"Direct Commander E. M. Block prorep port CV—may be duty as Navigator.” Everything looked good about those orders—I’d been trying to get CV duty, but that word Navigator stared me in the face. The navy profs at the academy years ago had told me that there’d come a day . . . ! Anybody have a Dutton and a watch officer’s guide? My reactions were, I believe, normal.
Upon reporting I found that duty as navigator in the combat area was not quite as outlined in the books. The actual deck and mooring board took up most of the time, but navigation still had to be done, and at times under extremely adverse conditions. I inherited some tricks of the trade not in the books, acquired some from a very able ex-navigator skipper, Captain T. H. Robbins, and devised still others myself. Some new, some old as the art itself, but still not available to the navigator except by hearsay. The purpose of this article is to record some of them for the benefit of the naval officers still to be confronted with similar orders. I will not attempt to go far into the tactical part of a navigator’s duties, nor shall I be able to discuss classified navigational equipment, except to say that there are times when everything you have is not enough, and to depend solely upon navigational aids which can be denied you by the enemy or natural conditions is folly. Navigation is still, at times, just getting every bit of information you can, analyzing it, and throwing in a few “ifs” and a prayer.
Perhaps it would be a good idea to start saying something. Here’s my bag of tricks!
Running up stars by dead-reckoning tracer or dead-reckoning indicator.—Stars are usually taken in the combat area with the ship under a combination of zigzag plan, emergency turns, course changes, and maneuvers to operate aircraft. The old system of running up stars by DR takes time, is laborious, and is not as accurate as utilizing your DRT or DRI. I prefer the DRT light through a plotting sheet. The scheme is merely to have a quartermaster mark your light or take a DRI reading every five minutes while you are taking sights. With drafting machine and triangle set your dividers the distance your line is from the mark for the time you took your sight—interpolating by eye between the five-minute runs—and draw your line the same distance from the mark at the time you are using for your fix. Simple, nothing startling or brilliant, but many have not heard of it, although the word has been getting around.
Doubtful observations.—Then comes that time when you’d give a lot for a sight, and get doubtful observations. There are several things you can do to improve the situation. First, with a bad horizon get as low as you can. I know it’s a long trek to the fantail or forecastle from the chart house, but decreasing your height of eye brings your horizon closer and sometimes works miracles. Try it 1 Next, take as many sights as you can over a period of about three minutes—longer, if you can’t get many. Let’s use a patrol plane stunt on these observations, with a few refinements. Plot your sights on a graph, altitude versus time (I keep an ample supply of special graph paper in the chart house), as in Fig. 1. Now take a look and see if they all fall in a straight line. Under normal conditions they will, but these conditions aren’t normal, and they look pretty erratic. We don’t know just how to draw a line through them. Let’s wait a minute before trying to guess at how the line runs, break out HO 214 and work the sight for about the middle of the period of time involved. When you pick out delta d also record delta t. Finish working your computed altitude and get that crossed off. We still are missing that very important item, observed altitude. Take your delta t and multiply it by 0.15. Believe it or not, your answer is the change in minutes of arc in the elevation of the body per minute of time. We now have the direction our line should run through our sights on the graph, by taking a starting point, moving over one minute of time, and up or down .15 delta e minutes of arc, depending upon whether the body is rising or setting. Now with a triangle and a pair of parallel rulers move this slope through your sights so that they fall equally as much above as below, draw your line, and pick off your observed altitude for the time you worked your sight. I will assure you that you have come pretty close to making a good sight out of bad ones, unless you have shot a false horizon instead of the real one. I use this method to check my sights when my fix is not close enough to a point to suit me. Also, on my suns I have the quarter-master plot them on a graph while I work my sight. If they don’t fall in a straight line I correct my observed altitude accordingly. My JO’s like to plot their suns and pick a sight on the line to work. Take your choice.
Figure 1 illustrates a plot of actual sights taken with a fuzzy horizon and the sun behind a light layer of clouds. Bogies were on the screen, incidentally, and the sights and original plot were definitely not for publication purposes. Without the use of delta t you can easily visualize several other slopes fitting the picture just as well.
