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Environmental Factors that Influence Ship Handing
- Wind. Normally acts to force the ship bodily downwind. The force it exerts is proportional to the square of the velocity of the wind; the more freeboard and sail area, the greater the effect of the wind.
- Current. The movement of water exerts a force on the hull is similar to the force of wind against the superstructure, however, the force resulting is much larger for a given current velocity due to the density of water. Thus, current has more effect on the ship than wind does. Deep draft vessels are effected more by current the shallow draft vesels.
- Frictional Wake Current. Friction between the skin of the ship and the water. It is greatest at the stern along the waterline. It increases in shallow water or as speed increases.
- Flood Tide. The period when a tidal current is flowing landward.
- Ebb Tide. The period when the tidal current is flowing seaward.
- Slack Water. The period between the Ebb Tide and Flood Tide when the current is changing direction and no horizontal motion can be detected.