Question

even through boat is heavy why don't it sink in the water????​

Answer 1

Explanation:

If the boat weighs less than the maximum volume of water it could ever push aside (displace), it floats. But it sinks into the water until its weight and the upthrust exactly balance. ... In other words, if the boat weighs more than the total volume of water it can push aside (displaces), it sinks.

Answer 2

Because its relative density is less than 1.

$\mathtt{Relative \: Density} = \mathtt{\frac{Density \: of \: Body}{Density \: of \: Water}}$