When in the course of so-called “deep draft” qualification you find you have orders to command a fleet oiler instead of the cruiser you had in mind, don’t be downhearted. In the first place, command, per se, is the most rewarding experience that the Navy has to offer, and, secondly, you are on the eve of a quite worthwhile and entertaining experience and one that will probably make you a better seaman.
In the Atlantic Fleet, oiler operations extend to the limit of naval operations and include in-and-out operations from East Coast home ports, Norfolk and Newport, as well as extended deployments to the Mediterranean. Two oilers (white) are home-ported in Barcelona where their jet and prop-propelling cargo can be made readily available to the sensitive requirements of the Sixth Fleet. The oiler training cycle is a two-year one so that a three-months’ overhaul with subsequent refresher period takes a periodic bite out of fleet operations. Special projects often occupy the AO-143 Class due to their versatile potential. Neosho was actually fitted with an underwater torpedo tube for experimental firings off Newport this past summer—an unique first in the oiler field.
Design Characteristics
The Navy operates two classes of fleet oilers in its two geographical Fleets—the AO-143 Class, of which there are six in commission, three in each Fleet, and the AO-22 Class, of which there are a great many more. The former with their 656-foot length, 86§-foot beam, 35-foot loaded draft and 38,200-ton fully-loaded displacement, are about 100 feet longer than the latter and comparably larger in related characteristics. The AO-143 Class with a 20-knot sustained speed has a two-knot margin on the AO-22 Class. Also, with some forty per cent greater rudder area, there is a corresponding improvement in maneuverability. However, in discussing shiphandling and maneuverability, both classes are so far removed from their average captain’s previous area of experience that there is no significant difference between them except in detail, as one would expect from size, speed, and rudder characteristics. Carrying roughly 222,000 barrels of fuel in cargo tanks and bunkers, the AO-143 Class is comparable in size to the smaller of present-day commercial “supertankers.” To give some idea of the size of these behemoths, “supertankers” are built and building today with a cargo fuel capacity of 620,000 barrels. But, of course, their problems are inherently different—and they are only tankers.
Shiphandling Characteristics
Fleet oilers are large ships with low power (about a half, in the AO-143 Class, to a quarter, in the AO-22 Class, of that of a destroyer) and deep draft, and that is the first fact that must be indelibly impressed on the mind of a prospective captain. They are basically merchant types, not designed with a view to ever-present naval operating requirements, hence good for steady steaming and relatively poor in the maneuverability desired in going alongside other ships and in frequent operations in busy harbors and alongside piers, sometimes without assistance. In their various degrees of loading, they become quite different ships. The degree of loading is a variable that must be applied in the successful formula for any operations.
Generally speaking, the use of pilots and tugs is highly recommended, the former for knowledge of local conditions and the latter as a necessary adjunct to slow-speed maneuverability—or lack thereof. Except for areas, such as the Norfolk Naval Base, where pilots frequently handle oilers, it is wise to have the pilot’s shiphandling desires pass through the captain, who can translate to the helm and engines what he knows can be done. An excellent case in point is a recent passage by Neosho in the Piscataqua River to the Portsmouth Naval Shipyard. Here the pilot’s intimate knowledge of the varied and tricky currents in that river is essential, but just as much so is the captain’s knowledge, not necessarily held by the pilot, of how to get the ship action desired. The use of pilots and tugs has an added advantage in teaching the captain, if he does not already know (most don’t) how to use tugs effectively and the signals to get the desired action from them. This is a most interesting business and may come to be quite useful where there may be tugs but no pilot. Of course, it is all the captain’s responsibility, anyway.
One of the first things you are going to notice on the bridge is the absence of the excellent vision ahead that you recall in a combatant ship. You are looking through a forest of masts, booms, rigging, and gun mounts. This must be accepted, and the only solution is to move about if you want to see. There is ample room to move and a good deal of exercise to be obtained in dashing the 86 feet from wing to wing of the bridge. This in turn poses another problem. When you are so far off the centerline, the jackstaff can’t be used as being dead ahead. Accommodation of this situation can be greatly assisted by the installation of white lines or sighting means on the forward bridge shield that line up equally off- centerline with similar lines or means, visible from the bridge, on some part of the ship’s superstructure forward of the bridge. This then will orient the perspective of what is dead ahead when you are on the bridge wing where ahead vision is better.
