BAYLAB is a small, easily transportable undersea
habitat. It differs from other existing systems by placing habitability
for instruments and electronic devices as a higher priority than that of
the human occupants. For this reason it is called a manned undersea instrument
chamber (MUSIC). It was designed for use in the shallow waters of the Chesapeake
Bay, hence the name “ BAYLAB”. While it is a “saturation diving system”,
most anticipated work will be conducted at depths where the internal pressure
is such that decompression will not be required. At deeper depths, isobaric
offgassing will be conducted inside the system, or surface decompression
will be conducted in a decompression chamber aboard a barge. The very low
energy requirements of the life support and lighting systems allow it to
operate as a self-contained undersea habitat (SCUH) for 3-4 days between
resupply, while maintaining a 24 hour reserve.It
can also be supplied with power, gas, and fresh water by a very small umbilical
from shore or an anchored vessel. It has an ambient pressure only, horizontal,
cylindrical hull 3.9 meters (13 feet) long and 1.5 meters (5.5 feet) in
diameter. While floating on the surface, with the diver hatch closed, an
overhead hatch can be opened for exchange of equipment and personnel. While
submerged, with the overhead hatch closed, divers can enter through a hatch
in the end of the chamber rather than the bottom. A baffle in the entrance
area, which the divers step over, prevents flooding of the chamber. This
unique feature allows BAYLAB to be positioned very close to the bottom,
which is of significant benefit in an area with low underwater visibility.
A transparent, humidity tight door separates the entrance area from the
work area. The work area contains two bunks, two chairs, 2.3 sq. meters
(25+ square feet) of benchtop work area, and 1 square meter (10 square
feet) of wall mounted instrument racks. The entrance area contains a toilet,
cable/gas line thruhull tube, shower, and diving equipment storage area.
Electrical power is 6, 9 and 12 VDC. The“
passive-assisted “ (PA) carbon dioxide scrubber and dehumidification system
uses chemical absorbents, and requires two watts of DC power per occupant.
This very low power requirement is possible because chamber gas is moved
across two-sided beds of absorbent at low velocity rather than being forced
through the absorbent beds. On-board carbon dioxide, carbon monoxide, and
oxygen monitors are equipped with flashing light and audio alarms, which
are activated when the respective gas pressures fall outside preset levels.
Variable voltage, fluorescent reading and local area lights use 3-8 watts
each. A bank of absorbed glass matting batteries supplies on-board power.
These can be recharged in place or transferred to the surface for recharging
in watertight containers. On-board gas supplies consist of high-pressure
air, nitrox, and oxygen. Resupply of these gases can be conducted through
a portable high-pressure line from the support vessel. Video, audio, and
data communication with the shore is by buried cable, or a two megabyte
ethernet-lan system, depending on the site location. An ultrasonic hydroacoustic
system provides wireless audio communication with divers, surface craft
and shore-based personel. An on-board computer records life support parameters,
and data from environmental monitoring systems, and transmits this information
to a shore-based station. Video signals from internal and external cameras
and audio signals from hydrophones are also recorded in the BAYLAB and
transmitted to shore. A “catamaran” serves as the ballast tray and supports
BAYLAB during long distance moves over water. In this mode, the unit has
a draft of 0.6 meters (2 feet). Near the site of bottom deployment, the
final ballast is loaded, and the chamber sinks to a draft of 2.4 meters
(8 feet). It is then towed to the installation site, where the flooding
of on-board variable ballast allows sinking to the bottom. During submerged
operations a lighted marker with a radio antenna will float above the system.
A surface vessel is required on site only during resupply operations. Removal
of BAYLAB from the work site is accomplished by “ blowing” the variable
ballast system to float the system to the surface. If the next work site
can be reached in a reasonable fashion with BAYLAB in its “deep draft”
configuration, it will be towed directly to the new site. Otherwise, it
will be towed to a suitable site for offloading the ballast. The hulls
will then be pumped dry, at which point it will be in a shallow draft configuration,
and BAYLAB will then be towed to a new site, tied to a pier, or removed
from the water. In the shallow draft mode, the system can be towed at a
speed of 5.5 kilometers/hour with our support craft. BAYLAB can be removed
from the water at most marinas equipped with an overhead lift. Its dry
weight is less than 3000 kilograms (6500 pounds). It can then be disassembled
with hand tools into the three major components. Each component can then
be loaded onto a dual axle trailer, which can be towed to a new launch
site by a standard “pickup” truck.