Maritime Propulsion

The maritime propulsion indicates the whole of the systems which allow the Navire S and Bateau X to move. It can be carried out using veils, by a Aviron calling upon the man power or by a Propulseur pulled by a Moteur; but one also finds boats not propelled, cash on another means to move (Halage, animal haulage, Dérive…).

Objectives

A system of propulsion must meet several aims:

To ensure a maximum effectiveness, to consume the least possible of fuel while providing an optimal speed.
To allow a sedentary capacity of operation under various conditions: cruising speed, slow speed, bad weather conditions, with full load or on ballast…
To allow, in certain cases, a good maneuverability at low speed by directing the direction of displacement, if the engine is fixed, it is the Gouvernail only which ensures this role and its effectiveness strongly depends on the speed of the boat.
On certain ships, a minimum weight is required (for example for small boats, or on a tug boat). For others, it is a minimum volume (frigates, conveyers of cars…)

Absence of propulsion

A certain number of floating constructions do not have autonomous system of propulsion and need an external intervention to move. The simplest case is that of a Radeau of survival only made up of one float; there is made to remain motionless, or in any case delivered to the currents, while waiting for the helps. The more advanced models have a small sail sometimes. It is also the case for some river barges: they were historically hauled by horses going along the banks of a channel, sometimes by people if the boat is sufficiently light. The system of towing is found in the lock S of the large channels like the Canal of Panamá, where Locomotive S called “mules” tractor draw the ships.

Towing was gradually replaced by the action of a Remorqueur with mechanical propulsion, being able to be used various ways: the Warping, traction by a metal chain, at the beginning of the 20th century; the Towing, where the tug boat draws the trailer with a rope from large diameter, and more running in open sea; the Pushing, where the tug boat pushes the barge by direct action, and reserved with the River navigation.

The advantage of a not propelled barge is to allow a certain flexibility and profitability in the operations: while the barge carries out the operations of loading and unloading to the port (what takes time), the tug boat can be released for another displacement. The system tug boat and barge are still used on the lakes and large rivers, and in open sea to bring the oil platforms to their place of operation. Certain ships are also transformed into end-of-life in their withdrawing their propelling apparatus become obsolete, and by converting them into mobile or fixed barges; it is the case in particular for some Pétrolier S which are used as floating storage units.

Human propulsion

Principle

The muscular force is probably the first driving force of propulsion used on a ship, as the solar Barque of Chéops and its system of oar. In a general way, this type of propulsion consists in actuating a oar made of a handle which transmits the effort towards a shovel which is in water; the oar can either be connected to the boat by a Dame of stroke or a Engoujure, or to be held with two hands. The action carried out consists of a regular to and from, by alternating a phase of thorough shovel in water and a phase of return out of water, or by alternating phases of thorough entirely in water for the scull.

The action of the shovel in water is of two kinds: with the scull, the shovel acts like a Aile, with a moderate Angle of incidence maintaining a flow attached; with the action to row, the shovel pushes water directly towards the back of the boat, in flow completely taken down.

Applications

Several systems exist:

the Godille consists in actuating an oar with the back of the boat, by an oscillating movement in the transverse plan. The scull is very practiced for the propulsion of the appendices, its simplicity (only one oar which swivels in a notch of the table postpones), its output (the shovel works in smoothness, like a profile of wing) and its advantages in operation of accosting (not of obstruction side as for the oars). One can godiller or sat upright, of only one hand. The scull was used in Brittany by frontier runners (or frontier runners, as in Lanildut in Finistere), on rather heavy boats, to transport several people of a bank to the other.
the Pagaie , where an oar is actuated on the side of the boat, without fulcrum, which requires the use of the two hands. It is used on the Canoë S (where each paddler paddle only on one side), on the Kayak S (where the oarsman paddle on the two sides alternatively), and in help on some Dériveur S.
the stroke where the oarsmen, sitting and facing the back of the boat, actuate the Aviron, articulated on a pivot, by traction; one finds it on the boats of the same name. This system was the most used in a historical way, jointly with the veil, in particular for the naval war. The galères sailing in cruising thanks to their aerofoil, used with the combat the combined force of several rows of oarsmen, divided of the two with dimensions ones on several stages, which made it possible to reach speeds and a handiness necessary to the operations of éperonnage, and to free itself from the dependence to the wind when the tactical situation required it.
the vogue where the oarsmen, upright and facing in front of the boat, actuate the oar, also articulated on a pivot, by push. This system is mainly used around the the Mediterranean on boats of relatively small size.
the Pedal boat where a miniature paddle wheel, or a propeller, is actuated by the passengers thanks to pedals, as on a bicycle. This system is reserved for small boats of edge of beach.

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