During any operations in restricted water, to piers or anchorages, one must constantly keep in mind the absolute necessity for deliberate and thoroughly anticipated action. This type ship naturally acquires considerable momentum when underway and, likewise, gains way very slowly when stopped. Consequently, vigorous means must be used to gain way from conditions of no way on, and, correspondingly, way must be removed early and positively when approaching a desired stopping point. At slow speeds a loaded oiler is extremely difficult to handle. Wind and current add further complexity to the problem. Any alteration to course requires substantial (at least 20° rudder and/or § engine) initiation, followed by judicious relaxation just as the desired effect is commencing. Even when up to speed, particularly in following a channel, it is best to initiate a turn with large rudder angle, quickly eased as the ship’s head starts to swing. Small rudder angles, successively applied, are slow to start a turn and difficult to stop when the cumulative effect has been felt. In the light condition, this factor is not so significant from the point of view of angular momentum due to rudder.
Current has an expected but augmented effect. With up to 35 feet of hull under water, it is not surprising that it takes at least four tugs (YTB size) to handle a loaded AO-143 Class ship against an average current (1-2 knots). As the draft decreases, the relative effect of current and wind vary oppositely. The other extreme is reached with the ship empty of cargo fuel (a few feet at the bow and 28 feet aft). Here the wind is preponderant due to the large sail area of the bow. Interestingly, once the ship is twisting with engines and tugs in this condition she is most difficult to stop due to the effect of wind and the relative lack of water resistance at the bow. A remarkably high and somewhat disturbing angular velocity is achieved that will take engines as well as tugs to stop. At normal loading the sail area aft (augmented by the large stack) is the governing factor in the prediction of wind effect. As the load decreases this becomes less effective until, as noted above, the bow becomes the sail in the extreme light condition.
Typical Evolutions
Anchoring: With the ship approaching an anchorage, it is difficult to maintain heading, at the same time slowing to have little or no way on at the drop point. Here again the engines must be used to twist as necessary and in the degree required. Ascertain which way the bow will fall off, then a judicious lead angle on course, when there is still adequate way on to steer consistent with the obstacles in the harbor, will be effective. It is desirable to be dead in the water at the drop point. A little sternway produced thereafter will rouse out the chain. Under average conditions of weather and load and the ship at ten knots, slow to one-third at 1,500 yards distance, stop at 1,000 yards, and commence backing (one- third or two-thirds depending on way on) at 500 yards. It won’t remind you of a dashing anchoring in a destroyer, but you’ll drop the hook in the assigned berth the first time.
While at anchor, with wind or current not a factor, oilers ride quite well to a scope of chain seven times the depth. But if either wind or current are of significant effect and different direction, the ship may be on an entirely different heading to that of other ships, with the chain tending at one, two, or three o’clock. From this, two facts to give caution emerge. Don’t anchor too close to other ships expecting that all will tail in the same direction. When the chain tends as above, it and the anchor will be under more than normal strain; hence it would be wise to use more than the normal scope, or about ten times depth.
In casting, upon leaving an anchorage or mooring, it may be desirable to back away if sufficient water is not available to cast safely in place. When the wind is light, this can be done until sufficient room is found to come to the desired course. Or the ship may be cast with the anchor still down, holding or dragging, to restrict the area required for the maneuver. In any event, in casting it has been found necessary to use the maximum twisting moment to complete the maneuver in a reasonable time for a change of ship’s head of marked degree. If there is room to get some way on (even sternway) prior to the application of maximum twisting force, the rudder may be used to significant effect and the cast benefited greatly thereby. Even with all these choices, there are times and conditions when an apparently good cast ends up “in irons.” This has been a very difficult problem at times in Neosho.
