualty, the Navigator did not formally announce it to the piloting party, nor inform the bridge; and should immediately shoot another round using relative bearings

Contact plotted roughly on primary; better plot would give cse/spd
-- accurately plotting range and bearing to the contact on two successive rounds would let them pass a good course and speed of the contact to the contact coordinator

1:50 sounding checked, fath not told, fath didn't push
-- at each round, the fathometer operator reports the sounding; the plotter matches it to the fix, and reports, "Sounding checks" or "Sounding doesn't check". The fathometer operator records this in his log (usually just by putting a check next to the sounding). In this case, it wasn't reported to the fathometer operator, and he didn't pester the plotter for it.

Chart shift to 13212: right on edge of chart; plotted range with dividers to different aid
-- when they went to the new chart, they were right on the edge of the new chart; and (I think: I am a little fuzzy on this) the plotter used a different navaid to plot the range than he did to plot the bearing; in other words, instead of using range and bearing to a single navaid, or laying down the bearings of two navaids from the previous round, he plotted one bearing and measured the range to another, and then transferred that range to the new chart. This was probably because the other two navaids shot for the round were not on the new chart.

Primary shift to radar: radar says will shoot SHAG; not on chart
-- another drill: reduced visibility. When the primary began to use radar ranges, the radar operator called SHAG as one of his navaids; it was off the primary chart, but the radar operator was not told until after the round: he could otherwise have used something that was on the chart

Secondary passed fix card while on sep. chart: card not labeled with chart #
-- 3x5 cards are used to pass fixes between plots: if the two plots are on the same chart, you can mark the fix as one corner, and tick where the card crosses the lat/long lines. In this case, the plots were on different charts, and the card was not properly labeled with the chart number.

Fischer plot?
--the radar was not fischer plotting (marking the outlines of his returns on a transparent overlay disk for matching to the chart). This was intentional; the question was, why not?

Plot buoys
-- the entrance buoys on the approach to New London were not being plotted to verify their position: there is typically a crossing current (at least in the trainer, you never get to time it for slack water) as you come up on the entrance buoys

t 2:11 no fix, shoot another; secondary was shifting charts, no backup. Turned while secondary still shifting, no backup
-- primary wasn't able to get a good fix: the secondary plot was shifting charts and was unable to provide a backup (shifting during a fix? Did they shift before the "no fix" report? Probably they got their fix and shifted, in order to be done by the next round). The ship turned while secondary was still in the process of shifting charts: the piloting team had no backup for the primary plot until they were done.

Erase old DR after turn
-- basic piloting: after your new DR is laid out, erase the old one.

Secondary: 30 sec GPS fixes: plotting lat/long not very doable
-- This piloting team plotted GPS latitude and longitude (gotten in the trainer from a printer on demand); on the scale chart used, with the way the degree increments are labeled, it is not easy to plot a lat/long every thirty seconds and maintain the cyclic routine (fix, fix label, DR, DR). A thirty-second round under such circumstances is counter-productive

355 leg

Nav recs 340; eyeballs good course. Set 355 2kts. Thought was to west
-- the Navigator recommended a course without measuring it, using his calibrated eyeball. The actual current was set 355, drift 2 knots; he thought it was more westerly.

Time 2:22 fix, radar shooting RR, WP, LG: they all line up; pick up ND after fix; need GP, PINE
-- the radar operator shot three navaids that gave concentric circles for ranges: no cross-ranges. They need to look ahead and pick up new navaids in advance, such as GP and PINE, that will give good cross-ranges.

Radar not told when primary says poor aids; he can't report what he has
-- the radar operator and plotter need to work together to determine what navaids to use; poor communication in this case

Repeatedly shot vis rounds while turning
-- with the ship turning, it is difficult to shoot an accurate fix: to mark the bearing, the scope has to turn to stay on it. In the trainer, you can't shoot during a turn; the picture jumps and the bearings lag the scope. You have to shoot a round before the turn, and shoot a round when steady: basic piloting

Shot on time vice stdy
-- the bearing recorder is the timekeeper: he calls out when it is time to shoot a round. During a turn, he calls the round when steady on course, and starts counting over from then. In this case, the bearing recorder ignored the turn and just called the round based on the time.

Scope didn't shoot on time, recorder changed time w/o report to Nav
-- the scope operator missed the round, so the bearing recorder called the round on the next minute: he failed to inform the Navigator of this change.

Last set/drift from secondary at 2:16; Nav basing cse, etc. on data turning every fix
-- there are several short legs going through the Race in the approaches to New London; the Navigator was recommending a new course after every fix, without steadying down enough to get a good set and drift.

OOD orders LFR! Rec course? Slow?
-- The Officer of the Deck ordered Left Full Rudder. The Navigator should give a recommended course to avoid whatever caused the turn, and report distance to shoal water in the direction the ship is turning, and perhaps recommending slowing.

Back   Back to Sea Story page

HOME Articles Sea Stories Book List
Links Deck Log Contribute About