ROTATION MOTIONS

PitchRollYaw

DISPLACEMENT MOTIONS

Longitudinal motion: forward - back (1 - 2)Lateral motion: port sway – starboard sway (3 – 4)

Vertical motion: down – up (5 – 6)

12

4

3

5

6

PITCH

YAW

STABILIZER

ROLL

FLEXIONFLEXION

TORSION

TORSION

SEMS and MARITIME TRANSPORT

Ships and aircraft autopilots are electromechanical systems used to stabilize these structures from the horizontal, as well as navigation systems to keep the course or flight path. In the case of passenger ships, from the horizontal stability control is achieved by means of retractable lateral stabilisers and ballast.

Autopilots measure the degrees of inclination and displacement of the structures but do not measure the elasticity of said structures. Instead the SEMS system as well as the elasticity also measures all inclinations and displacements of the structure, as it would be in the case of the 6 motions that occur in a vessel, which are: 3 turning or inclination movements, and 3 displacement movements as to the following figures.

MEASURES OF ELASTICITY

The network of the elastic measures of the SEMS system along with the network of the remaining 6 measures which the same SEMS detects accurately, would make said SEMS a sensor system similar to the nervous system of the human being; allowing us to know and anticipate in advance the optimal elastic envelope of navigation in accordance with the existing sea conditions, avoiding many of the sinkings of small passengers ships that constantly occur around the world.

BALLAST TANK(full)

BALLAST TANK(empty)

M

MOMENT OF A FORCEResulting magnitude of the product of the value of aforce by its distance from a reference point.In this case M would be called Flexor Moment by the bending produced on the body or beam.

Cg Cb

C C

POSITIVE STABILITY

NEGATIVE STABILITY

BALLAST TANK

MH MH

M1

M2

STABILITY OF A SHIP

The following figure is intended to explain in a simple way the heel (as mechanical effect) that occurs when the rudder of the ship varies the course of navigation according with a hypothetical load condition, in where C corresponds to the Center or Longitudinal Axis on which the boat turns producing the heel or heeling moment MH.Cg = Centre of gravity of the mass of water or ballast. Vector Cg = water or ballast loadCb = Centre of bouyancy due the empty ballast tank. Vector Cb = push

Projecting the vector force Gg and Cb to the Center or rotation axis C, we see that vector Cg (yellow) produces a counterclockwise torque or moment M1, which is contrary to the heel or moment MH which tends to stabilize the ship.On the other hand, the projection of the vector Cb (red) produces a moment M2 in the sense of the heel further destabilizing the vessel, even tipping the ship.

Sinking of the Sewol (South Korea):It is assumed that the overturning and subsequent sinking was produced by an excess of load and the absence of water in the ballast tanks. As is the case with an aircraft, on a ship for each load condition (value of load and its distribution in the ship) there is the corresponding Navigation Elastic Envelope, so the SEMS system would have never allowed such a manoeuvre, either limiting or canceling it. On the other hand, in the event that the heel was inevitable, the system from the first minute would have determined with sufficient accuracy the process and time of the side dump (90 °) and subsequent final tipping (180 °), so the captain would not have doubted from the first moment to order the evacuation of the ferry.Grounding of the Concordia (Island of Giglio):

For all of the above, the captain of the Concordia would have had at any time the exact knowledge of the structural strength of the vessel and its variation after the impact with the reef, also knowing the variation of the stability of the boat by flooding, and knowing the exact maneuver to avoid the permanent heeling of the ship by the displacement of the hull water inside the ship due flooding.

The heeling could be avoided by using the bow thrusters together with the engines to control the ship’s course, so that the grounding of the ship would have done with all accuracy, avoiding the victims produced and subsequent loss of the ship and enormous cost of the refloat.

In summary:The current safety systems: alarms and autopilots, are unable to measure elasticity, so from the point of view of their operativeness, they lack of scientific rigor, and that is the reason why they are considered no reliable as well as being inaccurate in its estimates. Therefore, such systems can not intervene in the correction of pilots mistakes and also are unable to detect maintenance faults or wrong design calculations.

Everything that happened after the impact with the reef was the product of precipitation, mainly due the ignorance of the exact severity of the structural damage and further deterioration, as well as by the ignorance of the speed of the flood and remaining time of the buoyancy of the boat. All these circumstances would have been determined with accuracy by the elasticity measurement of the ship.

Consequently and in accordance with the general strict standards of safety at use in air, sea or land transport; no transport structure should be considered operative without the inclusion of the SEMS system.

Miguel Cabral Martín

BOW THRUSTERS

LIQUID HULL DUE FLOOD

VOLUME OF LIQUID HULL BY FLOOD DUE THE HEEL OF THE SHIP