Complex sentence: Later that night, Nick decides to move the boat, but Bert tells him it is dangerous at night cause of the rocks, the boat crashes and the gang are shipwrecked on "Dog Island".
Split into simpler sentences: Later that night, Nick decides to move the boat, but Bert tells him it is dangerous at night cause of the rocks. Nick ends up moving the boat, crashing it to wreck and the gang are shipwrecked on "Dog Island".