How to Tie a Boat to a Dock: The Four Lines and the Overnight Setup

Coming Alongside: One Line Stops the Boat

Before any of the four lines, there is the line that gets you stopped. Approach at the slowest speed that still gives you steerage, heading into whichever of wind or current is stronger, at a shallow angle to the dock. The first line ashore is not the bow line — it is a midship line, from the cleat nearest the boat's widest point to a dock cleat roughly abeam.

Make that one line fast, put the engine in slow ahead with the helm turned towards the dock, and the boat pins itself alongside and stays there. It is the single-handed docking trick and it works for a full crew too, because it removes the hurry: with the boat held by one line and the engine, everybody else can rig the other four lines properly instead of throwing them. If your boat has no midship cleat, a line from the bow led well aft along the dock does the same job as the aft spring it becomes.

Making Fast: the Cleat Hitch, and Why It Is the Only One

Every dock line ends in a cleat hitch — one full turn around the base of the cleat, a figure-eight over the horns, and a final locking hitch with the line tucked under itself. That is the whole knot. It holds under any load a dock line will see and, unlike almost everything else people tie to cleats, it comes off in the dark with one hand after twelve hours of strain.

Two things ruin it. Piling on extra figure-eights, which does nothing for strength and makes it impossible to cast off in a hurry; and taking the load on the hitch instead of the turn — the full round turn at the base is what carries the strain, the hitch only stops it slipping. The step-by-step, alongside the rolling hitch you will want for chafe, is in our sailing knots guide.

Ashore, dock fittings are cleats, rings or bollards. On a ring or bollard use a round turn and two half hitches, or a bowline if you will be leaving the loop and taking the line back to a cleat aboard — which is the better arrangement anyway, because it lets you adjust every line from the deck without stepping off.

Leading the Lines: Long and Shallow

A line's angle is its personality. A short line at a steep angle is stiff: it holds the boat rigidly and snatches. A long line at a shallow angle is soft: it holds the boat just as firmly in the direction it runs but gives gently across it. So springs run the full length of the boat or further, breast lines are led to cleats ahead of the bow and astern of the stern rather than straight across, and the dock cleat you want is rarely the nearest one.

This is also the entire answer to tide. When a fixed dock is involved and the water rises or falls, a line does not go slack or taut according to its tension — it does so according to its length. A line 3 m long that has to rise a metre stretches by 16 cm. A line 10 m long rising the same metre stretches 5 cm. Short lines hang boats; long lines shrug. On a tidal wall the springs are led as far along the dock as the boat will reach, the bow and stern lines are left slack enough to let the boat drop, and the crew looks at it once at the turn of the tide. On a floating pontoon, which rises with the boat, none of this arises — which is why marinas have them.

Fenders: at the Contact Point, Not Along the Rail

A fender only works where the boat touches, and a boat touches a straight dock at its widest point — the beam — and, once it starts surging, at the shoulder and the quarter. Spread evenly along the rail, half of them are decorative. Hang one at maximum beam, one either side of it a couple of metres apart, and adjust the height so the fender's middle sits on the dock edge, not above it where a wake will pop it up and over.

Tie fenders to the base of a stanchion or a toe rail, not to the top lifeline, which was never meant to carry that load. Against a piling, a fender simply rolls off; use a fender board — a plank hung outside two fenders — or a flat fender designed for it.

As for how many and what size: one fender per three metres of boat, plus one, is the working rule, and about 2.5 cm of diameter per 1.2–1.5 m of boat length — so a 10 m yacht is well served by three or four fenders 20–25 cm across. Dock lines in nylon, for the stretch, at roughly 3 mm of diameter per 2.7 m of boat: 12 mm for a 10–11 m boat, 16 mm at 14 m. Breast lines about two-thirds the boat's length, springs the full length. A line that has gone stiff or fuzzy has already lost the strength you are counting on.

Situation by Situation

The four-line setup is the full version. What you actually rig depends on where you are and how long you are staying.

In a slip

A slip — a finger pontoon on one side, pilings on the other or at the outer end — turns the problem sideways: the boat has to be held off two things at once and touch neither. Bow lines go to the outer pilings, and if the slip is narrow they are crossed, so that the port bow line runs to the starboard piling and vice versa. Crossing them makes each one longer, and a longer line is a gentler one. Stern lines are crossed to the finger's cleats for the same reason. Add a spring each side and the boat sits centred, an arm's length off everything, with room to move a little and no way to reach anything hard.

Rafting up

Alongside another boat, the lines are the same four — to the other boat's cleats — plus long bow and stern lines led ashore past her, so that your weight is on the dock and not on your neighbour's cleats. Masts offset so the spreaders cannot touch when the two boats roll, and the outside boat crosses the inside one by the foredeck, never through the cockpit.

The Overnight Check

Before you leave the boat for the evening, or turn in, walk the dock once with three questions.

1. Push the boat. Forward, then aft, by hand from the dock. If it moves more than a hand's width, a spring is slack or missing. If it swings out, a breast line is.
2. Look at every edge a line crosses. A dock edge, a fairlead, a warp rubbing on a stanchion. Lines fail at the chafe point, never in the middle, and a length of hose or a purpose-made chafe sleeve is cheaper than the line. If a blow is forecast, double the springs.
3. Look at the fenders from the dock, not the deck. From above they all look fine. From the dock you can see the one hanging above the edge and the gap where the quarter will touch when the boat surges.

Then leave the shore lines alone. The urge to tighten everything until the boat cannot move is the urge that hangs boats on tidal walls and pops fenders on pontoons. A well-tied boat moves a little, gently, in every direction — and not at all along the dock.

The Night the Alarm Gets Off

Tied to a dock with four good lines is the one night of a cruise when the anchor alarm stays in the drawer: the boat is held by structure you rigged and can see, and a failure announces itself with noise. The same cannot be said of the two other ways a boat stops for the night. On a mooring buoy you are hanging from ground tackle you did not lay and cannot inspect, and a boat that leaves a buoy leaves it silently — which is why we still set a tight alarm, around 40 m, centred on the buoy. And stern-to on a Mediterranean quay only looks like docking: the stern lines are the theatre, the anchor forty metres ahead is what holds you, and the alarm you want there is a creep alarm with a radius of a few metres. Learn the dock version first. It is the one where the lines do everything, and it teaches you what the lines are for on the nights they cannot.

The Bottom Line

Two lines hold the boat in, two lines hold it still, and the still ones are the ones that matter after dark. Lead them long, make them fast with a cleat hitch you can undo, hang the fenders where the hull actually touches, and push the boat once before you go. If it does not move along the dock, you have done it right — and you can stop thinking about it until morning, which is the whole point of a dock.