To simplify cable
and node interconnections, an underwater electro-optical connector will
be used
to connect the cable to the junction box at the node. A
procedure we have
used previously is to start with the cable spool on the ship (RVIB
Nathaniel B.
Palmer, Dynamic Positioning is essential) while anchored in the harbor.
The
cable bitter end would be pulled and floated from the ship using
zodiacs onto the
riprap along the shore and up to the shore base station located in the
IMS
building. The ship would then steam slowly towards the deployment site
in a
large arc while spooling and snaking the cable onto the bottom along a
pre-selected
route. Once on site, the cable is connected to the controller bottle on
PRIMO and
all systems checked out using a high speed wireless Ethernet link to
shore. PRIMO
would then be lowered to the bottom using heavy link chain from a
single point
on the frame while keeping tension on the cable. A dead weight anchor
with an
acoustic release and float would be attached to the end of the chain
and
lowered to the bottom nearby using disposable nylon line .
Retrieval would follow the reverse operation: The
acoustic
release is activated, the float rises to the surface pulling a Spectra
retrieval line which is used to pull the dead weight and retrieval
chain on to
the surface. This chain is then brought
on board and is used to haul in the PRIMO system as the ship thrusts
slowly
astern to come up on the cable. Once on board, the controller bottle
would be
detached from the junction box, the PRIMO frame moved aside, and a
second,
operable PRIMO system attached to the cable. Deployment of the second
system
would follow the plan described above.
Live images from the platform and BPV-mounted
cameras will be used as a final guide to platform placement and to
assure a
stable footing. In addition, an ROV (Benthos Sea Rover, owned by
Gallager/WHOI
or OpenFrame, owned by Asper/USM) will be used to inspect the deployed
PRIMO
system to ensure nothing would interfere with operation of the BPV.
It is anticipated that the mooring will require
annual
removal in the summer months for replacement. By having an identical
platform (including
winch) available for an immediate swap, no onsite maintenance is
necessary
except for cleaning sensors.