specifi cally to help provide
range and bearing to the
team as the ROV approaches
a target. Which, even with all
of the modern technology, is
not easy.
“We’re dealing with an
environment that is very
harsh,” says Robert Kraft,
director of Petrel’s subsea
operations. “It is thousands
of meters deep, and it’s very
unpredictable.”
In order to send the ROV
down to a target that’s miles
under the surface, the crew
needs to work with extreme
patience while manipulating
the joystick in the control
room. The Argus Bathysau-
rus ROV has heavy-duty
fi berglass framing to with-
stand the increased pressure,
as well as horizontal and ver-
tical thrusters and a gyro,
among other gear. To see
beneath the water, the ROV
has nine cameras for viewing
and locating the target. Once

the target is located, it has an

HDTV video system capable

of livestreaming 1080i HD

video to the surface through

the cable umbilical cord. It

is through these images that

the Petrel crew brought the

images of the wreckage of

the Lexington to the surface.

Through the photos and

videos, we could see large and

intact sections of the carrier,

with the name Lexington

stamped into the steel on the

stern, as well as anti-aircraft

guns and a turret-mounted

gun with a 5-inch barrel that

appears in the video as if we

are swimming up to it with a

snorkel. We can see a largely

intact fi ghter plane with the

Air Force insignia — a red

circle inset into a white fi ve-

point star inset into a blue

circle. One of the planes even

showed four Japanese rising-

sun fl ags on its fuselage,

indicating four confi rmed

dogfi ght kills. The imagery

is stunning, and it would not

be possible without teams

like the Petrel crew using

advanced technologies to

deliver it.

After the Lexington, the

Petrel crew went on to locate

and video the USS Juneau and

the USS Helena before head-

ing back to their home port to

reboot for the next mission.

With every undertaking, they

are bringing a bit of history

back from the depths.

THE RECREATIONAL EXPLORER

Don’t have room on your boat for a gigantic AUV or ROV?

You can still get detailed imagery of your local seafl oor

with either chirp or sidescan sonar, with companies such

as Simrad, Lowrance, Garmin and Humminbird off ering

accessible versions of both. One cool multibeam sonar

system to check out is Furuno’s DFF-3D, a phased-array

system that reads to the side, as well as up and down.

Coupled with Furuno’s compact Thru-Hull or Transom

Mount multibeam transducer, it can produce traditional

fi sh-fi nder graphs, imagery to either side of the boat, and

detailed 3D images of the ocean fl oor. It has sidebar detec-

tion up to 650 feet over 120-degree swaths, and its main

beam can penetrate to over 980 feet directly under the

boat. While that’s about one-tenth the depth capabilities

of Petrel’s AUV, it’s enough to provide exceptional 3D im-

agery of your local shipwreck so you know where to drop

a line or a dive fl ag.

We’re dealing with an

environment that is very

harsh. It is thousands of

meters deep, and it’s very

unpredictable.”

“

We’ rWe

environmenvironm

harsh. Itharsh

PHOTOS: COURTESY PAUL ALLEN (2, TOP LEFT), COURTESY FURUNO (BOTTOM RIGHT)

98 | BOATINGMAG.COM | JUNE 2018