Rowing a boat requires moving an oar through water, and care must be taken to ensure that the oar does not fall in the water. A thole is a type of system employed in boating to assist in using the oars to row the boat. The thole consists of one or two small dowel-like shafts made of wood or metal which are known as thole pins. These pins are fit into the rowing surface on the edge of the boat, which is referred to as the gunwale.
The choice of a single or dual thole pin system is based on the boat operator's preferences for the boat's use. If a single thole pin is used, it may be employed as a fulcrum for the oar to bear on during rowing. This prevents damage that would otherwise be caused by the interface of the gunwale and the oar and allows for some control over the orientation of the oar. Alternately, an oar can contain a thole insert so the oar may mount onto the pin itself.
If a pair of thole pins is used, the oar is placed between them and limited in its range of motion by the presence of the thole pin on either side. Restricting the motion of the oar in this way provides for greater control of the oar, and consequently, better power distribution for moving the boat through water. Additional fastening methods are possible to further increase power and control. A common design incorporates a stainless steel thole pin attached to a loop, or grommet, made of rope through which the oar is passed.
Thole systems are still in use among boating enthusiasts, many of whom enjoy the traditional look and simple function they provide. Among boaters, oar retention is a wide-ranging topic, and not everyone is in agreement about what the best system is. Some hobbyists, though, particularly enjoy recreating the boating experience as it was centuries ago, and the thole system of locking oars has been around for a very long time, making it an appropriate choice for situations where historical accuracy and preservation are priorities. In these cases, wooden pins provide the maximum authenticity, and the boater can take pride in continuing a longstanding tradition. Others are less concerned with tradition and want modern materials and systems in their boat, and for these individuals, thole systems are likely to take a backseat to more complex methods of oar retention.