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By Commander John J. Becker, U. S. Navy
Editor’s Note: This is the first part of a two-part feature on shiphandling characteristics of the Oliver Hazard Perry-class guided-missile frigates. Part II will appear in the February Proceedings.
When I was commissioned in the late 1960s, the officers 1 served under had been at sea during World War 11, or they had trained under others who had. They were masters of the shiphandling art. The ships of the destroyer navy had grown only slightly as each new class was introduced. They were twin-screw, steam propelled, and very similar in their handling characteristics. An officer could spend an entire career with only a short learning curve at each new duty station. The result was a more or less standard way of shiphandling that, when combined with the immense experience of the conning officers, set a standard of excellence that is rarely equaled.
Now an officer is frequently required to handle several destroyer types— twin-screw destroyers, single-screw frigates, gas-turbine propulsion with controllable-pitch propellers, and steam propulsion with fixed-pitch propellers and auxiliary propulsion units (APUs).
The Oliver Hazard Perry (FFG-7)- class guided-missile frigates are the most numerous of any U. S. Navy ship class yet, but there is little published on this class’s shiphandling. The basic premise for handling the FFG-7 is simple: APUs to oppose the main engine and move the bow, rudder to control not only ship course but also lateral movement of the stem, and main engine to keep an effective flow across the rudder as well as move the ship.
Using the combination of engine, rudder, and APUs it is possible to recapture the shiphandling excellence that was the traditional hallmark of the destroyerman. The FFG is fairly forgiving once you understand the vector logic. You can usually be a little slow in making your decisions and still recover nicely. You will find your FFG to be a handy, responsive ship that is fun to handle. It really is the
sports car of the fleet.
The FFGs are a legacy of Admiral Elmo R. Zumwalt’s tenure as Chief of Naval Operations.1 The theory is you don’t need an Aegis cruiser for every destroyer mission and you can build two low-mix FFGs for the price of one high- mix Spruance (DD-963)-class destroyer (or five FFGs for one Arleigh Burke [DDG-51] Aegis destroyer)—but that’s politics and this is about shiphandling.
What low mix means to the FFG driver is that the designers said the hell with redundancy and gave you only one propeller shaft instead of two, one anchor instead of two, one boat . . . well, you get the picture. Unlike earlier singlescrew frigates, however, the FFG-7 has gas-turbine engines, a variable-pitch propeller, and APUs. Its handling characteristics are unique, and the combination of what you have to handle the ship with is unique.
Let’s start with an outboard profile. Standing on the bridge, your height of eye is 41 feet, the bull nose is 132 feet in
Table 1 Ship speed, shaft rpm and propeller pitch Single Engine Two Engines
Ship Speed | Shaft rpm | Prop Pitch |
| Ship Speed | Shaft rpm | Prop Pitch |
25 | 142 | + 23.5 | ahead flank | 29+ | 180 | +23.5 |
20 | 112 | + 23.5 | ahead full | 25 | 142 | +23.5 |
15 | 82 | +23.5 | ahead standard | 15 | 82 | +23.5 |
10 | 50 | +23.5 | ahead 2/3 | 10 | 52 | +23.5 |
7 | 37 | +23.5 |
| 7 | 46 | + 16.5 |
5 | 33 | + 15.0 | ahead 1/3 | 5 | 46 | + 10.0 |
0 | 44 | + 1.5 | stop | 0 | 56 | + 1.5 |
5 | 54 | -14.8 | back 1/3 | 5 | 54 | -14.8 |
10 | 83 | -14.8 | back 2/3 | 10 | 83 | -14.8 |
15 | 113 | -14.8 | back 2/3 | 15 | 113 | -14.8 |
front of you, and the stem is either 313 feet or 321 feet behind you depending on your FFG’s flight deck/stern design. Your ship has a 47-foot beam, and the deepest projection below the waterline is the screw. The screw is 10 feet 2 inches below the keel. The screw’s depth is a function of displacement—generally about 24‘/2 feet.
