Steering wheel with rod and with wheel

Steering wheel with rod and with wheel

It must be taken into account that although the objective of both systems is the same, steering the boat, that: In steering with cane:

• The bow falls in the opposite direction to which the rod is put.
• The fall is faster act the tiller directly on the rudder.
• Is easier to stay the course.

In government with wheel:

• The bow falls in the same direction of the wheel turning (just like a car).
• The fall is slower (cables, guards, reduction), although the effort is less.
• Is harder to stay the course since you have to turn the wheel.

Governing and starting speed

• Steering speed: This is the name given to the minimum speed at which the boat is capable of maneuvering properly.
  It will depend on a series of factors, including the blade shape and depth, he number of blades of the propeller as well as its shape, therefore each boat will have a certain one depending on these circumstances.
• Snatch: It is the movement that the boat carries forward or reverse independent of the engine status, it can be with engine stopped, engine forward and back start or engine back and forward start.

Evolutionary curve in forward motion

The evolution curve (or evolutionary curve) is called trajectory described by the center of gravity of a ship when it is turning while holding a speed or engine speed and a constant rudder angle.

To analyze this movement of the ship, we must consider three phases, which are presented one after another from the beginning of the operation, called periods:

• maneuver: includes from the instant in which the rudder begins to be put in until the blade reaches the desired angle (from A to C) Variable: the angle of the rudder remains constant but balance has not been achieved dynamic between all the acting forces (the movement of the ship is variable) the trajectory is curvilinear and will have a decreasing radius (from B to D).
• Uniform: it is produced from the moment in which the balance of external forces is reached and lasts as long as the conditions of machines and rudder in which evolution develops, describing a trajectory of constant radius (starting from point D).

It is important to take into account the stern tail and from the bow since when a ship turns, the Stern moves to a place and the bow toward the other, being the stern, actually the one that is being directed, although the bow turns.
There are, evidently, two points or centers of rotation, a March ahead and another marches back.
These centers are located approximately one third of the bow in forward motion already one third of the stern in reverse.

Therefore, any evolution begins with a considerable displacement of the stern, so care must be taken not to hit the stern.
when we move forward since it is the part of the boat that moves the most (in a 9-meter-long boat, for example, 6 meters move to starboard and only the 3 meters in the bow move to port).
Obviously, in reverse occurs otherwise by moving the center of rotation to one third of the stern.

Expulsion current and lateral pressure without starting

With forward machine, the expulsion current in a propeller right-handed affects the starboard side of the rudder blade so it tends to push the stern to port.
With the machine behind it affects the starboard arch, so the stern is pushed also to port.

As a general rule this current with little start dominates the lateral pressure of the blades, but not with a good start in which the effect of lateral pressure of the blades.

The lateral pressure of the blades: Although the propeller is designed to propel the boat in a longitudinal direction, the rotation of the blades cannot be prevented, When working at higher water pressure at the bottom than at the top, exert a certain transverse force which tends to make the ship rotate on its axis, negligible effect with good forward start but evident when the vessel is stationary or waving.
With propeller right-handed and forward machine will tend to carry the starboard stern and consequently the bow to port and with machine behind will carry the stern to port.

Propeller-rudder effect: Forward start and forward machine

In this case the propeller It sucks in water through its anterior surface and expels it through its posterior surface., towards the stern, so on the rudder blade The propeller expulsion current affects the propeller current, which is added to the current due to start-up.. Therefore the rudder effectiveness increases.

Started forward and machine reversed

The The propeller sucks water towards the bow, so the rudder receives the suction current from the propeller in the opposite direction. to the water flow due to the start so both currents counteract each other and consequently rudder efficiency decreases.

Started back and machine back

In this case The propeller directs the water towards the bow, so the rudder supports the suction current that adds to the water flow due to the launch, so rudder efficiency increases.

Started backwards and machine forwards

The propeller sucks in water from its forward side and throws it aft.
The direction of the start flow is from stern to bow so Both currents counteract each other and the effectiveness of the rudder decreases.

Ciaboga with a single propeller

The ciaboga consists of turn the ship on itself.
Taking into account what was said above about the currents generated by the propeller, if this is left-handed, the turn will be easier to port, and it is right-handed to starboard.
Let's assume that the propeller is right-handed, first we will put the rudder to starboard and then we will give a little forward force.
When the start begins we will give little machine back until starting the rear start and then, forward machine again, and so on so that the expulsion current collides alternately with the starboard face of the rudder and with the starboard vault, in both cases pushing the stern to port and therefore causing the bow to fall to starboard.

Ciaboga with two propellers

On boats with engines with twin propellers with external rotation. to ciabogar just put advance one engine and behind the one of the band where we want to fall.

Agent that influences the maneuver

The agents that will be studied below they are very important At the time of docking or undocking a vessel, however, its live work and especially the dead work also influence.

Wind

To check its direction, it is best to observe the flags of the boats or the beaks of the standing seagulls that are always looking into the wind. Current: It is also important to know its intensity, especially at docking points in estuaries, canals or pipes since in these places its intensity is greater.

Waves

Also of utmost importance, although as a general rule the docking points are usually protected (docks, dock... from the effects of these).

As general rules They will be considered:

dock putting bow to the wind or current (to the strongest element) to be able to govern better. If you dock behind you, you must bear in mind that not governed properly.
If the deadwork is further forward, it will try to bring its bow more into the wind (luffling).

Dejection and drift: Concept

We can consider downwind as the deviation of course to leeward that a ship suffers due to the wind action, while when this deviation It is due to the current or displacement of the mass of water that acts on the living work, is called drift.

Free to leeward

When docking in ports or docks, the spaces are usually limited so you have to avoid obstacles downwind so as not to encounter problems performing the maneuver.