Let \( x \) be the number of boats each dock can hold. Since there are 16 docks, the total capacity of the marina is \( 16x \).
According to the problem, when 101 boats are in, there are 5 boats left over. This means that the total number of boats that can be accommodated by the docks is \( 101 - 5 = 96 \).
We can set up the equation:
\[ 16x = 96 \]
Now, solving for \( x \):
\[ x = \frac{96}{16} = 6 \]
Thus, each dock can hold 6 boats.