Q.What effect will the wind have on speed over ground and speed through water?

Answer 1 Answers

Both the speed through water and speed over ground will change with the wind.

It will increase of decrease would depend upon the relative direction of the wind.

How much the speed would increase or decrease would depend upon the wind force and ship's windage area.

To understand the concept of speed, we can think of a stationary ship and see what effect the wind will have with respect to a fixed object like an island, (speed over ground) and with respect to a floating object (speed through water).

Let us see this situation where there is no wind, no current and no other external forces. After one hour how much would a ship have moved with respect to a fixed object (speed over ground) and with respect to a floating object (Speed through water)?

I am sure your answer would be Zero.

Now with the strong head wind, the ship would move and so in one hour the distance with respect to the island would have increased. This means that ship would have some speed over ground.

If there are no sea ripples because of wind speed, the position of the floating object would not significantly change.

Hence with respect to this floating object, the ship would have moved some distance in one hour. This means that ship would have some speed through the water.

The conclusion is that speed over ground and speed through water will change with the wind.

Though this is not the case with the current. Why? 

For this and other detailed information on speed over ground and speed through water, you can read this blog.

Speed Through water or speed over ground, Which one to use? 

Harbinder Singh

Harbinder Singh

Oct 10, 2019

Sir, can't the floating object will move because of strong head winds?