By James J. Gaughan, Chief Engineer and Angelo Tseudos, Principal, American Bureau of Shipping

Fascination with the underwater wonders of the sea has prompted more than 700,000 passengers1 to venture as deep as 250 feet below the water's surface in tourist submersibles.

All of these passengers have returned safely to the surface after the ride of a lifetime.

Classification is one of the key factors contributing to this excellent safety record. Almost every tourist sub in operation as well as those currently under construction has been or will be designed, built, and tested in accordance with the requirements detailed in the American Bureau of Shipping's "Rules for Building and Classing Underwater Systems and Vehicles." Although the majority of touristsub passengers have probably never heard of ABS, sub builders and operators alike know how important it is to have the American Bureau of Shipping approve their initial design, survey the construction process, and perform periodic surveys during the operating life of the sub.

They know that safety counts; they know that ABS has the technical expertise to make critical evaluations.

The Birth of an Industry Jacques Piccard is credited with designing the first tourist submersible, the Auguste Piccard, which went into service in 1964 for the Swiss National Exposition, where during a 15-month period she carried 32,000 tourists to depths of almost 1,000 feet in Lake Geneva.

After this initial project, development languished for almost 20 years before a small fleet of oilfield submersibles was converted for tourist use in the Grand Cayman Islands by Research Submersibles Ltd. Limited to two passengers, these subs make 90-minute dives to 800 feet along the famed Cayman Wall to view the wrecked freighter the Kirk Pride.

The first company formed to design, build, and operate tourist submersibles specifically for the tour industry was Sub Aquatics Development Corporation, Vancouver, British Columbia, Canada. Sub Aquatics has designed and constructed all five of the 28- and 46-passenger subs in the Atlantis Submersible Caribbean fleet. Two more 46-passenger subs are under construction, one for work in the Bahamas, the other for Hawaii. All are classed by ABS.

The industry has grown to now include 12 major submersible operations at various locations around the world2. Gross revenues from passenger submersible operations totaled almost $16.2 million in 1988, up from $7.9 million in 1987. Revenues for 1989 are estimated to jump to $32.5 million based on 490 available seats in 12 submersibles. The number of passenger seats are expected to increase rapidly. Of the 19 new tourist submersible being built to ABS class, eight could be in operation by the second quarter of 1990, for a worldwide total of 850 seats on 20 submersibles.

The only limit on the phenomenal growth of this industry is the availability of optimum tour sites. The quality of potential sites for 48 -passenger tourist subs is determined by a number of factors according to industry analysts Jones, Matsuo & Associates, Ltd.

• A pool of 500,000 tourists annually, without seasonal highs and lows; • Coral reefs within t h r e e nautical miles of s h u t t l e - b o a t boarding site ( s h u t t l e boats carry passengers f r om shore to t h e dive s i t e to speed u p the operation, since t h e cruising speeds of tourist subs are usually around one knot); • Clear water with good visibility; • Weather and climate to allow at least 300 operating days per year; • A harbor deep enough for a submersible that draws 10 feet of water; and • A nearby drydock capable of hauling a 100-ton vessel for yearly surveys and repairs.

The number of sites meeting these criteria around the world is limited to perhaps 50, and initial investment to start up a tourist-sub operations can reach $4 million. To start up more sites, more economically, on an incremental basis, operators could use 8-, 10-, or 12-passenger subs, rather than 28- or 46-passenger vessels.

Cruise ship operators like to assess the growth potential of their markets based on the number of tourists who have never been on a cruise. Using this same gage—the number of potential riders who have never been on a tourist sub—the market for the tourist-sub industry is indeed huge. Even during this period of rapid growth, the touristsub industry continues to recognize the importance of the classification process to provide for the safety of life and property.

Importance of Classification Builders want technical expertise from a classification society, which is why they have their vessel designs verified and build tourist subs according to ABS's "Rules for Building and Classing Underwater Systems and Vehicles." For owners and operators, safety is essential for profitability. So to extend their profitability, they class their subs with ABS to verify structural and mechanical fitness.

ABS involvement begins with a review of the initial design. ABS engineers perform detailed calculations to assess the hull, mechanical and electrical systems, and life-support systems of a tourist sub. All materials must be specified and certified before construction can begin.