Running up sun lines.—I like a sun line every hour; a noon fix with LAN, a sun an hour before, and one an hour after. However, you may get only a few suns during the day and want to combine them all. Trying to run them up for a long period of time sometimes results in a picture about as sad as a sailor at mast. Under these conditions my next step is similar to the scheme of plotting soundings on tracing paper and fitting them into the track. I plot my estimated positions for the time of my sights, on tracing paper, and fit them into the sun lines. A quick check can be made by dividers to see how runs fit with the sun lines. In the back of your mind you must always remember any doubtful sights in order properly to evaluate them. Occasionally, however, you cannot arrive at a logical answer using this scheme. There is another that I sometimes resort to because it gives me a position that takes into account all sun lines, yet is the least distance from the dead-reckoning position. Sort of a “Dag- wood sandwich” type of computed point. Hold your hat! I take may first sight, erect a perpendicular from my DR and get my computed point. I then run that forward with current to my next sight, and use it instead of DR to get a new computed point from my second sun and continue the process. Thus all of my sights combine to give me a single point which seems to work out pretty well. Don’t ask me why! I believe it’s better than trying to stick your finger into that awful mess and say “Here!” It looks more scientific, anyway. Thank heaven things don’t get to the point where you need to go to these extremes often!
Current.—The current charts now available (H.O. misc. No. 10,058A) are a navigator’s dream. They do not give you all the data you must apply, however, but only one element of it. The navigator who does not apply his wind to his set and drift is not getting his best E. P.—and at times wind is a great factor. There is no information available to tell you how much wind to use, but trial and error will give you a fair answer. I take 2.5 per cent of wind force, regardless of heading, and apply it in the direction opposite from which the wind is coming, then vector this with the current from the current charts. Mine is undoubtedly not the correct answer, but it is far closer than not using wind at all, and has given me good results. Percentage would, of course, vary with different types of ships.
Height of bodies.—Every navigator has his own opinion on how low a body can be and be good for observations. I might as well put in my oar. I try to find stars as close to 15° as possible, and will go as low as 8°. High stars are not as accurate because of the great change you get by not swinging your arc exactly below the body. My low limit on the sun is 15°. Boy, did I stick my neck out, opening up on this subject! Incidentally, I have my possible stars plotted on a mooring board before taking sights so that I can pick low altitude stars on desired bearings quickly; to help me locate them knowing course and zigzag plan; and to give me a picture of my cut as I take sights.
Position by observation of mountain peaks.—Nicely tucked away in Bowditch (Table 10) is a very handy little trick. With mountain peaks in view you can get a good position by bearing and sextant altitude. It comes in handy oftener than you might think, yet very few navigators are aware of its existence or value. I have found it extremely valuable on making a landfall.
Scale for reading time direct.—Many times, when piloting, sortieing, etc., the navigator is called upon to check time of runs, or time to points. This involves picking off distances and then converting these distances to time. The new nautical slide rule issued by Bu- Ships (Contract No. NXss-60767) is of great assistance, and is indispensable to the navigator. However, in the situation described above, a scale which reads time directly without the necessity of going through the distance step can be quickly constructed on graph paper.
Use any graph paper or a ruled pad. I prefer the same graph paper I use for plotting sights, since it is divided for easy reading of time.
Set your compass at approximately the height of your graph paper. Go to your chart and reset your compass at an even number of miles slightly less than the previous setting. Come back to your graph paper and strike your arc centered on a vertical line on the left-hand bottom corner of the page. Using your circular slide rule compute time necessary to run the distance of your arc, select appropriate subdivisions so that time fits, and label your time scale along the bottom of your graph. From the time computed run up until you come to your are, and connect this point with the point where you centered your compass, extending your line to the top of the page. By placing your dividers between points on your chart, laying this distance off on your line on your graph, you read time directly. Changes of speed require but a moment to set up, since your arc is already drawn. For large changes in speed you may find it convenient to double or halve your time scale. That sounds rather involved, much to my surprise. Perhaps you’d better look at Fig. 2.
