When securing a boat to a pontoon or jetty, it's easy to think grabbing one or two lines and tying them with any knot that feels secure will do the job. And perhaps it will, a lot of the time. But there are good reasons that this isn't common practice, and certainly isn't recommended.

The lines on a boat are there for a reason, and knots have evolved over time to ensure vessels are as secure as possible. It doesn't take very long to get to grips with them, despite how daunting it may seem! And you'll be glad you did when you never have to experience a missing or damaged boat.

The stern line

As you probably know already, a boat's stern is at the rear end; the stern line, therefore, is also situated at this part of the vessel. Tying the stern line to a pontoon keeps the boat from moving away in the opposite direction, therefore keeping it firmly where it should be. This line also keeps the stern level, preventing it from drifting sideways or swaying with the movement of water. Instead of being tied to a cleat straight on, you should tie the stern line to one a few feet away, so the line is angled outwards.

The bow line

Similar to the stern line, but at the opposite – bow – end of the boat, the bow line performs a similar job. It makes sure the bow stays steady and straight and prevents backward drifting. The bow line should also be tied at an outward angle to keep the boat still.

The spring lines

The number of spring lines that are present and used varies, but typically there are two or four. Even if there are four, on your boat you'll probably only need two of them for almost any situation. The spring lines help to make doubly certain that the vessel won't move away to the fore or aft, and they should be tied to cleats diagonally angled towards the middle of the boat to keep it tight and steady.

What knot?

Your two best options here are the bowline or the cleat hitch. Both will keep the lines secure without being difficult to untie.

For the bowline, make a loop, and bring the pontoon end of the line back up through this loop. Bring it around the line and back down through the loop, before pulling it tight. This will leave you with a secure circle that can be fixed around a cleat or ring.

A cleat hitch is made by bringing the line all the way around a cleat, then up over the top from the boat side. Tuck it under the opposite end of the cleat, cross it back over the top, then under, up and over, and under the tied line.

For more information on properly using pontoons, click here!