A dinghy is a small utility boat attached to a larger boat. Dinghies are usually rowboats or have have a small outboard motor while others may use a small sailing rig. They are necessary for any off-ship excursions from larger boats, outside of docking at suitably-sized ports or marinas.
When not in the above context, a "dinghy" commonly refers to any similar boat originally developed for that use, but now used in its own right for dinghy sailing or rowing.
Typical dinghy on davit setup
Dinghies range in length from 2 to 6 m. Larger auxiliary vessels are generally called pinnaces or lifeboats. The best size of dinghy for most yachts is about 3.5 to 4 m, because this can carry a complete family or a family's provisions for a month. However yacht size usually is the limiting factor. Folding and take-down multi-piece dinghies are also implemented where space is limited.
The favorite modern material for building a dinghy is glass-fiber reinforced polyester (GRP), because it requires the least care and never rots. Water penetrating the outer coat can cause blistering and damage to lamination but can be prevented with a barrier coat of epoxy resin. Other materials include Aluminum, marine plywood and, with the advent of sturdy, UV resistant urethane varnishes, wood. These wooden dinghies, which are built using the carvel or clinker methods, are considered to be more aesthetically pleasing and easier to handle than the prefabricated craft, despite being heavier. Favored woods, in decreasing resistance to rot, are locust, mahogany, fir and spruce. Bronze is the best material for hardware, followed by stainless steel. Working boats usually use galvanized steel, replacing the hardware every few years.
On yachts shorter than 10 m there is not enough room for a reasonably sized dinghy and yet there is a genuine need for one. Because anchorage is much less expensive than a dock or slip space, owners of small yachts compromise by carrying a small rigid dinghy or deflated inflatable, or by towing a larger dinghy. Dinghies are sometimes used as lifeboats, but, unless carefully planned, such a use may be unsafe since the boat must be reserved for people. Any extra equipment can be stored in containers or bags that are tied to the dinghy.
Rigid dinghies for small yachts are very small (2 m) dinghies, usually with a pram (blunt) bow to get more beam (width) in a shorter length. Larger dinghies are towed and should have reserve buoyancy, an automatic bailer, and a cover to prevent them from being lost at sea. Most masters prefer a tow cable long enough to put the dinghy on the back side of the swell to prevent the dinghy from ramming the transom of the yacht.
Inflatables are inconvenient to tow and take extra time to inflate but are very compact and fit easily into place while at sea. Alternately, owners have experimented with a two-piece rigid dinghy that is towed while in harbor and disassembled into two nesting pieces while off-shore. As long as the joining method is sturdy, these have produced good results.
A dinghy should have a strong ring on the bow, bolted through the keel in such a way that it will not damage the yacht's deck when the dinghy is inverted on deck. The ring is used for securing the painter (the line that anchors the boat to a dock), towing, and anchoring. Additionally, the dinghy should also have two other rings (one on each side of the stern transom) which, with the bow ring, are used for lifting and securing the dinghy for stowage.
The only other essential pieces of hardware are the oarlocks (see Propulsion, below) which are used as a fulcrum to allow for effective rowing of the dinghy. The boat can struggle along with a single set of sculling oarlocks (oarlocks that allow a single person to manipulate two oars) on the gunwale but conventionally will have a sweep-oar arrangement in which each passenger in the boat is responsible for one oar. The oarlocks should either have ropes and storage pockets or permanent mounts.
The dinghy is generally inverted amidships on yachts to avoid unbalancing the boat, to keep the dinghy secure from waves, and to keep water out. When the dinghy is inverted amidships, many yacht owners prefer for it to have handholds built into the bottom. These make launching easier and provide more handholds on deck.