The arc was drawn a radius of 5 miles because 5 miles was a little less than the height of my graph. Other distances could have been used as well. My speed was 15 knots, so I chose a time scale to fit, and found the point on the arc where the time computed (15 knots, 5 miles) intersected, and drew my line. The 20-knot line is indicated. In using, set dividers at distance picked off from chart, and lay on measuring line. Suppose it hits at x. A glance gives you 16 minutes—and you did not go through first computing distance. It really saves time when you need it. Obviously, to get 10 knots, merely double your time scale and use the 20-knot measuring line.
Have you ever had to fold under your yard scale on an approach chart or anchoring chart? Or even all of your scales? Using the above principle you can quickly contruct any type of scale you might need. This scheme is illustrated in Fig. 3. Certainly Figs. 2 and 3 can be combined, and in practice would be, if you wanted both features at the same time. Notice that I used the vertical scale because I wanted a division in tenths for yardage instead of the twelfths which is more convenient for time.
The ball sextant.—Your ball sextant is not intended to replace your horizon sextant but to be used when no horizon is available, either day or night. By a little practice in its use you will be able to get excellent information at times when you need it.
Controlled, acceleration or deceleration.— My notebook contains one item in ship handling that I feel should be passed on to new navigators for consideration, since it is a constant problem while operating within a task group. In maneuvering board problems, the question of when to take off speed or increase speed is a nice one. You can try to find a point where you change from a maneuvering speed to guide speed in one change, and if you are really good, if the guide is exactly at speed, if the engine-room accelerates or decelerates exactly as expected, if the wind and sea do not change your rate, and a few more ifs, you will end up in position with zero relative speed just as you figured. A lot of ifs and a lot of embarrassment when you overshoot or jockey around for a long time.
I prefer to have more control over the situation by adding a small safety factor without materially increasing the over-all time. In fact, it is my belief that it usually ends up by saving time.
My scheme is as follows: I know that my ship accelerates or decelerates 1 knot in less than 200 yards. How much less is not too important, and it varies at different speeds. The difference is my safety factor. Using 200 yards per knot, take relative speed times 200 yards; that gives a point where I must make a speed change. I will speak in terms of deceleration, although the same is true of acceleration. It makes little difference how much is taken off at that point as long as relative speed is not dropped to zero. I use up to 5-knot increments when I have large relative speeds, dropping to smaller increments as I approach zero. When I change speed I immediately establish a new point (new relative speedX 200 yards) where I must further decelerate. Continue this process down to the point where there is 1 knot left to take off. Instead of taking off that last knot at 200 yards I carry it in to 125 yards, since that figure approximately represents my distance for 1 knot. As an example to explain the above, assume a relative speed of 10 knots
2,000 yards reduce to 7 knots relative speed
1,400 yards reduce to 5 knots relative speed
1,000 yards reduce to 2 knots relative speed
400 yards reduce to 1 knot relative speed
125 yards reduce to zero relative speed
Let’s take a look at what is happening. At 2,000 yards I am making good my 10 knots relative speed. My reduction to 7 knots is run up and I am actually down to that speed through the water at about 1,500 yards more or less, depending on my “ifs.” I ride at this speed into my 1,400-yard point where a further reduction is made. If the guide speed, for instance, is too great, I find it out by the slowness of my approach from about 1,000 yards to 400 yards. A slow guide speed becomes apparent by my fast approach at about this point. I can never slow much less than guide speed and get warning of a slow guide speed sufficiently in advance to correct it. I actually control my deceleration instead of letting a lot of variables take charge. It’s been working fine for me, and it’s a simple thumb rule for O.O.D.’s.
