Docking With Spring Lines
By Greg Jones
Most boaters use spring lines when tied up to the dock to limit fore-and-aft movement, but that's not all they're good for. They can also be used to take much of the drama out of docking and to help you get into or out of a tight space with ease. Once you grasp the few principles involved, you'll be able to use the force of the prop to pivot the boat around the spring line. Even in contrary currents or with a wind blowing you onto the dock, it all comes down to balancing opposing forces.
Spring Line Basics
Spring lines run diagonally forward or aft from the boat at a shallow enough angle to limit the boat's fore-and-aft movement. Sounds simple enough, but spring-line terminology can be confusing. A forward spring line is tied to the dock forward of where it is tied to the boat; it stops the boat from moving aft. An aft spring line stops the boat from moving forward, and it's tied to a point on the dock aft of where the line is attached to the boat. Whatever cleat on the boat the spring line is attached to will become the pivot point for your maneuvers. Spring lines can be attached at the bow, at the stern, or in the middle of the boat, at the midship or spring cleats. The force of the prop against the spring line will cause the boat to rotate around that pivot point. Don't expect your first few attempts to go smoothly. Docking well does take practice. But the following tips could help you avoid some of the more common problems people run into when they first try getting on and leaving a dock using spring lines.
Check your cleats. Your boat's cleats need to be properly sized and securely attached. At a minimum you need four cleats, one on each side of the bow and stern. Midship cleats are very useful, especially on boats over 20 feet in length. If your boat lacks them, installing a pair (backed properly) is a simple upgrade.
Your spring lines should be as long as the boat, plus a few feet. They should be made of nylon, which stretches under tension to reduce shock loads, and large enough to grasp easily.
When leaving a dock, double the spring line back to the boat. When you're getting ready to cast off, take the spring line off the dock cleat and run it around the base of the cleat before bringing the bitter end back onboard. Cleat off the end or hand it to the crew member who'll be in charge of that line. When the time comes to release the line, no one needs to be on the dock. A crew member need only release the bitter end and pull the line aboard as quickly as possible.
Make prop walk work for you. Most boats have right-handed props (when looking at the propeller from the stern, it spins clockwise in forward, counterclockwise in reverse), which "walk" the stern of the boat to port in reverse. Prop walk can be used to help get off the dock, particularly when springing the stern out first.
When you apply throttle, do it gently. Wait until the spring line is taut before you apply enough throttle to begin the maneuver.
When you're coming alongside the dock, make sure the crew keeps clear and stays on the boat. To avoid serious damage to stray body parts, make sure that fenders are the only things that ever come between your boat and the dock. Heroic leaps, dockline in hand, may provide comic relief if all goes well, but they can also result in serious injury. All crew members should learn to accurately heave a line to someone on the dock and practice this skill until it becomes second nature.
Springing Off A Dock
Let's go through, step by step, how to get off a dock where you're tied up with a boat directly in front of you. The dock is to port, and a breeze is piping up from the starboard-side bow quarter, pushing you aft and onto the dock. You need to swing the bow out while keeping clear of the boat in front of you.
Begin by briefing your crew on the maneuver. Double back the forward spring line (the one running from the stern diagonally forward), and cleat off the bitter end on the stern cleat. Designate one crew member to handle the forward docklines and to be ready to deploy a fender if you get too close to the boat ahead. Designate another crew member to handle the stern docklines and to be ready to deploy a fender between the stern and the dock. Now you're ready to spring off the dock, which you do in three steps as shown in figure to the right.
1. With rudder amidships, start the engine and put the transmission into reverse. When the boat comes up against the forward spring line, all of the other lines should be slack and can be retrieved. The only line left holding the boat to the dock is the forward spring line.
2. Have the stern crew take the fender and place it between the boat and the dock, holding on to the fender's line. With the engine still in reverse, steer as though to back down into the dock. The boat will want to back to port, and prop walk will exacerbate that, but the spring line will prevent the boat from moving backward and pull the stern into the dock. Apply gentle power astern. The bow will slowly pivot out, away from the dock, and the stern crew's job is to keep the fender deployed properly.
