2. Is it safe?
    The answer, in a word, is "very". Today, you can take a trip on one of over 50 tourist submarines in the world.     The fleet has carried over 10 million passengers around the globe during almost thirty eight years of its history,     all in superior comfort and safety. The result - the tourist submarine industry has a perfect safety record, without     a single serious injury to any passenger.

3. What are the factors influencing safety?
    Assurance of submersible safety begins with the design process. Literally thousands of labour hours are required     and hundreds of drawings are generated. Detailed calculations are required in any area of the design. All     materials to be used during construction must be certified and specified beforehand. When the design is finally     complete it will be exhaustively analyzed by the engineers of the regulatory agency and classification society,     and those plans that are satisfactory will be approved. Once all plans have been authorized, construction may     commence. Society surveyors are on hand for the construction process. They assure the quality of the materials     and the construction techniques. They monitor and witness all the production process. Inspectors also verify the     installation and testing of mechanical and electrical systems, check safety devices and examine critical     dimensions. The submarines are equipped with several pumps, fire fighting systems and advanced life support     system. The craft is in constant contact with the surface support vessel via the underwater sonar communication     system, or when surfaced, with a VHF radio. In a brief article it is impossible to describe all the safety features in     a contemporary passenger submarine. But the main point is that the industry has a perfect safety record and so,     classified passenger submarines are statistically the safest form of transportation in the world today.

4. How deep can a tourist submarine go?
    The submarine is certified to dive to a maximum depth of 75 meters. The dive site area in the waters     surrounding Phuket is thirty meters.

5. What is the air pressure inside the cabin?
    During a dive, the air inside the pressure hull remains at the standard atmospheric surface pressure, regardless     of the submarine's depth. So unlike a Scuba diver, who must be concerned about pressure forced physiological     effects, a submarine passenger can dive deeper, and stay submerged for as long as possible.

6. How does the air inside the submarine stay fresh during the excursion?
    The submarine has a sophisticated central air conditioning and life support system. Since the typical undersea     excursion lasts for one hour, the air supply is enough for all the 51 people on board. The air is also dehumidified     and cooled if needed by air conditioning system. Thref is also an instrument on board which controls the quality     of the air on board. For safety reasons the submarine is equipped with a carbon dioxide scrubbing system and     oxygen is added to the cabin to maintain an ambient atmosphref. So the carbon dioxide respired during     breathing might be scrubbed if it is necessary out of the air by the special granular chemical contained in the     main scrubbing system.