Mooring to a Buoy: In mooring to a buoy the approach is subject to the same wind, current, and non-maneuverability at slow speed that affect the approach to an anchorage. A compromise course must be selected, depending on load and effect of wind and current, to end up in reasonable proximity to the buoy. Last-minute backing and filling is next to impossible to do effectively, and a new approach is a time-consuming and difficult alternative. Here the boat in the water should be prepared to essay a considerable distance with the first line to the buoy. This can retrieve an apparently very hopeless situation. An ever present difficulty in the final moments of a good approach will be losing sight of the buoy from the bridge since the conning officer’s view is obstructed by the flare of the bow and the forward gun tubs. It is most helpful to have a responsible officer on the forecastle to conn the ship during the last 150 feet or so of the approach. The captain can still supervise from the bridge and interject any orders he feels are required.
Replenishment at Sea: The fueling of a task group at sea is the raison d’ètre of this type of ship. It is an operation that requires of the oiler the following: (1) be at the specified rendezvous position on time (in advance); (2) take prompt and accurate position, course, and speed as directed by the OTC; (3) be ready to send gear over to first ships alongside and start pumping at first opportunity; all to be accomplished with maximum expedition; (4) maintain a steady course and speed as guide for alongside ships; (5) maintain maximum pumping pressure that can be accommodated by each ship alongside; (6) act as central transfer point for task group ships; (7) supply bottled gas and drummed lubricants as requested; (8) deliver mail, personnel, and any supplies aboard destined for task group; and (9) be constantly alert to take immediate action to alleviate any emergency that may arise due to ship-handling errors or casualties in ships alongside—or in own ship. Normally destroyers are taken on the oiler’s starboard side while heavies—carriers, cruisers, and large auxiliaries—are taken on the port side. Destroyers may also be fueled to port by attaching a “pigtail” (a short length of 4" hose) to the end of the 7" hose. Neosho and Truckee of the AO-143 Class have had certain modifications made in connection with a special project that cannot help but augment their usefulness in TG replenishment. A helicopter platform has been installed aft of the stack* making available all the advantages of the versatile helicopter and some 1,650 cubic feet of reefer spaces is now contained in the forward hold of this class.
In calm or light seas and winds, the fueling course and speed are not too significant. If a course must be selected where yaw becomes a factor at all, more speed should be used, say twelve to fourteen knots to assist steering. When the seas are ahead and steering is not so difficult, nine or ten knots would be easier on personnel on deck. Of course, if the tactical situation, steering difficulty, or other reason requires, higher speeds than ten or twelve knots may be used. The author has fueled in a destroyer at eighteen knots in moderate weather. To show what can be done if required Neosho and Forrestal recently conducted a token refueling at 20 knots for an hour. Sea was State 3 and the operation was continued for about an hour. Neosho was guide and no particular difficulty was encountered unless Forrestal closed to within 140 feet separation. When this latter occurred, steering was made quite difficult (excessive corrective rudder angle) in the oiler due to the carrier’s bow wave pushing the oiler’s bow away. As speed increases to this range, greater distances should be kept between ships. In heavier weather for normal speeds the wind (and sea) should be brought one to two points on the port bow. This will provide a lee for small ships and facilitate handling the carriers. If wind and sea are marked and from different directions, a decision must be based on relative effects. If sea conditions are rough, fueling down wind is frequently desirable for the safety or comfort of personnel in small ships. If the oiler yaws, this is not feasible; but if not, it is questionable whether the destroyer will. A rule states that if the length of the swell is one quarter or less than that of the destroyer, the yaw will not be markedly deleterious to the operation. If in any doubt, the destroyer can always take a comfortable position at double distance from the oiler to check the conditions on the spot. Then proceed as judgment dictates.
When a large ship comes alongside an oiler there is a screw and water inter-action between them that momentarily slows the oiler and temporarily throws her off course, stern to the other ship. This, when anticipated, can be quickly neutralized and the ships will avert an unnecessary hazard. The opposite effect is experienced upon leaving.