3. When the bow has fully cleared the boat ahead, bring the rudder amidships and shift into forward as the stern crew pulls in the spring line. Steer to starboard if necessary to clear the boat in front of you while the bow crew stands by with the fender until you are past.
If it's the stern of your boat you need to move out first, the technique is the same but now you pivot on the aft spring line. Prop walk can make a big difference. If the boat is lying starboard side to (with the dock on the right), the prop walk on most boats will swing the stern away from the dock, accentuating the pivot around the spring line. But if the boat is lying port side to with the dock on the left, the prop walk will pull the stern into the dock, and the spring line may not be able to overcome the prop walk to swing the stern out. So when you're docking, think ahead and try to put the dock to the right of the boat. The figure to the right shows how to leave the dock stern first.
1. When the boat comes up against the aft spring line, the bow crew releases the bow line and mans the fender, keeping it between the boat and the dock. The stern crew retrieves the other lines, leaving the boat held in place by the engine and the forward spring line.
2. Turn the wheel or tiller as though to turn the bow into the dock. Power gently forward. The aft spring line will hold the bow against the dock. The stern will swing away from the dock.
3. When the stern is clear of any obstacles aft, retrieve the aft spring line, bring the rudder amidships, put the engine in reverse, and continue astern until you are clear.
A spring line can also be used to get into a tight space on a fuel dock. When you're approaching the dock, have the bow crew set up a spring line off the bow cleat on the side nearest the dock. The line should be looped under the bow cleat, not cleated off, so that the bow crew can control it as you pull into the slip. The figure to the right shows how you get into that tight space.
1. Bring the boat almost alongside the boat behind the space where you want to dock with the rudder amidships and at dead slow speed.
2. Turn into the space with the bow at a 45-degree angle to the dock. Have your bow crew pass the spring line to a person on the dock, who should secure it on a cleat near where your stern will end up. As the line is secured to the dock, ease back on the throttle and turn away from the dock. Your boat will come up against the dock.
3. As your crew slowly lets out the spring line, the boat's momentum should carry it forward into the space. The bow crew can snub off the spring line to stop the boat when it is perfectly "parked." To help swing the stern in, apply gentle throttle. Finish tying up at your leisure with the engine and spring line holding the boat in place.
You and your crew need to learn to coordinate the use of the throttle and the tension on the spring line to get the boat to move in the direction you want. Your first few attempts may not be pretty. Airplane pilots spend a lot of time practicing "touch-and-goes" to improve their landings: At the moment the wheels touch the runway, they apply throttle and take off again. You can do the same thing at a quiet dock. As soon as you've successfully come alongside the dock, head back out. Once you understand the principles, you'll find other ways to use spring lines to make docking less stressful.
Greg Jones lives in Massachusetts and is preparing his 1979 Gulfstar 37 for full-time cruising. His plan is to head south in the fall of 2013.
— Published: February/March 2013
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Springing Around The End
Of A Dock
You've entered the aisle where you're berthed and need to make the turn to enter your slip and tie up on starboard. The wind is pushing you down the aisle and will blow you away from the dock once you're alongside. Your slip neighbor's new trawler is tied up in the berth next to yours. Be careful, or the wind will induce some embarrassing paint swapping. The figure below shows how to handle this situation.
1. Have a crew member set up a forward spring line at the midship cleat on your starboard side. The line shouldn't be cleated off but passed under the horns of the cleat so the crew can control it. Heave the other end of the line to someone on the dock. Have that person cleat it to the outermost cleat alongside your slip at the end of the dock.
2. As you approach the dock cleat, your crew should take up the slack in the line without putting any pressure on it. When the cleat on your boat is near the dock cleat, have the crew member gently snub off the spring line as you turn into the slip and gently apply some throttle.
3. As the bow swings around and points into the dock, your crew can control the boat's movement with the spring line, slowly letting it out to allow the boat to move forward into the slip. You will need to apply more throttle to keep the boat moving forward if the bow starts to blow off. Once in the slip, have your crew cleat off the spring line while you continue to power against it. You may need to steer as if to turn the bow away from the dock to keep the wind from blowing the stern off. The boat will remain in position long enough for your crew to put out additional lines.