What will be the genotype and allele frequencies of the next generation?

This is a fairly long answer... first you need to get the initial allele frequencies. equation is p2 + 2pq + q2 (p2 and q2 from here on in is p squared and q squared)
Since I am left to assume that counter clockwise is recessive then .36 is the initial q2. Taking the square root of that we get .6 as the initial allele frequency for q. 1-q=p so p=1-.6=.4. In other words, the island initally has 80p (clockwise)alleles and 120q (counterclockwise) alleles since humans are diploid and have two copies of each gene.
Now, the 25 sailors have have added 50 copies of the q allele thereby changing the allele frequencies. The new allele frequencies are (120+50)/250 for q and 80/250 for p. when you do the math you get .32 for p and .68 for q. This will be the allele frequencies for the next generation too.
Now plugging those numbers into the equation that I sited earlier you get .1024 for p2, .4352 for 2pq and .4624 for q2. You can give those a dominant/recessive notation such as WW for p2, Ww for 2pq, and ww for q2 to show genotype frequencies.

The evolutionary force at work is migration.
hope this is what you were looking for.