For relative speeds of greater than 10 knots I use 300 yards per knot for the excess, 400 over 15 knots; that is, first cut at 15 knots relative speed is (12X200) plus (5X300), or at 3,500 yards. Also at these speeds I never use increments of less than 5 knot cuts until I am down to the lesser relative speeds, so my first cut at 20 knots relative is always at 5,500 yards to 15 knots relative, 3,500 yards cut to 10 knots relative, and at 2,000 yards cut as illustrated above.
Tanker runs.—Probably the touchiest job at sea is coming alongside another ship. The navigator must be prepared with every aid he can get, including a plan that works. I believe everyone will agree that it is best if at all possible to make your run from almost directly astern. I like 2,000 yards. On my first run, getting there was easy—but the Captain wanted, and very right—to be on a line 50 yards to the left of astern, and to come up on this line in order to check the tanker course. I blithely picked up my parallel rulers and started to draw in my line. Fifty yards is such a small part of 2,000 yards that you can’t draw any such line on a standard mooring board and note variations from it with any accuracy. You just need more paper, and no amount of squirming is going to help you. I know, because I tried the latter course. We made the run like maw and me killed the b’ar—maw did it! I crawled back into the chart house (they make them doghouse size, so the navigator feels at home!) and set me down to figure out how to keep that from happening again. I had mooring boards blown up by the photographic shop to 2 feet square, scaled to have 100 yard circles out to 2,000 yards. My next run worked like a charm. I found that I could draw my line 50 yards to the left of the center, plot positions quickly, and know instantly any course changes necessary. This developed into a 30-inch maneuvering board mounted in plexiglass with a plexiglass arm scaled to 50 yards, and pivoted at the center. I heartily recommend it. You can put her alongside exactly 50 yards, 75 yards, or what do you want? every time, and tell if the tanker is as much as ½° off course before you get alongside.
Equipment.—The old saying about a workman being only as good as his tools is very applicable to the navigator. I have mentioned some equipment that impressed me in the above, but I have one particular phobia, and that is the bridge itself—the real workshop. There are a few principles which will do much to avoid confusion. First, find the best place for each function; CWO, Radar Plot, Chart Table, Talkers, etc., and then put them there, together with all the equipment they need, and all of the outlets they need. By providing seats, and insisting that personnel sit in them, you may depart from custom, but you avoid people wandering all over the bridge trailing telephone leads. You can see out your ports without telling three people to move, you can find your watch on a dark bridge, and when necessary personnel can stand watches for longer periods without fatigue. And while I’m on the subject of seats, if you adopt this principle you might as well make them soft to start with. After about three months of forgetting how tiring it was to stand, you’ll hear complaints about hard seats. Talk about wanting egg in your beer! You can do a lot with a little thought and the ship’s force. An amplifier in your 4 JW circuit, with volume control, is of immeasurable value. And now—light! A subject as touchy as a virgin! My first experience with a maneuvering board at night was enough to convince me that there must be some solution other than two flashlights—one in my hand, and one in a talker’s hand—neither pointing where I wanted to see, and lighting up the bridge like a photographic studio. I finally had a metal box made with vents similar to a light 'lock—the top [made of thick red plexiglass, five small light bulbs on the inside, one in the center and one towards each corner. The lights are rheostat controlled. I cut a hole in my chart table, and set the box in flush with the top. A mooring board just covers the plexiglass, and is secured with masking tape. Results are excellent, even lighting over the complete maneuvering board, instantly available. As with many other things, new uses were developed. The OOD immediately used it as his number one picture of the formation at night, to lay dispatches on to read, etc. The CWO’s immediately needed one built into their desk for shackle code, etc. I’ve used it to light my chart. Its uses, like months away from home, seem to go on and on forever.
If you haven’t tried it, you might get some masking tape to use in lieu of thumb tacks. I got awfully tired of running into thumb tacks with parallel rulers!
“Reldet Prorep port comcardiv—may be duty as operations officer.” Anybody have a copy of Admiral King’s “Naval Directive in the order form?” Here we go again! I hope that I have been able to pass on to you a little of what I have gained in my tour at the best job in the world to learn to be a skipper.