[TheDarkWraith]

A little warning when using the snorkel: The maps will NOT show you the warning circle for visual range or radar range when the snorkel is raised and the periscopes are down and you are submerged. Thus you have no way of knowing whether the enemy has detected you or not visually or with radar. It's best to stay as deep as possible thus limiting the amount of the snorkel exposed above water to limit detection. The further the snorkel raises up above the water the more likely the enemy will detect you. If you raise a periscope just above the water you'll be able to see the visual detection circle (if you have it enabled in the map options) to see how close you are to being detected with the snorkel raised.

Your biggest problem will be airplanes. As you get no hydrophone contact line for them you have absolutely no way of knowing when an aircraft detected you and is beginning an attack run until after the fact (snorkel raised and periscopes down while submerged). Suggestion: rise to periscope depth and scan horizon frequently for airplanes while snorkeling.