That's some very ambiguous handwriting indeed. My first guess was Crebaugh too, but as you said - that doesn't sound very Irish. It's the fourth letter that's causing problems. Have you tried using alternatives like Crefaugh, Crelaugh, Credaugh, or even a surname that ends with -ough? The conspicuous dot on the "e" might indicate it's an "i" in fact.
Hopefully some of our expert members proficient in handwriting deciphering will jump in with some other suggestions!