Most yachts launch their dinghies by hand or with a simple lifting tackle rigged from the main mast. Another arrangement, davits over the transom, is convenient and elegant, but sailing in a heavy following sea could cause the loss of a dinghy. If a dinghy is towed, an extra line with a loop in the end (known as a lazy painter) can be attached to a thwart, cleat, or mast step so that if the towing line breaks, there is a line to grab with a boat hook. This extra line makes retrieval easier at sea, especially if the boat is partially swamped.
A name and identifying numbers are stenciled somewhere on the craft to prevent theft. Typically it is found on the bow or, for inflatables, the inside of the transom. Most often, the name is different than that of the main yacht. Otherwise, a potential thief will be able to see when the occupants of a particular yacht are ashore, making the yacht a prime target for robbery.
Conventional dinghies are powered by rowing with one set of oarlocks for each thwart (seat). In some models, sliding thwarts allow far more powerful rowing while in others, a removable thwart can permit standing rowing. A set of sculling oars can substitute for several oars on a dinghy normally powered by sweep-oars. Another popular, albeit more expensive, option is an outboard motor with between 1 and 10 horsepower per meter of length depending on the speed desired. Engines always swing up so the dinghy can be grounded without damage and the fuel tank is generally housed underneath the rearmost thwart. Additionally, since the transom usually needs to be cut down for the engine to fit properly, an engine well is used to prevent low waves from splashing over the transom and flooding the boat.
The typical sailing rig for a dinghy is that of a gunter with a two-piece folding mast stepped through a thwart and rested on the keel. It is raised by pulling a rope and a single-sailed gaff rig is preferred over a marconi with a triangular mainsail and jib because a gaff rig has a lower center of force and a simpler rig. The bottom of the main sail is usually untended (no boom) in order to avoid hitting the passengers with a spar. Recently, power kites have also become popular for propulsion due to their compactness and versatility of control.
Racing dinghies usually have a daggerboard or centerboard to better sail upwind with the trunk in the middle of the cargo area. On the other hand, traditional working dinghies have a lee board that can be hooked over the side which does not split the cargo space. A sailing rudder is usually tied to a simple pair of pintles (hinge pins) on the transom with the bottom pintle being longer so that the rudder can be mounted one pintle at a time. The rope keeps the rudder from floating off in a wave. Both rudders and centerboards have swiveling tips so the dinghy can be landed and rudders often are arranged so the tiller folds against the rudder to make a compact package.
Additional equipment that is generally considered necessary on a dinghy includes the following:
This equipment should be in a bag made of water-resistant materials and tied to a thwart or stowed inside a locker.
Anderson-style self-bailers are also useful for engine-driven and sailing dinghies. These slot-shaped seacocks project into the stream below the hull and open when submerged and moving rapidly. The downside of this solution is that if the boat is beached in sand, it can clog the self-bailers until the boat is inverted and the sand removed. Additionally, these devices do not replace a hand-bailer as they are only useful if the vessel is moving at a moderate speed.
A small anchor can be used to allow the crew of the dingy to fish or rest. Traditionally, a dinghy anchor is either a mushroom shape or a small folding grapple hook with floating rope that will avoid being cut by snags on the bottom. The mushroom is used in locations where the bottom is excessively muddy while the grapple works better in currents. Some persons prefer a small danforth or plow, the same as they would use on a larger boat, but these have sharp edges, and need to be pulled-on to set.
A dinghy should not be able to scratch the mother-boat's paint, therefore a fender made from a length of heavy rope tied loosely to the outside of the bulwarks. This also provides a handhold for launching, or for men overboard to climb into the boat. Many modern dinghies have a molded ridge of plastic to replace the rope. A fitted acrylic canvas cover can shed seas or act as a shade or storage cover. Traditionally it toggles to the fender-rope or is suspended from the gunter (small folding mast) but can also be tied to a few points and secured with snaps or velcro.
Customarily there is a large locker under a thwart with a bronze padlock that is left open at sea. As a rule, the locker is arranged so the boat's painter (rope to the front ring) can be locked around a mooring by placing a loop over a dowel or hook in the locker, and locking the locker.
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