Dinghy

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Dinghy of the schooner Adventuress

A dinghy is a small utility boat carried by a larger boat, or the term can refer to a class of small racing yachts. Utility dinghies are usually rowboats or have a small outboard motor while others may use a small sailing rig. They are used for 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 specific use, but now used in its own right for dinghy sailing or rowing.

A small vehicle towed behind a motorhome is colloquially referred to as a dinghy.

1 Types
2 Space Issues
3 Essential hardware
4 Propulsion
5 Other equipment
6 See also
7 External links

[edit] Types

Dinghies range in length from 2 to 6 meters. Larger auxiliary vessels are generally called tenders, pinnaces or lifeboats. The best size of dinghy for most yachts is about 3.5 to 4 meters, 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 used where space is limited. Some newer dinghies have much greater buoyancy and have great carrying capacity relative to length of the boat (see self-rescue dinghies, bottom of this section).

Modern dinghies are typically made of glass-fiber reinforced polyester (GRP) because it requires the least care and does not rot. 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. Wooden dinghies built using the carvel or clinker methods, have a classic look and are easier to handle than the prefabricated craft, despite being heavier. Favored woods, in order of rot resistance, are locust, mahogany, fir and spruce. Bronze is a good material for hardware, as is stainless steel. Working boats usually have galvanized steel, but the hardware must be replaced every few years.

Whaleboats are the classic premium rowboats, with a sharp bow, fine stern lines and a canoe transom. Despite a slight tip and less cargo capacity than prams, they row, motor and sail the best because of their fine lines. Prior to the introduction of fiberglass as a construction material, dories were more popular because their ease of assembly and, thereby, lower cost.

Whitehall Rowboats were the water taxis of the late 1800s until the invention of the small gasoline outboard. Considered one of the most refined rowboats for harbor and lake use, Whitehall Rowboats are a descendant of the Captain's Gig which was used for a similar purpose on a navel vessel.

Dories are sharp-ended boats made of wood, fiberglass or aluminum. They cut the water well, but their initial stability is low, making them feel tipsy in flat water. Consequently, a loaded dory becomes more stable as more of the beam of the boat is submerged. Dories are not generally used as service boats to yachts. A dory can be landed or launched through surf where a Whitehall may flounder.

Prams are similar to dories but are wider with transoms at both bow and stern. They are difficult to tip and carry a lot of cargo but are slow because of their lack of directional stability. Good photos of small prams can be seen at: [1] and [2]. The Norwegian article. A boat-builder's product description.

Some inflatable boats, such as the Zodiac-type inflatable, have a rigid deck and transom which allows an engine to be used for propulsion. They row poorly because of their blunt bows and large wetted surface, but the fact that they are inflated makes them exceptionally buoyant.

Recently, rigid multifunction self-rescue dinghies such as the rotation-molded Portland Pudgy multifunction dinghy[3] and the Clam [4], have been introduced, challenging the idea that sitting in an inflatable liferaft and waiting for rescue is the best solution to the problem of abandoning ship. These boats are meant to serve as everyday tenders and as pro-active self-rescue dinghies. The Portland Pudgy is also becoming popular as a recreational sailing dinghy and motorboat. Because these dinghies are designed for self-rescue they are exceptionally buoyant and have great carrying capacity relative to length.

[edit] Space Issues

Inflatable dinghy

On yachts shorter than 10 meters, 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 meters) 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. Similarly, there are several types of collapsable dinghy available, which are rigid-types that quickly dismantle into a series of flat panels for easy stowage.

An alternative to the traditional inflatable dinghy the addition of inflatable tubes to an existing hard dinghy. In January 2004 Cruising World[5] published a thorough review of several dinghies including options of interest to owners.

[edit] Essential hardware

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 secures the painter (the line that anchors the boat to a dock), and is used for 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 oarlocks. These are the fulcrums that allow effective rowing of the dinghy. Conventionally, a dinghy will have two sweep-oars on each side. The oarlocks should either have ropes and storage pockets or permanent mounts.

A single sculling oarlock on the transom is less traditional, but also adequate. A sculling oar moves back and forth, never leaving the water; This is the traditional oar on a sampan or a sailing yacht. With a sculling oar, a rope should be rigged from the deck to the in-board side of the oar to counter-balance the weight of the oar.

The dinghy is generally inverted amidships on yachts. This keeps the yacht balanced. It also keeps the dinghy secure from waves and keeps 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 the dinghy so that if the towing line breaks, there is a line to grab with a boat hook. This makes retrieval easier at sea, especially if the boat is partially swamped.

To reduce theft, dinghies have names and numbers. On hard dinghies these are usually on the bow. On inflatables, they are on the inside of the transom. Most often, the name is different from 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 target for robbery.

[edit] Propulsion

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 single sculling oar with an oarlock on the rear transom can be a compact emergency oar- it's moved in a figure-eight motion.

Another popular option is an outboard motor. A horsepower per meter of length is faster than oars. Two horsepower per meter can reach hull speed. Ten horsepower per meter will put a flat-bottomed dinghy on plane. Conventionally, the gas tank is placed under the rear thwart. Engines always swing up so the dinghy can be grounded without damage. Since the transom usually needs to be cut down for the engine to fit properly, an engine well should be used to prevent low waves from splashing over the transom and flooding the boat.

The typical sailing rig for a dinghy is a gunter with a two-piece folding mast stepped through a thwart and resting on the keel. It is raised by pulling a rope. A single-sailed gaff rig is preferred over a marconi (with a triangular mainsail and jib) because a gaff rig is simpler and has a lower center of force. 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 become available. They are more compact, help maneuver and are easier to install, but require more attention.

Traditional working dinghies have a lee board that can be hooked over the side. This 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 lee boards have swiveling tips so the dinghy can be landed. Rudders are often arranged so the tiller folds against the rudder to make a compact package.

Racing dinghies usually have a daggerboard or centerboard to better sail upwind. The trunk is in the middle of what would otherwise be cargo area.

[edit] Other equipment

Additional equipment that is generally considered necessary on a dinghy includes the following:

life-jackets for every potential occupant
a hand-bailer
a bailing sponge for light inundation
a large flashlight
a mouth-blown horn (not a loud-hailer, but a breath-blown fog-horn)
signal whistle
signal mirror
flares

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 dinghy 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.