Boat Docking Secrets - How to Avoid Springline Snap-back

by Captain John Jamieson on 6 Feb 2015 Docking your boat will always be easier with spring lines. But too much tension on a spring could create a hazard for you, your sailing crew or partner. Practice this easy 'springing-under-control' exercise to become master and commander of your small sailboat--wherever you sail or cruise!

Take Care to Avoid 'Snap Back'

Nylon's ability to stretch and recover makes it the ideal 'workhorse' for anchoring, docking and springing. But if you overload a line--in particular one with elasticity-- you will create a slingshot of sorts. A line that snaps can cause a lot of damage to the human anatomy. Indeed, this danger has been named 'snap back' and for good reason.

Many years ago, US Coast Guard coxswains would tow vessels at sea on heavy nylon tow line. On some boats, the coxswain stood outside just forward of the towing bit--with no protection in between the bit and the helm station. This created a lot of risk when towing large, heavy displacement vessels.

Here's why...

Towlines load and slack as vessels rise and fall in a seaway. To relieve some of that strain, coxswains work to put both vessels 'in step'. The coxswain wants to adjust the tow line length and towing vessel speed so that both vessels rise and fall together on the back or face of a wave. This keeps them 'in step' and minimizes stress on the towline and deck fitting.

But use too much speed, or get in a hurry and big problems can occur. That towline may part if it exceeds the safe breaking load. It can snap back like a giant rubber-band. And it's not just the towline that travels at speeds up to 700 feet per second when snapped. Deck fittings ripped from their mountings could still be attached to the towline as it snaps back!

In years past, some coxswains were injured or killed from snap backs. Now, rescue coxswains and crew are protected by a heavy metal screen or similar device inserted between the towing bit and helm station.

The solution is so simple. Keep your speed as slow as possible, called 'steerage' or 'bare steerage'. Use the slowest speed that still provides you with positive control in the present conditions. This will help protect your sailing crew and other vessels from injury or damage.

Maneuver with this Mindset Secret

You may have heard me talk about how to develop an 'egg fenders' mindset for close quarters maneuvers. Let's review this again. Imagine that you have fenders set to port and starboard. But, those fenders are not air filled chambers of rubber or synthetic material. Instead they are eggs, just like those you buy in the store, but a bit larger.

So, here's the image to keep in mind anytime you need to maneuver in close quarters. Eggs line your hull port and starboard. Now, go dock your boat alongside a pier, wharf, seawall, inside a slip. Or undock your boat. Or, maneuver inside a marina, alongside another vessel, or nearby vessels. Use just enough speed so that if you make contact, those eggs will stay intact. Train your sailing crew or partner with this in mind to help them master good control with minimum speed.

Practice Speed Control for Mastery

Practice springing in and out of a pier with the ultimate in speed control. Choose an open pier clear of other boats. Pick a quiet day with light to no wind and slack current. You will not get underway and will remain tied to the pier throughout the exercise. Follow these easy steps.

1. Rig the side next to the pier with fenders. Attach a long springline from a cleat nearest the pier between the beam and bow. Run the spring aft to a dock piling or robust dock cleat and back to your boat (after bow spring). If you have crew aboard, assign them to a roving fender.

2. Turn the wheel away from the pier or hold your tiller toward the pier. When ready, place the shifter in ahead propulsion at the absolute slowest throttle speed possible. Cast off all dock lines except the spring line. The spring line will hold your boat alongside the pier.

3. Turn the wheel just a few degrees toward the pier (or hold the tiller just a few degrees away from the centerline of the boat). Easy does it. This will be all about control at the slowest possible pace. Watch the stern as it starts to move out from the pier.

Slow it to a crawl so that the stern moves out from the pier just two to three feet--then stop the swing. Hold the stern in position for a few seconds. Move the stern out another two to three feet. Again, stop the swing and hold it for a few seconds. Continue this sequence until the stern makes a 45° to the pier. Hold it in this position for a few seconds.

Shift the wheel or tiller in the opposite direction slow and easy. Easy does it. Now you will bring the stern back in to the pier in the same manner. Dead slow. Move it in a few feet toward the pier; stop the swing and hold it a few seconds. Move it a few more feet toward the pier; stop the swing for a few seconds. Continue this sequence until your boat lies flush alongside the pier. Practice this 'in and out' exercise to master speed control with your engine, springline and rudder.

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Use these sailing tips to become the true master and commander of your small sailboat. Keep docking and undocking maneuvers as slow as practicable for safer tight quarter maneuvers--wherever in the world you sail or cruise!


Captain John Jamieson with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website at www.skippertips.com. Sign up for the Free, highly popular weekly 'Captain John's Sailing Tip-of-the-Week'. Discover how you can gain instant access to 1000+ sailing articles, sailing skills videos, sailing tips newsletters and Free sailing topic e-Books!