Complex sentence: Dobson who had awoken to the screeching, ran to the forecastle, where he saw Pepe with a knife in his hand prepared to strike, attempting to avoid the blow he was stabbed in the left shoulder.
Split into simpler sentences: Dobson who had awoken to the screeching, ran to the forecastle, where he saw a man (Pepe) with a knife in his hand prepared to strike. Attempting to avoid the blow he was stabbed in the left shoulder.