1. Overview
Chapter 5 covers the docking itself — the final act of bringing the ship alongside. The chapter opens with a long bridge conversation praising the permanent, unit-trained crew: mates, engineers, and most of the unlicensed crew who rotate as a team, know the ship and each other, and work without endless radio chatter. A crew kept together as a unit takes pride in the ship and makes shiphandling and docking safer and more efficient — a point the author returns to throughout the book.
The technical heart of the chapter is a single principle: use finesse, not force. A ship is a large, moving mass brought against an unforgiving, immovable pier; the accomplished shiphandler does not "drive" or "belt" her into the berth but eases her alongside, working with wind, current, and quickwater rather than against them.
2. Using Wind and Current to Advantage
Too often the seaman treats wind and current as hindrances to overcome, rather than as aids to be used with rudder, engine, tugs, and anchor. A powerful tug can fight a moderate wind or current — though the docking will be sloppy — but even the finest tugs cannot fight a strong wind or current, nor should they be asked to. Before docking, get out on the wing and feel the wind on your face; constant awareness of wind, weather, and current is essential.
2.1 The 30-to-1 Ratio
How do wind and current compare? Air is about 900 times less dense than water, so for a given velocity wind has far less effect than current. Both effects vary as the square of the velocity, through the pressure relationship:
where P = resultant pressure, ρ = density of the fluid (air or water), V = velocity of the fluid, and g = acceleration due to gravity (32.2 ft/sec²).
The practical result: a 30-knot wind exerts the same force on an equal area as a 1-knot current. This 30-to-1 ratio shifts with superstructure area, draft-to-freeboard ratio, and trim, and is not a formula to apply to every docking — but it is a useful base for judging the relative effect of wind and current. As the ship slows, her momentum and the effect of rudder and engine fall while wind and current stay the same; when dead in the water, only wind and current act on her. A well-planned docking positions the ship so that as these forces "take charge" they assist the berthing.
2.2 Working With the Wind
| Situation | How wind or current assists |
|---|---|
| Wind blowing off the berth | Used to overcome the ship's lateral motion toward the berth, instead of tugs and engine. |
| Wind blowing on the berth | Eases the ship alongside if she is stopped a few feet off the berth. |
| Current across the end of the berth (on the quarter) | Assists turning into a slip; the ship is landed and pivoted on a camel or piling cluster rather than steamed in against the current. |
To work with an offsetting wind, take a greater angle to the berth and deliberately give the ship more lateral motion as she comes alongside: kick the engine ahead with rudder hard over to move the stern toward the berth, then hold her alongside with tugs. The larger angle compensates for the wind while the ship has headway; as she slows, the lateral motion overcomes the wind. In stronger winds, drop an anchor to check the bow and amplify the lateral motion. With a strong wind on the berth, put the ship alongside earlier and let her slide up the stringpiece into position — she cannot be blown heavily against the dock if she is already alongside.
3. Measuring Slow Rates of Speed
The minimal speeds used while docking can be measured without instruments by one rule of thumb: a ship moves 100 feet per minute at 1 knot. If in doubt, note the time and the ship's position relative to a bollard, then note it again after a convenient interval — the speed is immediately known. Distances between bollards can be estimated by comparing them with the ship's beam; a ship moving between bollards 150 feet apart in one minute is making 1.5 knots.
Do not ignore the obvious: engine revolutions equate to speed through the water. This is so obvious it is often forgotten near a pier, yet RPM is nearly as good an indication of speed at low revolutions as at sea. Learn the ship's RPM-to-speed ratio — if 10 revolutions equals 2 knots, then 60 revolutions equals 12 knots — and a detailed table need not be consulted continuously.
4. Detecting Lateral Motion
Allowing for wind and current soon becomes second nature, but the shiphandler must also develop an eye for the less obvious lateral motion — the sideways slide through the water that occurs even when the ship makes no headway. Three actions cause it.
| # | Source of lateral motion (independent of wind and current) |
|---|---|
| 1 | Turning as the ship approaches the berth. |
| 2 | Extended use of tugs. |
| 3 | Checking or holding the lines before the ship is alongside. |
Unchecked, this motion carries the ship toward or away from the berth, or lands her with excessive force. Lateral motion is not only an effect to avoid — at times it is desirable, a factor to watch for and use to advantage. It is easiest to detect from the centerline, where the view of the ship and her heading is best: watch objects ashore ahead or astern and use their change in alignment as a range, noting when the distance from the pier changes independent of heading, wind, and current. Detecting and using this sideward slide is a mark of an accomplished shiphandler — it is the effect least appreciated by the inexperienced.
5. Setting Up to Back
Before going astern — especially when docking without a tug aft — a single-screw ship with a right-hand turning propeller should be set up so her inherent twisting effect helps rather than hinders. Because the approach is planned to allow for this twist, only one extra maneuver is needed. Note throughout that near the berth the rudder is used to move the stern, not to change the ship's heading, so its effect on each end must be considered separately.
