I bet this has never happened to you! Its blowing a bit as you try and bring your boat into the slip and you are anxious about hitting the boat next to you when the wind takes over as you slow down. But thankfully you see some guys on the dock who are clearly willing to take your lines as you come in. Less anxious now, you head in more confidently, the crew throw the dock lines ashore and you put the engine in to reverse to bring it to a stop. The dock lines are ashore and tied, the engine is stopped and all has gone smoothly... until you notice that the stern line has miraculously untied itself from the cleat and the stern is now being blown across toward your neighbors boat - Something that you manage to stop only by some quick thinking and a handy fender.
Anyone who messes around on boats should be able to tie a dock line securely on to a cleat so that it is secure yet easy to undo. Not an extra slippery slippery hitch or a giant Gordian knot that resembles last nights left over pasta.
And while we're about it; what lines should we use to tie our boat up with anyway?
Securing the lines
Many boat owners choose to use ready-made dock lines with eye-splices already formed in one end. These eyes are then secured either to the vessel or the dock which makes for a neat appearance. Where the eyes are used aboard they can be cast off when leaving the dock and will remain correctly adjusted for your return. But despite this convenience I don't like this system as I prefer to have plain lines which may be cleated both aboard and on the dock. This gives easy adjustment from either end, allows either end to be cast off easily (even when under tension) and creates less risk of a stray eye splice catching on a cleat as you back out under power.
Though many books and instructors teach the use of a cleat hitch with locking turns, I was taught not to use these locking turns and do not do so (Fig 1). This makes cleating considerably easier (just watch the difficulty many crew have figuring out how to add these locking turns correctly) and there is no risk of the hitch jamming. Though these locking turns may add to a feeling of security I have yet to have one of my lines come undone accidently!
What lines do you need?
The lines needed to tie up your boat will depend on the type of dock you are using; whether it is a floating dock with a finger pier on one side or both, whether it is a T-head dock or one with fixed piers. But in all of these situations what you are aiming for is a simple system that will securely hold your boat.
When you are using a floating dock tying up a boat is incredibly straightforward as all lines can be secured tightly as both dock and boat will rise and fall together with the change in level of the water.
Where there is a pier available only on one side, three lines are sufficient to hold the boat securely though a fourth may be added to add a measure of redundancy. Fig 2 shows this situation with bow and stern lines together with a bow spring line which will keep the vessel parallel to the dock; a stern spring may used if desired.
Where there are piers either side, tying the boat with four lines (two at the bow and two at the stern) as shown in Fig 3 makes sense as the vessel may then be held securely without it rubbing against either dock. When tied this way spring lines are really unnecessary and achieve little other than providing a measure of backup.
Where a vessel is tied to a fixed dock, allowance has to be made for the changing level of water. Where there is provision for tying up the vessel at each corner, and the pilings have tide-risers (Fig 4) then it is simply a matter of securing the vessel so that it remains between the piling and so that at high or low water it cannot move over to one side and catch on the dock or pilings. The only real difficulty with this system is that with the vessel tied between pilings it is sometimes hard to get on or off the boat.
The most difficult situation to tie a boat up is where there is only one fixed dock. Where this is alongside a harbor wall or similar, then you will need bow, stern and two springs lines. So long as the water level does not change more than a few feet the lines will be self adjusting so long as the spring lines are both taut and there is a little slack in the bow and stern lines (Fig 5).
Where you are tying to a wooden dock there is the added complication of the vessel slipping under the dock at low water and then getting trapped as the level rises with consequent damage to both dock and vessel. In this situation there is really no choice other than to tie up with bow, stern and spring lines (Fig 5 also) but to remain aboard ready to adjust bow lines and fenders as the water level changes.
Where lines pass through chocks, fairleads or hawse pipes there is a need for protection against chafe if the lines will be there for long or if you intend to leave the vessel unattended. Ideal material to use is canvas (such as firemans' hose) or plastic tubing so long as it can be secured to the line so that it is the part to chafe and not the line iside the protective gear..
When you will be leaving the boat for any length of time or when severe weather (such as hurricanes) threaten, it pays to add extra dock lines. These extra lines should duplicate the existing lines but be left a little slack so that there is no risk of them chafing. They will only be needed if the one of the main dock lines should fail.