Wednesday, May 18, 2011

Docking 101 - Spring Lines

The secret to docking your boat like a professional may be all about spring lines...

Guest blog by Vincent Pica
Chief of Staff, First District, Southern Region (D1SR)
United States Coast Guard Auxiliary

Think "spring" when docking. Photo © Nautical Sites Media

One of the two great mysteries of boating is docking while under the baleful gaze of (pick all that apply: your slip mates, restaurant patrons looking down at you, the dock master). The other is "What Side Of This Buoy Do I Go On?".

This post is about mastering the first.

Two types of spring lines
Spring lines are a little understood and little appreciated aid in proper docking. It is also little understood that there are two forms of spring lines that have opposite functions. One form is the line or lines tied from your boat to the dock that keep it from moving fore or aft while docked. The second form is the line (only one) that is tied from your boat to the dock that allows you to spring into or out of a slip. We’ll discuss both.

The Springing Spring Line
If you’ve ever been confronted with a wind that is blowing you against a dock that you are trying to get away from, you know how difficult (and expensive) that can be. As you power ahead, your stern is being pushed against the dock by the wind. Bump, bump, scratch, scratch, scrape, scrape. Painful, lubberly and potentially expensive. But try this. While at the dock, release all your lines except the bow line. Uncleat it but leave one round turn under the horn so that you have both some purchase plus a way to pull the line free towards you while aboard the boat when you are ready. While keeping that purchase, power ahead slightly. When the boat gets to the end of the still-secure bow line, your stern will spring outwards as the bow is pulled closer to the dock by the momentum of the boat itself. Now, put your engine in reverse, pull the bow spring line back to you as you now easily back away from the dock! This process can be reversed if you can’t power ahead (say there is another boat tied up just ahead of you) by using a spring line off your stern, backing down on it, having your bow spring out and away you go!

What if you have to dock in a tight place and the wind is pushing you off the dock now? The concept is the same. First, cleat a line to the stern cleat closest the dock and throw the bitter end to the dock head. Ask him to cleat it to his dock cleat. Now turn your wheel towards the dock and power ahead slowly. Lo and behold, your boat will move sideways to the dock. This can also be reversed if there is no room ahead. Just tie it to your bow cleat, throw the line to the dock hand for his securing it at his end, and turn the wheel once again towards the dock and then power astern. In both cases, if the wind is too strong at dead-slow on the throttle, you can apply more thrust – as long as those cleat knots are well made. You don’t want to spring free!

The Docking Spring Line
When using a spring line at the dock to secure your boat so that it doesn’t move forward or aft while tied to that dock, the only thing to remember is that the lines are named for the direction that they go in when they leave your boat. An aft spring line goes aft and a forward spring line goes forward. So, if the skipper says “put an aft spring line on the bow and hand it to the dock hand!” he means – go to the bow, put a line on the cleat and hand it to the dock hand who will walk aft and probably cleat it to the dock just past the mid-point of the boat. The skipper will likely then say, “OK, put a forward spring line on the stern cleat and hand that to dock hand.” You will then tie a line to your stern cleat, hand it to the dock hand who will walk it forward and cleat it to the dock, also just past the mid-point of the boat. You now have an “X” formed by the two spring lines criss-crossing each other. The aft spring line keeps the boat from moving forward and the forward spring line keeps the boat from moving aft. In that they are crossed like that, you don’t need to leave any slack in them for the tide changes because they will act like scissors as the boat goes up and down with the tide! BTW, the dock hand could have tied them both to the same mid-cleat on the dock as that does not put double pressure on one cleat. When the wind is on the bow, the forward spring line at the stern is the only one tensioning the cleat. When the wind is astern, it is the aft spring line at the bow that is keeping the boat from moving ahead.

Spring ahead – to better seamanship!

BTW, if you are interested in being part of USCG Forces, email me at or go direct to the D1SR Human Resources department, who are in charge of new members matters, at DSO-HR and we will help you "get in this thing…"

Editor's note: See more seamanship articles by Vincent Pica here on the Daily Boater, or visit his website,



  1. Great Article that every boater should read.
    As a Captain, I see the mistakes all the time. I also see all those folks on the dock watching just waiting for something to happen.
    The photo you have is a great example to use. The boat is sprung from the center cleat to two cleats on the dock. Pretty much it is acting as a pivot point in addition to keeping the boat from moving forward or backward. If at a dock on a floating dock or for a short time, it's not a problem but if on a tidal area, it will be pulled or slacked off the dock. If this boat was tied up at low tide, there would be a good chance that damage to it could occur as the boat is pulled down toward the dock as the tide comes in.
    I've also found that having your spring lines tied to a single center clete is fine on a floating dock, again because you will not have a tidal issue but they will loose the scissor effect and the boat will be pulled or slacked away from the dock. On a fixed dock I would always recommend crossing them. Also I always check to see how far out the spring lines will allow the boat to go and adjust the bow and stern lines equally to that length. Otherwise, you can have a pivoting effect and the bow or stern points can end up against or under the dock. When adjusted correctly, the whole boat will be pulled or slacked against the dock allowing the fenders to protect it.
    When using spring lines to "Spring" and dealing with people on the dock, make sure they understand what you are trying to do. Otherwise, they may just put you in a bind in very short notice. They mean well but, well may not be a good thing when approaching or leaving a dock.

  2. Thanks for the comment and advice Steve - it's always welcome, and as always thanks to Vin Pica for the great content.

    By the way, I took that picture by coincidence at the SailQuest Mystic boat show this past weekend before I knew what Vin would be writing.