Understanding Ship Stability and Maritime Forces

Center of Buoyancy

The center of buoyancy is the center of gravity of the volume of water displaced by a float for a given condition. Also known as the center of thrust, as it is, for the purpose of stability, which regards the force applied. It is represented by the letter C and in some publications with the letter B to equate the "Center of Buoyancy" of English.

Since the ship moves in waves, the position of the center of buoyancy is variable and depends on the hull shape and volume submerged at that time. The curve in the transverse plane that describes the center of buoyancy for different angles of rocking is called the curve, and its center of buoyancy ray radii.

Transverse Metacentric

Since by definition the metacenter is in the vertical center of buoyancy of the vessel upright, it is sufficient to know the vertical distance BM to fix its position.

Ship Stability

1. Stable Equilibrium or Positive Stability

When tilting a ship because of an external force, if M is located above G, the arm of the torque generated ago righting the ship.

2. Neutral Equilibrium or Void Stability

In the case of matching G and M, no pair of forces is generated so that the ship shall be shored in position. GM is null.

3. Unstable Equilibrium or Negative Stability

When the center of gravity is higher than the metacenter, the pair of stability will spin the boat in the direction of the arrow and therefore increase its heel.

1. GM + KM > KG

2. KM = KG

3. GM - KM < KG

Marine Current

A marine or ocean current is a translational motion, with continuity and permanence of a given mass of water of the oceans and, to a lesser extent, larger seas. These currents have a multitude of causes, mainly the Earth's rotation (acting differently and oppositely in the deep ocean and on the surface) and the steady or worldwide winds, and the coastal configuration and location of continents.

Coriolis Effect

In more rigorous terms, the Coriolis force is the force that must be exerted on a body not to change its angular velocity when its distance varies with the axis, i.e., the force that must be exercised so that the Coriolis effect is not manifested. This is analogous to the case of the force necessary for a body with a fixed distance from the axis to be maintained; that force is called centripetal force, and its absence causes the appearance of strength (or fictitious force), called centrifugal force.

Tides

A tide is the periodic change in sea level, caused mainly by gravitational forces exerted by the Moon and the Sun.

• High tide: when the seawater reaches its highest point in the cycle of tides.
• Low tide: the opposite time, where the sea reaches its lowest height.

Waves

Waves are waves that travel through the surface of seas, oceans, rivers, lakes, canals, etc.

Ocean Waves

Ocean waves are mechanical waves (i.e., material disruptions to half) of calls surface, which are those that propagate through the interface (the border) between two media materials. In this case, it is the boundary between the atmosphere and the ocean.

Nautical Charts

A nautical chart is a scaled representation of navigable waters and land areas attached. Usually, it indicates water depths and heights of the terrain, the nature of the bottom, details of the coast including the ports, navigational hazards, and the location of lights or other navigational aids. Nautical charts are essential tools for nautical navigation.

Mercator Projection

Gnomonic projection: Represents land surfaces in planes tangent to a point. In turn, there are three classes:

• Polar

Gnomonic projection: Represents land surfaces in planes tangent to a point. In turn, there are three classes:

• Polar