The Bridge: This area is designed to support the “minimum manning concept” (another low-mix legacy). The helmsman not only controls the rudder but also has direct control of the main engines and APUs. During restricted maneuvering conditions, a lee helmsman is assigned to operate the main engine programmed control lever.
This throttle, located on the helmsman’s right, controls both propeller pitch and engine speed through the processor in the central control station (CCS). The processor, when in the “programmed control” mode, adjusts the pitch and shaft revolutions per minute (rpm) to obtain the speed you have ordered on the throttle. Programmed control is the only way you will have control on the bridge. CCS can take control from the bridge for lighting off or securing engines or during a casualty. Changing the shaft rpm and/or the pitch will alter the ship’s speed. At lower speeds, the propeller’s pitch is the primary impetus to change: an increase in pitch increases the ship’s speed while rpm changes are minimal. Once maximum pitch is reached, all further speed increases are achieved by increasing shaft rpm. (See Table 1.)
Notice that shaft rpm drops slightly as pitch is applied in the ahead direction at low speeds. When there isn’t a lot of wind you can hear a change in the gas turbines on the bridge. This will let you know when your order is taking effect and is helpful when all you want to do is give the ship a little push. Notice also that full astern pitch is reached at back one- third. This is a major cause of greater stem walk while backing.
Where’s the Stern? Ever since the Navy got serious about putting helicopters on board destroyer-type ships, our superstructures have begun to look more and more like big boxes. At the same time, the hulls have been getting longer and longer, but the bridge wings have stayed about the same—they don’t extend over the side and the net result is poor or nonexistent visibility aft.
This is particularly troublesome when mooring in a situation with little clearance astern. Most ships rely on the fantail line-handling party to keep them advised. In the best of circumstances, all one gets is a “guesstimate” by someone claiming to have “seaman’s eye.” Some ships put out flags on horizontal poles that can be seen from the bridge.
My local harbor pilot in Mayport, Captain Tom Reynolds, told me the flags reminded him of training wheels and passed along the following method for telling where the stem is:
Stand on the bridge wing from where you normally conn the ship alongside. Have someone place a life ring in the water, positioning it even with the aftermost part of the stem, but far enough from the side so you can see it from the bridge. As you look at the life ring, try to sight some object on the side of the ship that is in line with the ring. On my ship I painted a small white band around a deck drain pipe just forward of the hangar. It was seven feet four inches from the main deck to the mark. On your ship, it may be the top of a handrail or a vent.
Once you’ve identified or painted your mark, anything below your line of sight to the mark is forward of the stem and therefore a danger. Anything above your line of sight is clear of the stem.
Main Engines: The engines are General Electric LM2500 gas turbines. Although they are capable of 25,000 horsepower, they are regulated by speed- and torque-limiting circuits in the engine- control computer to 20,500 shaft horsepower each. If that doesn’t impress your friends, tell them you have the seagoing version of the TF-39 engine used in the DC-10 airliner and the Air Force C-5A Galaxy.
The jet engine part of the LM2500s, called the “gas generator,” has no direct mechanical link with the reduction gear or propeller shaft. Power is produced by putting another turbine wheel, called the “power turbine,” in the exhaust of the gas-generator section of the LM2500. This is called “air coupling.” It’s possible to run the gas turbine without turning over the reduction gear or shaft. We do this by engaging the shaft brake.
Shaft Brake: Use of this brake is governed by a set of important rules:
- Before engaging the shaft brake, tell CCS so they can pass the word for people in the main engine room to stand clear. The brakes have, on occasion, thrown various pieces around the engine room after coming apart.
- Don’t leave the brake engaged for more than 14 minutes.2
- Don’t use the shaft brake more than six times in one hour; this will prevent excessive heat buildup.3
Sounds easy, doesn’t it? But hold on— you’re not ready for your surface warfare officer (SWO) board until you can list in proper “GITMO” fashion the requirements for the brake to engage. They are:
- Shaft at idle, below 75 rpm.
- Throttle at stop position.
- Pitch at zero.
- Control must be at the station engaging the brake.
In other words: You’ve got control on the bridge and want to engage the brake. You must bring the throttle back to the stop position and it must be in the detent; otherwise, the brake won’t engage.
