Water is an obvious requirement for tourist submarine operations. Ideally, the water at the dive site has an average visibility in excess of 5 meters and some marine life in the vicinity. In many cases, artificial reefs, derelict ships and planes and other items can be placed on the sea floor to attract marine life and entertain customers. In Monaco, one enterprising company built a stern section of a second century Roman galleon, complete with artificial amphoras and placed it in 40 meters of water at the entrance to the harbor, along with a diving bell and an abandoned tug boat. The key is to entertain and educate the customers for a dive duration of approximately 45 minutes.
Tourists are the next key ingredient.
For instance, in order to make the operation of a 16-passenger submarine a success, a minimum of 60,000 annual tourist arrivals are required given the best industry capture ratios. The conditions surrounding the dive site are also important. In addition, the surface wave conditions should be below sea state three on at least 270 days per year. Above that, and passenger transfer becomes difficult. An alternate dive site is often the solution.