Clear sailing, then a glitch
March 26, 2000
By Dr. Dan Fornari
At 0730 hours--18
minutes ahead of schedule--we arrived at the first site where
we will begin surveying the seafloor. Yesterday we had estimated
that we would arrive at 0748 hours. The ships engines
ran at the same speed through the night, so what could have
made the ship move faster than we anticipated? (The
answer is at the bottom of todays Daily Journal).
Now the work
really begins, and everyone has revved up into high gear.
Jim Charters and Uta Peckman of Scripps started testing the
ships multibeam sonar.
from the Woods Hole Oceanographic Institution-Deep Submergence
Operations Group (WHOI-DSOG) prepared the DSL-120 sonar vehicle
for its first lowering to the seafloor. Tom Crook from WHOI and
Melville Captain Buck worked out a minor problem in linking the
DSL-120 computers with the ships Dynamic Positioning (DP)
system, which ensures that the ship maintains its position in a
rolling ocean. Meanwhile, Melville Bosun Bill Kamholtz and his
deck crew were busy fighting the continual war against rust. Maintaining
the ship in a corrosive saltwater environment is one of the crews
At 1542 hours,
Bob Yogi Elder, the WHOI-DSOG expedition leader,
organized the launching of the DSL-120 with Ron Comer, Scripps resident
technician, and PJ Bernard of the WHOI-DSOG team. As the
long, sleek DSL-120 is towed through waters near the seafloor,
it resembles a swimming fish, so we often call it the sonar
fish. Rob Palomares, a Scripps technician,
helped us prepare little MAPRs (Miniature Autonomous Plume
Recorders), which monitor water properties and temperatures.
We are installing four MAPRs on a fiber-optic cable above
the sonar fish and another one below it, so that we get a
close look at the water properties near the bottom. As we
tow the sonar fish above the mid-ocean ridge, these recorders
will help us locate hydrothermal vents.
It takes several
hours to lower the DSL-120 to the seafloor. At about 1900
hours, as the sonar fish approached the bottom, things did
not go according to plan. The DSL-120 was not pinging.
The sonar fish sends out sound signals, or pings,
which bounce off seafloor structures. If the DSL-120 does
not send out signals, no echoes return, and we get a blank
record. Thats what happened.
expeditions, the only sure thing is that there is no sure
thing. Despite all your planning, you have to count on something
going wrong. And then, in the middle of the ocean, you have
to fix the problem--fast. After a lot of testing and thinking,
Yogi and the other WHOI technicians decided that they had
to haul the sonar back up on deck to check out its electronics.
to be a long night of work to fix the sonar. The DSL-120
system is a complex piece of electronic and acoustic equipment,
and many things can go wrong. But the WHOI technicians are
very familiar with all its quirks, and we are optimistic
that they will figure out and fix the problem. The situation
is frustrating for everyone on board, but not unusual. Anyone
who has ever gone to sea is used to these situations.
Answer to Question:
The ship hopped onto a surface ocean current that
was also heading southward. The current helped push the ship
faster toward its destination.