Because of the unique operating parameters of tourist submersibles, ABS focuses particular attention on critical safety aspects during its plan review such as: Normal and emergency resurfacing procedures— tourist subs usually have three methods for quickly and safely returning to the surface even after sustaining significant damage; sufficient stability and freeboard (the vertical distance from the surface of the water to the level of the deck) after surfacing for safe evacuation during worse case scenario weather conditions; safety measures— especially life-support systems— to protect passengers from potential hazards during normal operations and emergency resurfacing.

Tourist subs are not self-sufficient, relying heavily on a surface support vessel. For this reason, ABS closely reviews the overall systems of operations, including the maintenance procedures, the environment of operations, the availability of scuba divers, and emergency lift capabilities.

Tourist subs are designed and built to operate in specific water depths. ABS assesses the structural integrity of the design using advanced computer analyses, performs hydrostatic testing at 1.25 times the design depth, and witnesses a test dive to the design depth before classing the unit with an assigned maximum rated depth.

ABS surveyors are in attendance during the construction process to verify the quality of the materials and the construction methods.

Their most critical responsibilities include: fabrication survey; witnessing both nondestructive testing on components and sections and hydrostatic testing of the main pressure hull, piping systems, gas storage systems, and ballast tanks; performing detailed inspections of critical hull sections in the manufacturing process; verifying the installation and testing of mechanical and electrical systems; checking safety equipment; and verifying the implementation of quality assurance procedures during the fabrication of acrylic viewports.

The technical requirements used by ABS to review acrylic viewpoint designs are based on criteria in the ANSI/ASME (American National Standards Institute/American Society of Mechanical Engineers) publication "Pressure Vessels for Human Occupancy." These criteria were originally developed primarily by Dr. Jerry Stachiw working with the U.S. Navy. Dr. Stachiw's work consisted of analytic studies and extensive testing to establish the suitability of using acrylics for flat and curved viewpoints on submersibles.

ABS-classed submersibles employ redundant ballast and trim, life-support, propulsion, and electrical systems to ensure the safety of passengers. ABS Rules require that submersibles carry at least a 72- hour reserve supply of oxygen and an equal carbon-dioxide-removal capability for a full complement of crew and passengers.

Propulsion systems—usually all electric—have sufficient redundancy to ensure safe operation. All ABS-classed tourist submersibles are equipped with active and passive firefighting systems.

Submerged tourist subs have the capability of maintaining constant contact with a support vessel via dual-frequency telephones. On the surface, subs use VHF marine-band radios.

Submersibles built to meet the stringent requirements of ABS Rules are listed in the ABS Record as Al Manned Submersible. National administrations, lending institutions, and insurers normally require an Al classification or an equivalent rating before permitting a tourist submersible to operate.

During their operating life, ABSclassed submersibles undergo annual surveys and special surveys every three years to ensure that all significant systems are properly maintained.

In addition to its own rules, ABS works closely with—and in some cases on the behalf of—the U.S.

Coast Guard and the maritime agencies of Greece, Panama, and the Bahamas among others. These agencies stipulate crew requirements and oversee operating procedures.

New Developments Maintaining its exemplary safety record while improving the total experience for passengers are the twin goals of the tourist-sub industry.

One example of this is the continuing development of acrylic viewing windows—a critical technical design element of tourist subs. These plastic windows must maintain pressure integrity and still provide a crystalclear view to passengers. One builder— Hyco Technologies Corp., North Vancouver, B.C., Canada, is developing an entire submersible hull composed of acrylic cylinders, which would give sightseers a wraparound view. ABS is working with Hyco and all the builders as they seek new technological innovations.

ABS has gained the technical edge in this and other areas, not only through working experience, but also through years of study and participation in technical societies such as ASME and associations with the leading experts in the world.

ABS continues to be a leader in the classification and certification of commercial diving systems, and land-based hyperbaric diver-training centers.

Technical expertise, innovative thinking based on sound engineering principles, and an uncompromising commitment to safety are the reasons why the tourist-sub industry continues to rely on ABS.

As a major classification society, ABS establishes rules for the design, construction, and periodic survey of ships, offshore drilling units, and other marine structures. Classification certifies adherence to these rules, thus representing that a ship or structure is fit for its intended service. The primary purpose of ABS is to promote the safety of life and property as sea through classification and related services. For free literature detailing the wide range of services provided by ABS, Circle 44 on Reader Service Card

Maritime Reporter Magazine, page 50,  Jun 1989


Other stories from June 1989 issue


Maritime Reporter

First published in 1881 Maritime Reporter is the world's largest audited circulation publication serving the global maritime industry.