Tying up properly: line lengths, spring lines and chafe

Most people tie a bow line and a stern line, and wonder why the boat still shuffles up and down the dock all night. The missing pieces are the spring lines, and once they are in place everything else becomes easier.

What each line actually does

The bow line stops the bow swinging out. The stern line stops the stern swinging out. Neither does much about the boat sliding along the dock, because both pull roughly sideways. Springs run diagonally — bow to a dock cleat aft, stern to a cleat forward — and those are what hold the boat in place lengthways.

A boat with four correctly set lines sits quietly. A boat with two moves, and the movement is what chews through fenders and rope.

Angles and length

A short line at a steep angle has almost no travel. When the tide drops, it comes tight and either lifts the boat or breaks something. Longer lines led to more distant cleats sit at shallower angles, absorb tidal range and load the fittings far less.

As a rough guide, a spring line should be at least as long as the boat. Bow and stern lines can be shorter but should never be bar-tight at any state of tide.

Allowing for the tide

Where a boat lies to a fixed dock, work out the range and set the lines for the extremes rather than for the moment you tie up. Leaving at low water and returning at high water is when boats get hung up, and the damage happens quietly while nobody is aboard.

On a floating dock this largely disappears, which is why floating berths are so much more forgiving of imperfect line handling.

Chafe: where lines actually fail

Rope wears where it moves against something hard. Chocks, rail edges, dock corners and the lip of a cleat are all wear points. A sleeve of split hose or a purpose-made chafe guard, positioned exactly where the rub happens, is the difference between a line that lasts years and one that lasts a season.

Check by hand rather than by eye. A line that feels furred or unusually warm to the touch after a windy night has been working somewhere it should not.

Fenders do a job too

Fenders should sit at the widest point of the hull at the height of the dock, and they should be tied to a rail or a cleat, not to a lifeline that will bend. Two well-placed fenders beat four badly placed ones.

Adjust them for the state of tide when you tie up. A fender hanging in the water at low tide is decoration.

Knots and cleats

A cleat hitch — one full turn round the base, then two or three figure eights, and a final locking turn only if the load is light — is enough for almost everything. Avoid burying a line under so many turns that it cannot be released under load.

On the dock side, leave a loop rather than a knot where you can. It lets someone free the boat quickly in an emergency without a knife.

Leaving the boat unattended

Double up the critical lines if wind is forecast, add chafe protection at every contact point, and check the fenders are on the right side of the boat for the expected wind direction. Then walk the dock and look at the boat from a distance; problems are far easier to see from ten metres away.

If the berth is exposed, adding a second spring on each side costs very little and removes most of the risk.

A simple standard rig

Bow line, stern line, forward spring, aft spring, chafe protection at each lead, fenders at the widest beam. Keep the set aboard in a bag so the same four lines are used every time and their wear is predictable. Sizes, lengths and fittings for all of it are on the shop page, and we will happily talk through a berth that is giving trouble.

Leaving the boat in a blow

When wind is forecast, the changes worth making are all cheap. Double the lines that hold the boat off the dock, add a second spring on each side, and move the fenders to the side the wind will push the boat towards. Take anything off the deck that can lift, including covers that are not properly secured.

Then look at the boat from the far end of the dock. Problems that are invisible standing next to a cleat — a line at the wrong angle, a fender riding high, a neighbour’s boat swinging closer than it did — are obvious from ten metres away, and that is the check most often skipped.

The short version

• Springs control fore-and-aft movement; bow and stern lines do not.
• Longer lines at shallower angles cope better with tide.
• Protect every point where a line crosses an edge.
• Leave a boat rigged so a single line can be released from the dock.

From our shelves

• Botepon Bungee Dock Lines for Boats, Quick Connect No Knots, Shock Absorbing Mooring Lines — $18.99
• Bungee Dock Lines – Boat Ropes for Docking with 316 Stainless Clips, Built in Snubber — $22.99
• Moclear 4 Feet Bungee Dock Lines for Boats, Mooring Rope, Clip & Loop — $17.99

Where to go next

Browse the full range on the shop page, read the frequently asked questions before ordering, or check delivery timing on the Shipping Policy page. If you would rather ask a person, contact us — the phone reaches the counter.