The trawler yacht stems from its working cousins, the trawler fishing boat and the tugboat. Whether it is tradition or preference, often these yachts are equipped with Bitts and / or Bollards just like their relatives. Of course they have cleats as well, but the Bitts and Bollards are there to do the big jobs.
Whether or not your boat is equipped with one of these babies, you will want to know the correct way to belay a line to one. There are many different styles, so let's look at them first. Even ff your boat doesn't have a Bitt or Bollard you should pay attention anyway. One day a dock that you pull up to will present one of these varying styles, especially if you travel around the world as trawler folks like to do.
Bitts and Bollards are heavily built devices and are used for belaying lines. There are different types of Bitts such as single, double, H-Bitt, Cruciform Bitt and others. Bollards also may have a single post, double posts (either vertical or angled outward from center), Cruciform, staghorn, and many other styles. Sometimes Bollards are called Bitts and vice versa.
Lines rely on friction to keep them attached to Bitts, Bollards, Cleats, Lines, or other things. Friction increases with what is called normal force. Normal force is the perpendicular force between two objects. So, for example, when the load on a line increases (the boat drifts away from the dock and the line tension increases) the normal force between the line and the Bollard increases and the friction increases. If the total friction of the connection to the Bollard is greater than the force on the line to the boat, the connection holds.
Lines can be secured to Bitts and Bollards in such a way that they can be quickly released or made with a more permanent arrangement. The first such method has the problem that a boat tugging on a line can cause it to become undone or alternatively, if a line is positively tied off it can be hard to undo when required. The obvious difficulty with using a pre-tied loop of line is that its size has to be predetermined which may not be possible when the intended object for the bitter end is not in sight. A loop may not be a positively secure way of attaching to a Bollard. It may be used as a Lark's Head however with a double cruciform Bollard which would be a very secure attachment in my opinion and it can be released quickly if it does not have a load on it. If loaded it cannot be easily undone. Another way to more securely attach a loop to a single post Bollard is to place the loop over the Bollard and form another loop behind the Bollard by making a half twist in the loop and then bringing the resulting second loop back over the Bollard toward the front. A larger loop is required for this, but the result is more secure than just dropping a loop over the Bollard.
The bowline has been called the king of knots. Nothing can jam it. It will never slip if properly made. It can be tied in the hand forming a loop that may be dropped over a cleat, Bitt, or piling or formed around a mooring ring.
A ratline hitch or Clove hitch is an easy knot for making a line fast to the standing part of another line, to a spar, to a piling, or to a Bollard. It must be watched as it might undo if slack and is used to temporarily fasten a line. When the Clove hitch is under a strain it will not slip, however, if under a hard strain, it may set up tight and be difficult to undo.
The correct method of securing a line to a double Bitt is to make one turn on the first post of the Bitt and then make several wraps of the line in a figure eight pattern over both posts of the Bitt. This method may be undone quickly if necessary. Further security may be had by belaying the bitter end coming off the Bitt on a nearby cleat. On a single post Bollard the usual way is to use an appropriate sized loop of line over the Bollard or as described earlier or tie several hitches to the Bollard. A Bollard with cross pieces will help keep a loop from slipping off; even so secure ways of belaying are preferred to ensure that the line will not accidentally come off.
A well known method is the Lighterman's Back Mooring Hitch which may be used on a single post Bollard, on a piling, or for heavy towing. Tugboats use this method and it is called the Tugboat hitch and sometimes the Backhanded Mooring Hitch. It is a trusted attachment method and, like the figure eight described earlier, can be undone even with a great pull on it. Once this hitch is learned it's great when you wish to moor to a Bollard (maybe whilst waiting for a lock or taking on water etc.) and can be tied or untied in moments.