Hoyer Intro (1) Flashcards
At low speeds, what is responsible for most of the underwater resistance met by the vessel?
Frictional Resistance
What is the definition of momentum?
It is the quantity of motion measured by the product of mass and velocity.
(Motion x mass and velocity)
What is Momentum?
Motion x Mass x Velocity
Generally considered as motion of the ship at the time we no longer want it. Especially when action has been taken to stop it.
Frictional resistance depends on?
The wetted area and the state of the hull on a ship. (Fouling)
Where does pressure most likely build when encountering Longitudinal resistance?
Pressure builds up ahead of the ship
How do bulbous bows help longitudinal resistance?
It offerers less resistance at lower speeds.
Do bulbous bows offer less longitudinal resistance at higher speeds?
Yes, however it is roughly the same resistance at higher speeds.
What does longitudinal & lateral resistance depend on?
The ships shape and speed through the water as well as the ship’s propulsion force when at constant speed.
What are the four motions of a ship?
1.Longitudinal motion
2.Rotational motion
3.Lateral motion
4.Relative motion
What part of underwater resistance plays an important role in ship handling?
Resistance force, which acts on the opposite side of the hull as the exerted force and in opposite direction to that force .
What does resistance force do?
It acts on the opposite side of the hull as the exerted force and in the opposite direction to that force.
What are the results of of propulsion force on longitudinal motion?
Longitudinal resistance exerts a backwards force at the bow which opposes forward motion of the ship.
What are the results of bow thruster force on rotational motion?
Underwater resistance is at the ships side mostly forward.
What are the results of wind force on lateral motion?
A beam wind will move the ship sideways through the water creating underwater resistance. In that case lateral resistance acts in an opposite direction to the wind force.
What is the difference between wind force and current force?
A beam current causes the ship to go sideways without meeting underwater resistance.
