Were there any ships around? Last year I had vacation in Malta and I could barely sleep due to constant, low, barely noticeable noise. I have attributed it to t

Were there any ships around? Last year I had vacation in Malta and I could barely sleep due to constant, low, barely noticeable noise. I have attributed it to the ship engines, as there were many of them around and couldn't find better explanation (tried to turn off every appliance and sleep in different room with no avail).