While this may sound like SWO trivia, the shaft brake is one tool you have in your ditty bag to fight the awesome “Stemwalk Monster.”
Clutch: The power turbines are coupled to the reduction gear using a synchronized self-shifting (that’s triple s to snipes) clutch. Here you’ve really got the Spruances beat—no air bags or failed operational propulsion plant examinations (OPPEs) owing to clutch problems. The triple ,v clutch is a simple reliable system that automatically engages or disengages the gas-turbine engjnes as they come on the line or are secured.
Table 2 APU Head/Tail Boundary Restrictions Head to Head Port APU betw.een 060 and 120 and starboard 240 to 300
Tail to Tail Port APU between 240 and 300 and starboard 060 to 120
Head to Tail Port APU between 060 and 120 and starboard 060 to 120
or
Port APU between 240 and 300 and starboard 240 to 300
Propeller: Once the clutch engages, the reduction gear turns and power is transmitted to the controllable-pitch propeller (CPP to FFG handlers, not to be confused with the controllable reverse pitch—CRP—propeller on the Spru- ance). The CPP is \6'A feet in diameter and creates the Stemwalk Monster.
APUs: What makes FFGs unique among U. S. Navy surface combatants is the addition of two retractable APUs installed side by side directly underneath the bridge. They were designed to get the ship back to port after a main engine casualty, but are used for all low-speed shiphandling evolutions. The APUs are constant-speed, 325-horsepower electric motors driving a 36-inch propeller. This is an important point: you can’t adjust their speed. What you can do, however, is change their direction. By doing this you change the force exerted on the ship in the ahead/astem direction and the port/ starboard direction. The APUs are positioned using relative train orders with the ordered bearing being the direction in which you want the APU to push.
Some APU Rules:
- Ship speed must be below five knots for raising or lowering, or for operating the APUs.4
- Flave three ship service diesel generators (SSDGs) on the line.
- Do not exceed three starts in rapid succession or six starts per minute with less than a five-second off period between starts.5
- Don’t start both APUs together.
- Never operate both APUs.6
- Don’t train an operating APU in the wake of another operating APU. The wake boundaries are defined in the Tail- to-Tail and the Head-to-Tail rules (see Figure 2).7
Some APU Suggestions: Use the APUs in tandem. A lot of people like to put one APU athwartships (090 or 270) and one at 180. This has been called the APU power makeup and works adequately in some situations, usually at the beginning or end of a mooring evolution. Once you start changing APU directions and are keeping both of them energized, however, it’s easy to get confused. You’re trying to keep track of enough things as it is. Give yourself a break—for most evolutions keep both APUs trained in the same direction. If you want to move the bow to port or starboard you will get more of a push with both APUs at 240 or 120 than with one at 270 or 090. For those who don’t believe me, calculate the cosine of 30 degrees times 2 (APUs) times 325 (horsepower). My calculator gets 563 horsepower push to the side.
Using both APUs together also gives you more flexibility in maneuvering the ship. Your FFG will almost never move exactly according to your initial game plan. When you’ve got your APUs in the APU power makeup position you’ve lost the ability to make fine adjustments to the movement of the bow. All you can do is start and stop the athwartship APU. With both APUs you can make small changes to the bow by training them. The same
applies to using the APU at 180. You can only use 325 horsepower’s worth of your main engine without getting headway, but by using two APUs and changing the APU train you can not only make incremental fore and aft adjustments, you can also use more main engine power, which will in turn give you greater control of the stem by using the rudder. (See Figure 3.)
Notice that with both APUs at 150/210 you get a side vector equal to one APU at 090/270 (the same as APU power makeup), but you get a larger astern vector. Now you can use a larger engine- ahead vector to control the stern. For this reason, APUs at 150 is a good starting point to crab to starboard. To crab to port you will want to use more engine and rudder power to overcome the starboard stem walk, so a 200 train for both APUs is a good starting position. Because of the larger astern vector from the APUs, you can use a 3‘/2-4-knot ahead bell without getting headway.
