How to Secure a Boat to a DockDocking vessels at a homeport is usually a routine operation, but wind, waves, wake, tides, and currents can turn an ordinary, everyday maneuver into one that can generate stress. Many entertaining sea stories have arisen from situations in which poorly docked boats have gone adrift, suspended in mid-air from mooring lines, sprung dock or deck cleats, or toppled piles. 

Securing a boat to a dock involves several techniques as well as gear, sized to vessel length, fittings, safety, and dock/slip configuration. Personal preference and convenience also come into play. Using the proper equipment and techniques under any weather condition or dock arrangement to safely dock can save wear and tear on a vessel and neighboring boats, and avoid damage to docks! 

The information presented below can help both seasoned and novice boat drivers secure a boat to a dock safely and confidently. For this article, the tips presented are based on the assumption that the boat is in a slip or at a dock and the lines are ready to be secured.  

Knowing the terms associated with docking and the gear used to connect to terra firma is critical. Following are the very basic terms you should know.

Boat Hook — A pole (usually telescoping) with a top-mounted hook, used to move a boat toward or away from a dock; also used to retrieve mooring lines.

Breast Lines — Maintain a boat in a lateral position in a slip; collectively, bow and stern lines are called breast lines. The hitch used to secure the lines to the dock depends on the type of dock tie point, usually a cleat.

Bow Line — Runs from a forward boat cleat/chock to a dock fixture.

Stern Line — Runs from a stern cleat/chock to a dock fixture.

Chafe and Chafing Gear — Chafe is the wear and tear on lines caused by rubbing against another surface, like another line, boat deck or gunwale, dock surface, piling, cleat, or chock. Chafing gear is any material wrapped around the line, like canvas, rubber, or flexible plastic to reduce abrasion. 

Chock — A flattened deck fitting with an opening to hold lines. Usually aligned with a nearby cleat, a chock guides a line from the boat to a dock tie point and keeps the line in roughly a constant position by reducing lateral movement. On sailboats and larger power vessels, chocks are sometimes called fairleads.

Cleat — A fixture attached to both docks and vessels to hold lines, generally of two types — closed, with a solid base, or open, with center legs to allow a line with an eye to pass through and set over the horns. Deck cleats with the most holding power are through-bolted, with the cleat backing plate secured by screws below the gunwale.   

Eye — The teardrop loop in the end of a mooring, dock or other line, used to secure a boat to a fitting, typically a dock or deck cleat or a bollard, piling, or ring. 

Fender — A round or oblong rubber, foam, or plastic device used to prevent damage to boats and docks. Fender type and size depends on vessel length, dock configuration, tide variations, and other conditions. Under extreme pressure, fenders can burst or roll out of the way.

Hitch — A method of securing a line to a cleat or other device using friction; commonly used to hold a vessel to a dock.  

Spring Line — Keeps a vessel mostly parallel to the dock and allows for tidal changes: identified by the direction it runs from the boat to the dock:   

  • a forward-leading spring runs from an aft or stern cleat toward the bow.
  • an aft-leading spring runs from a bow or forward cleat toward the stern.
  • Spring line length is important. Optimum aft spring length is about one-half the vessel’s length; the forward spring should be about equal to overall vessel length.

Turn — A wrap of the mooring line around a cleat either once (a half-turn) or fully encircling a cleat (round turn), the first step in securing a line.

Types of Material for Boat Lines

The variety and combinations of material used to make line for vessels is almost endless, but in most cases, three-strand nylon is the material of choice for dock lines. The stretching and non-shrink properties of nylon provide a great deal of give when the line is under load; nylon also resists damage caused by sunlight. Some basic points about line are mentioned below.   

  • Almost all marine dealers sell three-strand nylon dock lines in varying diameters and lengths; some have ready-made eyes, making it convenient and economical to outfit the boat.
  • Make sure line diameter is appropriate for cleat horn height as well as boat size and weight.
  • The stretch and non-shrink properties of nylon line can also create safety issues, particularly if the line is under strain and parts. A parted line can cause serious personal injury or boat damage.
  • Polypropylene or polyester material are poor choices for mooring lines; these types deteriorate rapidly in the sun, have comparatively less holding power than nylon and can injure hands.    

Securing Lines to Dock Fittings

A weather hitch around a dock cleat is perhaps the most effective way to secure a boat. If set properly, it allows the line to tighten when under strain, will not work loose and allows for easy adjusting when necessary. To set a weather hitch, use these steps:

  1. Make a half-turn around the cleat base, then bring the line over the top of the cleat.
  2. Wrap the line back under the cleat horn opposite the first turn, then return over the top of the cleat.
  3. Wrap the line under the first horn a second time, then back over the cleat top, making a figure-eight pattern over and around the cleat.
  4. Form an underhand loop and slip over the cleat horn, pinning the free end under the last wrap. Pull the free end snug.

Convenience and safety may dictate whether the dock line eye is set on a deck or dock cleat. Generally, setting the end of the line with the eye on a deck cleat and the open end on a dock cleat allows for easy adjustment from the dock for tide or current changes, or to bring the boat closer to the dock for passenger boarding. On the other hand, some boaters use cleat hitches at both dock line ends and avoid spliced eyes, as they reduce the usefulness of the line by 50 percent, as well as strength. If an eye in the line is needed, a bowline knot is used. Passing the eye through cleat legs and over the horns is the preferred method to secure boats in heavy weather situations.

If docking a boat to a piling, two round turns with a half hitch will effectively hold the line on the piling. The line will slide down the piling unless a nail is used underneath the loop to hold it up. The nail also makes a handy place to hang dock line when departing.

Many boaters combine time-tested techniques, personal preference, and creativity to secure vessels at a home port in the same manner and position after every voyage; some suggestions are mentioned below.  

  • Different tape colors, leather strips, or other indicators attached to lines to identify bow, stern, and spring lines.
  • Dock and spring lines of different colors to distinguish line locations, with a matching color of tape at the cleat or fitting where the line is to be set for docking.
  • Strips of paint on a dock to show where mooring lines and dock cleats should line up. Check with the marina operator before using any permanent marking.

General Suggestions for Docking a Boat

  • Many boaters leave dock lines at the dock while underway and set for easy retrieval (with a boat or gaff hook) upon return, but getting underway with no dock lines can be unsafe. A travel set of lines can be used at transient docks, for more holding power during storms, to tow a distressed vessel, or to replace a line that is lost, frayed, or left behind.
  • Regarding travel lines, generally six lines are preferred: four breast (two bow, two stern, and two springs), generally longer than the lines left at the home slip.
  • Avoid short tying the boat to a dock. Dock lines should be long enough to accommodate high/low tide extremes or strong currents, and with enough slack to avoid undue stress on the lines.
  • In tidal waters, study local tide tables to determine tide change extremes and adjust the length of mooring and spring lines accordingly.
  • If using crossed stern lines, set the lines so they do not constantly rub against each other at the crossing point; consider adding lengths of chafing gear to both lines.
  • When loading or unloading a vessel, keep it tied close to the boat entry point.
  • After securing a boat following a voyage, grip any dock line and pull hard to see how the boat would react in a strong wind or large tidal range.
  • Double check each fender and how it is secured to the boat.

Using the proper equipment and techniques to safely dock and secure a vessel can help boaters save wear and tear on the boat itself and even neighboring boats. Proper equipment is also essential to avoiding personal injury and damage to docks.