First, access the Lost World Of Krematoa island. Will need over 75 "B" Coins. Go to the house and enter it. Give all your "B" Coins to the bear and he will give you dynamite in exchange. When you exit, you should automatically blow up all the rocks in your way. After you complete all the levels, you should end up at the save cave. Go to the left and you will be at the bear's house. Give all of your Cogs to him, and you will unlock the nautilus. You will then have to fight the captain. Stay in the middle of the room and you will not get hit by the fireballs or the laser beam. When they stop, grab the barrel and go to the middle of the room again. You will see a vent on the top of the room. Hold Up and throw your barrel into it. If timed correctly, you will hit him on his propeller. He will fly towards you. At that moment, grab a barrel and go left or right and jump on the laser beam shooter. When he comes to you , wait until he turns around. Then, throw your barrel at the propeller on his jet pack. Do this about three times and he will go back into the background. Use the same strategy until he starts making the floor move. Then, throw the barrel into the vent. If you hit him, he will come towards you again. This time do not touch the barrel. Watch the laser shooter and a short laser will emerge from it. If you lay the barrel down (hold Down and release Y), the laser will curl around it and disappear. Grab the barrel and throw it at the propeller. Take your time, and you will defeat him. After winning the battle, you will get a DK Coin.