Some APU Reminders:
- Remember the APU locations—below the bridge (frame 100) just forward of the pivot point. The APUs not only push the bow, they also tend to move the entire ship. You can’t twist the ship by pointing one APU ahead and one astern.
- It takes time to raise and lower APUs. In making a landing you must plan ahead on when to slow the ship below 5 knots, and then allow about 2'A minutes to lower the APUs.
- Both APUs operated at 180 will require about 4'/2 knots ahead on the main engine to keep the ship dead in the water.
- The Heads or Tails rule applies only when both APUs are energized.
- APUs can be trained while they are energized as long as you don’t violate the wake rule.
Other Factors:
- A lot of sail area. FFGs are very sensitive to the wind. Even a 5-knot cross wind will cause a noticeable set. It’s time to call the tugs if you have an unfavorable wind of more than about 12 knots. Remember the hangar doors during shiphandling evolutions. Open hangars tend to catch any wind from astern and push the stern accordingly. This has occasionally been used as an assist by some sharp FFG handlers. When CCS totally loses it (i.e. experiences main propulsion casualty), an FFG will lie broadside to the wind.
- Thin skin. FFGs (we’re low mix, remember) have thin hull plating—as thin as 3/8-inch amidships. You may get to leave your FFG with a permanent record of your shiphandling expertise, while your buddies on other ship classes can paint over their mistakes. Watch out for the masker belts, and also for the replenishment outriggers.
► A pivot point slightly abaft the bridge. You can’t be too precise here. Is it under the combined antenna system (CAS)? In the charthouse? Just assume it’s between you and the SPS-49 air search radar platform. Leave the jackstaff up during sea detail so you have a quick reference of the bow falling off to one side or the other, but remember—you have a football field behind you that will move to the side from a pivot point only slightly astern of your conning position on the bridge. Experienced shiphandlers, regardless of ship class, always watch the stem for early indications of the ship twisting around the pivot point. The 35- foot whip antennae on the back of an FFG’s 02 level are excellent reference points. One note of caution: when using APUs, the pivot point will move aft, depending upon the trained position of the APUs.
► A 6,000-pound anchor and 13 shots (1,170 feet) of a IVs-inch chain. Low mix here means only one anchor. The hawse is located on the starboard bow.
Table 3 Sample Conning Orders Right full rudder Engine ahead standard Indicate 12 knots Train port APU to 120 Start port APU Port APU is trained to 120 and on, Sir
Train port and starboard APUs to 180
Port and starboard APUs are trained to 180 and off, Sir Train APUs head to head
Port APU is 090 and off,
starboard APU is 270 and off, Sir
- Standard destroyer mooring lines. Lines one and six are six inches and are used as breast lines, to control lateral movement of the ship. Lines two, three, four, and five are five-inch lines and are used as spring lines, to control fore and aft movement. Lines two and four check headway and lines three and five check stem way.
- A warping capstan aft and an anchor windlass forward. The anchor windlass is fitted with a gypsyhead for handling lines. The gypsyhead and the capstan are usually used with the breast lines in mooring evolutions.
- A keel-mounted rubber sonar dome. The dome is 20 feet aft of the anchor hawsepipe.
- Helo safety nets mounted outboard of the hull. A lot of shore intermediate maintenance activity sailors have made a career of repairing the fiberglass net frames. Whether yours are aluminum or fiberglass, you can easily decertify your flight deck with a misplaced tug or a sloppy landing.
- Sharp sides. No, we’re not talking about your paint job. We’re talking about the angle between the side and the main deck. This is particularly important when mooring alongside another FFG. Returning from sea you will usually be riding higher than your sister ships, which is a perfect way to make an impression. The areas below the bridge wing and the hangar sides are the most vulnerable. Hand-tended fenders are essential here.
If your FFG is going to be held off the pier or another ship with camels, the camels need to be placed between the masker belts. This is the only place where the sides stay vertical for any depth below the waterline. If the camel is fore or aft of the masker belts, your FFG may ride up and over the camel because the slope of the hull.
