After you've maneuvered your boat up to its berth (read How to Dock a Boat: Our Top 10 Tips or watch How to Dock a Powerboat, to learn the basics) what comes next? Mooring it, of course. But one little item which could make the process a lot smoother in side-to situations often gets ignored: the spring line.
How it works
How often have you seen one person jumping off a boat, trying – and often failing – to juggle both bow and stern lines simultaneously? Meanwhile, the boat could be temporarily secured to the dock with just a single line taken from the middle part of the vessel, and a little engine power to keep the line taut.
A midship spring takes the hassle out of challenging side-to berthing situations, especially when you’re short-handed, fighting current or wind, or cruising with an inexperienced crew. What is a midship spring? It's a line led from a midships mooring cleat. When (minimal) power is then applied with the wheel turned towards the dock, the effect is to ‘suck’ the boat in sideways against the berth. Leave the engine in gear, and there's plenty of time to rig the regular mooring lines at a leisurely pace—and with no drama. Ideally, the midships spring will lead from the boat to the dock at an angle of around 45 degrees.
The wheel can be tweaked a little to keep the vessel lying comfortably alongside, without banging against the dock. The technique also works if you’re reversing into a space, with the spring taken to a cleat on the dock just ahead of the attachment point on the boat, and reverse power used to keep the line taut.
A midships spring is also useful when tying up to a short finger pier, acting both as a spring to prevent the boat from moving forward and hitting the dock in front, and also helping prevent the stern from swinging away from the finger and into the boat next to you.
There are a number of different approaches to rigging a midships spring line, all of which may be valid on different boats. It’s easiest if you have a midships mooring cleat, since the line can simply be cleated off, with a crew member then stepping onto the dock to secure it.
Tie it amidships, somehow
If you don’t have midships cleats it’s often possible to improvise a lead that will work well – but make sure whatever fitting you secure the line to is capable of dealing with the potentially high loads that may be involved. Typically on a sailboat this will be a genoa sheet car, or spinnaker guy block, with the tail of the line taken back to the cockpit. On a powerboat it could be a stanchion base or mount; choosing a stretchy nylon line for the spring, rather than a low-stretch rope, will help absorb the load. (Watch How to Select and Maintain Dock Lines for more details.) In any case, just make sure that whatever you choose can handle the job.
Leaving a dock
A midships spring can be just as beneficial when leaving a berth. Often it will enable you to remain in place as all the other lines are cast off, leaving just a single rope that can be easily let go. It also allows you to use the wheel to get a head start on swinging the bow away from the dock when the breeze is working against you.
When leaving a finger pier in a marina, it’s possible to move the boat back almost half way out of the berth, using a combination of the bow line plus a midships spring that’s taken to the outer end of the finger. Using the lines in this way means the boat is kept under complete control for the first part of the maneuver.
There are numerous small variations on the theme. A common one for single-handed sailors is to lead the spring through the bridge of the cleat (or via a block near the toe-rail) and then take it back to a primary winch in the cockpit. A bowline is then tied in the end of the line and dropped onto a cleat on the dock. The helm takes up slack on the winch, before gently engaging gear to keep the line tight.
On a boat with high freeboard, a boat hook can be useful to place the bowline over the dock cleat. Another useful tip is to run the line through a short length of hose, which will keep the loop of the bowline open and make it even easier to hook over the cleat.
So, why don’t we see midships springs used more often? To be honest, I’m baffled. I like simplicity and for me it’s the default procedure that I rarely deviate from. And that's a good way to prevent your boat from becoming like the one in this video: Container Ship Destroys a Marina... Don't worry, it almost never happens!