when n object izz moving in a fluid (not particularly in water bt in any fluid), it xperiences a frictional force dat opposes its motion n hence reduces its velocity.... the intensity of tis opposin' action depends mainly upon the shape of the body...

the efficiency of tis opposin' force depends upon the angle dat the direction of tis force makes with the frontal n peripheral walls of the objects....that's the main reason why a tear shaped or pointed, slender shape izz generally used for submarines n aircrafts....as tis shape reduces the opposin friction 2 a great xtent n hence makes its movement smooth n faster.....

tis wud make u a bit clumsy i think..... but just try 2 understand it in a practical way....

but if u have ne problems regarding tis then ur queries r most welcome.....

have a nice day frward....!!!!!!