Want to take your camera to 40 meters? Want to start exploring underwater photography? Buying an underwater housing for your camera is the start of this journey. Many companies such as Canon and Olympus actually sell underwater housings for their top selling cameras. There are also a number of third party case manufacturers such as Ikelite and Sea and Sea.
One of the major drawbacks of a compact camera is the size of the lens compared to DSLRs. The DSLRs get around this by the large array of lenses that are attachable to the camera from Super wide angle to Macro lenses allow the user to get sharp images. One of the key fundamental requirements of underwater photography is 'get closer' to the subject to remove excess water between the subject and lens. Compact cameras though are designed primarily for land shots, anything from one meter to infinite is the lenses typical sweet spot, not 10cm away.