5.1 Starboard Side To
Docking starboard side to, put the rudder to port and kick the engine ahead until the stern develops a slight swing to starboard. Then go astern to slow or stop the ship: the stern checks up and probably moves to port as the propeller and quickwater take over, but that movement is minimized because the stern was already swinging to starboard before the engine was reversed. The maneuver is repeated until the ship is stopped in position, parallel to the pier.
5.2 Port Side To
Docking port side to, the ship is set up to allow for the same swing of the stern to port. Since the angle of approach decreases each time the engine goes astern, the initial angle is greater for a port-side-to docking. Rudder and engine check the motion to port so the ship does not come parallel until in position; the quickwater partly checks the swing so she lands easily. Knowing the ship swings this way, it is logical to use astern bells to change heading to starboard, slowing the ship and changing her heading at once.
5.3 Do Not Overuse the Rudder
The rudder can often remain hard left through the final stages of a docking, port or starboard side to, because it has so little effect at these slow speeds. Held hard left, it is already in the position most likely to be needed and saves the time the steering engine would take to move it to check a swing. The same applies when backing in an anchorage: the rudder need not be shifted when going astern unless the ship develops significant sternway.
6. Quickwater
Quickwater develops when the astern flow starts moving up the ship's side — first on the starboard side at about 2 knots, and by the time the ship has little headway there is considerable flow up both sides. It strikes first on the quarter, so the stern moves away and the bow heads toward the berth; this effect is more pronounced when docking starboard side to. Eventually the quickwater runs the full length of the ship, affecting her equally fore and aft, and the shiphandler uses this cushion to reduce lateral motion or move the ship off the dock.
Like other forces, quickwater is planned for and used as an aid. It is strongest where there is shoaling or a bulkhead under the berth, which contains the flow and raises the pressure on the hull. If the ship approaches with excessive speed, she must back harder and longer, and the resulting excessive quickwater becomes a problem despite the best planning — one more reason to approach at the minimum possible speed.
7. Bridge Markers
Common sense says a marker or light should be placed on the stringpiece to show where the bridge will be when the ship is in position — yet this is rarely done. Too often the ship is alongside with the first lines run before someone ashore decides she must shift 50 feet ahead or 30 feet astern. The stevedore knows where the working hatch or manifold belongs, and every master knows the bridge-to-bow distance, so the bridge location can easily be marked beforehand. Masters and pilots should work to make bridge markers more common.
8. Use Finesse, Not Force
Going alongside means bringing a moving mass against an unforgiving, immovable pier — an evolution that demands finesse. Beware the master or pilot who boasts of "forcing" a ship into a berth, "belted" full ahead and full astern until "driven" alongside within feet of calamity: that is no professional speaking. In the author's words, shiphandling — like lovemaking — is a subtle art: the ship is not driven, she is caressed, and this must be foremost in mind through the last commands that ease her alongside.
9. Going Alongside
It is extremely important that the ship come in flat to the stringpiece. When the landing is spread over the whole flat parallel midbody, and several hundred feet of nearly incompressible water cushions it, the ship can go alongside with surprising force without damage; landing at any angle loses that cushion. Five reasons make a parallel landing essential.
| # | Why the ship must land flat to the stringpiece |
|---|---|
| 1 | The frames through the entire midbody absorb the impact, instead of it concentrating on a small area of hull. |
| 2 | A parallel landing traps the maximum water between hull and pier, developing the maximum cushioning effect. |
| 3 | The eddy current acts equally along the whole length, slowing lateral motion and easing the landing. |
| 4 | With any current, keeping the ship's upstream end hard alongside stops the current getting inside and forcing her off the berth. |
| 5 | The maximum cushioning from the ship's quickwater is gained when she is parallel to the berth. |
The energy absorbed by this hydraulic cushion is visible: against a solid-faced pier the trapped water often shoots several feet into the air as the ship lands. If the hull lies at an angle, the water rushes toward the end farthest off the pier and the cushion is lost.
10. All Secure
With the ship alongside, the lines are run to make her fast — their number and placement varying with pier, ship, weather, and current. Ships usually run enough head, spring, and stern lines to stop fore-and-aft movement, but these can be a hindrance rather than an aid in a strong current, especially once the ship is allowed to get off the pier at one end.
10.1 Surging and Shock Loading
When the current gets on the inshore side at the bow or quarter, an eddy current develops, the strain on the lines rises, and the ship moves into the current. She rides outward and ahead on the lines — pivoting like a water-skier on a towline — while the lines at the other end pull her back, so she begins surging up and down the pier. The greater strain on the upstream lines causes shock loading that parts lines.
10.2 Breast Lines and Passing Ships
Breast lines — the most effective lines for keeping the ship alongside — are too often overlooked, though they should be doubled up like any other. With enough breast lines, the strain on the forward and after lines stays equal and the ship does not surge. Surging is aggravated by passing ships, whose pressure wave and the low pressure between hulls move the berthed ship away and then toward the passer while pulling her off the wharf. At berths exposed to passing traffic, keep the ship hard alongside with sufficient breast lines and all lines tight.