captain nemo's revenge
Engineers are working with acrylic to introduce tourists and vacationers to the wonders of the deep.
By Jack Raplee, Assistant Editor
When audiences watched Walt Disney Studios' adaptation
of the Jules Verne film classic, 20,000 Leagues Under the Sea, they were
introduced to a vast underwater eco-system made possible by 1954-era cinematic
wizardry. Many patrons likely exited the theater discussing the dramatic
and "realistic" scene in which Captain Nemo (played by James
Mason) and the crew of his submarine, the Nautilus, were engaged in an
epic battle with a giant squid.
Despite the oceanographic insights and the Cinema-Scope photography, it
was, after all, only a movie. While escapist entertainment will always
have a place in the hearts of many, today many people are seeking to explore
underwater life and vegetation as it occurs in nature, rather than in
a movie studio.
The
Imax prototype acrylic submarine, which was introduced in 1998, is a smaller
version of the Deep View 66, a 66-passenger acrylic currently under development.
In many tropical vacation destinations, snorkeling and sunbathing are
among the biggest attractions. Revelers are often drawn to the sea to
be near it, in it, or even
under it. Snorkeling and diving both have limitations. The former allows
only mild and shallow water exploration, while the latter can involve
expensive equipment and requires some training.
There is an alternative. Now, tourist submarines offer entire families
an immersive experience in the aquatic ecosystem without even getting
wet.
This is not a new concept, but engineering innovations have been under
way to accommodate the curious patrons by offering a maximum view of sea
life.
Tourist submarines have operated for many years. The first, the Auguste
Piccard, was built for the 1964 Swiss National Exhibition. It carried
40 passengers and granted approximately 32,000 people views of the bottom
of Lake Leman over the course of 16 months.
"Many of these older submarines resembled small-scale military subs
with large, bubble-like portholes for the passengers to look through,"
said Ted Bush, president of Sea Star Submarines in Honolulu, a tour operator
running submarine trips. "Passengers had a good, yet very limited
view of the world outside the submarine."
A Seamless View
In recent years, some tropical resorts, aquariums, and water parks have
constructed underwater walkways, using acrylic material for walls and
allowing patrons a fuller view of the underwater fish and plant life on
the other side. The Shark Encounter at Sea World in Orlando, Fla., includes
an underwater walkway with a 300-degree view inside a shark tank.
At
the Atlantis II resort in the Bahamas, vacationers can ride a water slide
that propels them through an acrylic tunnel in an aquarium shark tank.
"The typical aquarium setting allows visitors to view a fish tank
only through one flat glass window from inside an adjacent room,"
explained David Hayes, the international division manager at Wharton-Smith
Construction Group Inc. of Lake Monroe, Fla. "Shark Encounter features
a view of sharks swimming all around people and the acrylic material makes
the line between air and water appear seamless." Wharton-Smith provided
waterworks utility construction at Sea World, a job for which Hayes was
the project executive.
A similar project involved the Atlantis II resort on Paradise Island in
the Bahamas. Hayes said the resort's Mayan Temple water slide uses a plate
acrylic tube. People are propelled through it by flowing water after beginning
atop the temple outside, and eventually are deposited into a swimming
pool. The plate acrylic tube passes through a large tank inhabited by
mako sharks.
Hayes said that acrylic is stronger and less reflective than glass, making
the view of the water more fluid and providing a safer material for use
under water pressure.
Probing the Depths
"The natural evolution of the porthole tourist submarines is based
on the acrylic designs of these new underwater passages at theme parks
and resorts," said Sea Star's Bush. "The next generation of
tourist submarines is currently being constructed, and we expect to be
using it in about a year." In fact, two such vessels are expected
to begin runs out of Miami next year.
The vessel to which he referred is the DeepView 66 acrylic submarine designed
and built by U.S. Submarines Inc. of Fort Lauderdale, Fla. Through a partnership
with U.S. Submarines, Sea Star has licensed the DeepView 66 submersible
for commercial use once it is completed.
In 1998, a six-passenger prototype submarine was introduced with an acrylic
pressure hull (older porthole-style submarines are steel-hulled). Since
that time, U.S. Submarines has been developing the DeepView 66, which
is capable of carrying 66 passengers and a crew of three, and is nearly
11 times the size of the prototype. DeepView 66 has been designed to the
A1 Manned Submersible classification of the American Bureau of Shipping,
and the pressure hull meets ASME's Code for Pressure Vessels for Human
Occupancy 1.
To meet ASME code requirements, the acrylic is 3 1/2 inches thick and
the submarine itself is rated to withstand a short-term critical pressure
of 10 newtons per square millimeter. That comes to 10 megapascals, or
1,450.37744 psi. Aside from the acrylic construction, the vessel follows
conventional submarine design principles and travels at a maximum speed
of four knots, maintaining autonomous operation for up to 80 hours.
DeepView 66, when completed, will be approximately 107 feet long, weigh
160 tons, and have the ability to dive to depths of roughly 328 feet of
seawater. Passengers will sit in high-backed, cinema-style seats situated
back-to-back along the center of the vessel in an 8-foot-diameter compartment
offering a panoramic view of the sea life around them.
A
mako shark swims around the acrylic water tube at Paradise Island's Atlantis
II resort. Acrylic has lower reflective properties and is stronger than
glass.
According to U.S. Submarines, the DeepView has a main ballast system
of a dozen tanks that provide 24
cubic meters of buoyancy. A variable water ballast tank system will permit
the vessel to maintain neutral buoyancy regardless of passenger load.
U.S. Submarines said that the main thruster is designed to reduce the
effect of efficiency losses of hydrostatic transmission systems. The propeller,
measuring 1.3 meters (about 4.5 feet), has five blades and turns no faster
than 310 rpm. "The motor is a crank-type, five-cylinder radial piston
hydraulic unit fitted with an extension housing for thrust bearings and
a PTFE shaft seal," according to the company's literature.
Cabin pressure is kept close to one atmosphere, and
injections of oxygen maintain the volume fraction near 21 percent in the
cabin. Carbon dioxide is absorbed by a chemical scrubber.
"Tourist submarines provide passengers with a wonderful educational
experience that they otherwise might not have," said L. Bruce Jones
of U.S. Submarines. "Outside of scuba diving, a ride aboard one of
these vessels is the only way many people will ever experience the natural
environment of the inhabitants of a coral reef.
"These vessels can be thought of as aquariums in reverse," Jones
added, "where Homo sapiens are the species on display for the fish."
On the Horizon
Many tour operators offer smaller acrylic submarines and have retrofitted
some of the older models. Sea Star currently operates a 48-passenger Seabus
acrylic in Miami and expects that two DeepView 66 craft will debut in
approximately 12 months. Jones expects there to be some demand for semi-submersible
craft, which may include bars and restaurants, but contends that further
evaluation of the current tour market must be conducted first.
"Acrylic has a great submersive effect, and we expect it will allow
us greater opportunities in the tourist submarine business down the road,"
he said.