“Different ships, different long splices,” is the old saying. Just as there are many ways to handle an FFG, there are also different ways to give conning orders. Find out what’s in style on your ship before your first watch.
Engine Orders: Some differences include giving engine orders in feet of pitch for low-speed maneuvering or giving engine orders in shaft rpm when alongside other ships for underway-replenishment (UnRep) operations. One variation on the second case is giving CCS engine control because they can read shaft speed to single rpm’s. The bridge dial indicator can only read to the nearest five rpm’s. I think all of these methods are unnecessary. Keep throttle control on the bridge and give engine orders in terms of knots or half knots. Even alongside during UnReps, half-knot engine orders will keep you on station without difficulty. Phrases like “ahead easy” are fine when talking to your tugmaster, but are imprecise to your bridge crew and should not be used.
APU Orders: APUs are another area of difference. Some ships call them thrusters, some “start” the APUs and some “energize” them. I prefer “start” only because that has been a standard command in the engineering world and APUs are not thrusters, as any ex-tank landing ship driver will tell you. Because the “head-to-head” configuration is often a convenient way to leave the APUs when making fine adjustments to the bow, the order “train the APUs head to head” can be used as a standard command. Remember the rule against having both APUs energized while head to head. The helmsman should always respond to a completed APU order with whether the APUs are “on” or “off.”
Rudder Orders: Chalk one up for tradition, mates! If you can overlook that poor excuse for a wheel on the ship control console, you can give the same standard rudder orders your great-grandpappy gave in the Big One. As with all destroyer types, standard rudder is 15°, full rudder is 30°, and hard rudder is 35°.
Sample Orders: Table 3 lists some recommended conning orders for an FFG. They are not all-inclusive. They should be considered a supplement to the Watch Officers Guide. For the sake of clarity, orders will be indicated in bold type and responses in italic.
'Adm. Elmo R. Zumwalt. Jr., USN (Ret.), On Watch (New York: Quadrangle/New York Times Book Co., 1976), pp. 72-75.
2Navsea Tech Manual, S9234-AD-MMO-010/ LM2500, Vol. I Pt. I, p. 3.2.
3FFG-7 Class Advisory 15/84, Commander Naval Sea Systems Command message, 061542z March 1984.
4NavSea Tech Manual 0963-LP-047 Retractable Auxiliary Propulsion System, pp. 2-11.
5Ibid., pp. 2-12.
6NavScaTech Manual, Retractable Auxiliary Propulsion System, pp. 2-12.
7FFG-7 Class Advisory 38/80, revision one, APU Train Motor Overcurrent, Commander Naval Sea Systems Command message 082026Z January 1986.
A winner of the Junior Officer Shiphandling Competition as a lieutenant, Commander Becker has served on a variety of destroyers, frigates, an amphibious ship, and on Swift boats in Vietnam. He commanded the USS Antrim (FFG 20) from January 1986 until March 1988. Commander Becker is currently the surface operations officer for Carrier Group Six.
The USS Ingraham Last of the Breed, First of a Kind
By Commander Richard H. Purnell, U. S. Naval Reserve
The USS Ingraham (FFG-61), commissioned 5 August 1989, is the 51st and final USS Oliver Hazard Perry (FFG-7)- class ship delivered to the U. S. Navy. The Ingraham was constructed at the Todd Shipyard in San Pedro, California. Combat system integration was accomplished by Unisys Corporation, Defense Systems, primarily at the FFG-7 Combat System Test Center (CSTC) in
Ronkonkoma, New York. The U. S. Navy FFG-7 ship construction program will end after almost two decades when Ingraham completes her post shakedown availability in early 1990.
Combat system development work for the USS Oliver Hazard Perry (FFG-7) began in 1972 at the Sperry (now Unisys) land-based test site in New York, which featured a physical mock-up of the combat system, including a functional combat information center (CIC), equipment rooms, and live radars. Weapon system simulators and a dedicated simulation support program provided realistic FFG-7 combat environments for CIC operations.
Development progressed through four baselines using the Combat System Test Center as a working laboratory before the Navy approved the final Oliver Hazard