After the fueling has commenced, it is incumbent on the oiler, although guide for the operation in most cases, to be ready for any conning action required to minimize a situation where the receiving ship is temporarily in a hazardous position due to casualty or conning error. The extent of what can be done is, of course, dependent upon how many ships are alongside and their positions. But the oiler OOD and CO can often taken action of this nature and must feel no restraint in doing so. If the action can be taken that will keep the ships parallel, it will be a boon to the situation. But it must be fast and correct! In this connection, many hazardous situations are created by ships trying to ride too close in the belief that this is a manifestation of expert shiphandling. In general, except for a specific reason, such as a necessary shortening of high- line, etc., it is not. The time to be in close is during the passing of the gear. After that evolution is completed the receiving ship should ride out at approximately twice the distance held during connecting up. The optimum distance for passing the gear and connecting up is fifty feet for destroyers and a hundred feet for large combatants, if sea conditions will permit.
Turning or altering speed in a fueling group is a relatively simple matter. Bridge-to-bridge telephone communication is necessary between the conning officers. With large ships ½ to 1 knot can be accommodated. The oiler should make the change first and immediately announce it to the other ship. Destroyers can handle two-knot changes, or more if required. Again with larger ships, course changes in increments of five degrees are quite feasible. During this maneuver the position of the receiving ship should be observed carefully and constantly to insure that a developing hazardous condition is quickly recognized and corrected within the means available to the oiler conning officer. Stopping the turn until conditions stabilize will usually be effective. Destroyer types can be turned five to ten degrees at a time under good conditions and frequently when the turn is proceeding smoothly, a small, constant rudder angle on the oiler can result in a continuous turn-together. If not turning smoothly together, the turn should be stopped, ships steadied up on the same course, and approximate position alongside regained before continuing the turn. During all these maneuvers the oiler conning officer must continuously announce on the bridge-to-bridge telephone to the other conning officer what is being done; e.g., his successive headings, how much rudder (relatively) is being used, and when his rudder is being changed or reversed to steady up. The key to success is co-operation between conning officers, backed up by a keen and constant observation of the instant situation.
Formation: For steady steaming oilers give no particular problems in stationkeeping in formation. However, their inherent resistance to turn (inertia) must be quickly overcome by large rudder angle, use of engines (at slow speeds) or both.
Consolidation: While it is customary for other ships to make the approach and come alongside oilers, it is not infrequently necessary for the oiler to go alongside a provision ship, an ammunition ship, or another oiler to shift cargo or consolidate (pool remaining cargo in one oiler). Then the light oiler can proceed to port to reload. At one time oilers were going alongside Midway-class carriers. When this evolution is required, all that has been said before on maneuverability applies. There are some other rules that can be most useful. One is the rule of 60 (a sine table in one’s head) good within one per cent up to 45°. The rule, stated simply, is that each degree of arc is one- sixtieth of the range. Thus, in making an approach, at 1,200 yards, if the difference in ship’s head (base course) and the bearing of the near bridge of the ship being approached is two degrees and course is maintained, the approaching ship would be on a track 2/60 X 1,200 = forty yards or 120 feet laterally displaced from that of the ship being approached. The surge figure of an AO-22 Class oiler is considered to be seventy yards per knot loaded and about sixty yards when light. This figure for the AO-143 Class is considerably higher and, when loaded, is close to 110 yards per knot, varying, perhaps, to about ninety yards when light. This means that the approaching ship will advance this many yards per knot of overspeed on the ship being approached during deceleration to base speed. If you have slowed too soon, add speed generously, or you will hang interminably on the quarter. But, be sure to take it off at the first sign of forward movement. If you ride past on the approach, a preferable error since lines may be handled all the while if not too far forward, takes off turns liberally; but be prepared to take base speed as soon as any relative motion aft is detected. Once in position, changes of one degree and one to two turns are usually ample to maintain position. Oilers can consolidate in this fashion with surprising disregard for wind and sea. It is helpful and safer to put the light oiler downwind in a beam wind so that they will tend to drift apart rather than together. In clearing, use plenty of speed, within available limits, and by small, successive changes of course open until the positions are such that the stern is clear for a radical turn away.
Conclusion
It is hoped that these discussions of that exciting and always interesting art of shiphandling, in a somewhat different league from that in which most of our experiences have been, will be instructive and useful on the job. Nothing which has been written is intended to indicate that the necessary capability cannot be quickly acquired by any one well versed in the basic principles of seamanship and handling ships. Many have. These thoughts should supply an effective and, perhaps, provocative headstart.
*This has recently been accomplished in the Mississinewa.