The Drowned Bell

A shipwreck is being surveyed. A large bronze bell hangs from the deck of the wreck, fully submerged in seawater. A diver strikes the bell once with a hammer, and a hydrophone floating 2 metres away in the water records the sound. The same bell is later hauled to the surface and struck again with the same hammer, and a microphone 2 metres away in the air records it. The two recordings are compared. In which medium does the sound reach the listener sooner, and by roughly what factor? Answer with the name of the faster medium and a whole number — the approximate ratio of the two travel times, rounded to the nearest whole number.