World 4/4-1


 * B, G and H are submarine nodes.
 * 2 or more DD: E -> F. Otherwise random.

Tips

 * As the boss has no enemy submarines, using ASW gear is not necessary.
 * Chance for reaching the boss node:
 * With 2 or more DD: 37.5%
 * With 1 or less DD: 31.25%