appeared to be quite simple, but it required a lot of extensive preparation, which
lasted all morning.
During dive Cy84-08 taking place on the ridge axis at 17°26
0 S Vincent Renard
(chief scientist) asked me to dive with Nivaggioli to the site where the deep towed
engine had been lost in order to try to recover it. At 10:20 AM on January 12,
1984, we arrived on the seafloor and stopped at 2,554 m depth to calibrate the
gyrocompass of the submersible for about 5 min prior to going to look for the lost
vehicle. However, we noticed that we had a problem with Cyana, because we were
light weighted so we had a problem to stay in neutral buoyancy, meaning that
Cyana tended to leave the bottom and rise on its own. We had risen 29 m, and this
ascension could be irreversible if we could not find a way to come down again.
Niva (short for Nivaggioli) was now using the engine propeller to take us back
down to the sea floor again, knowing that this would use precious energy from the
battery. The seafloor was shiny with a freshly quenched glassy crust from a recent
eruption.
There was no sign of the SCAMPI. It seemed that a new lava flow had covered
all signs of faults or fissures on the older lava that was previously seen in 1982.
Indeed, we could distinguish two generations of lava flows by their relative degree
of freshness; the older flow had a dull looking appearance either underneath or at
contact with the new shinier flow. We localized the transponder that gave us the
signal of the location for the lost engine and we started to go towards the target
(course 270°). At 10h49 we were on top of a small volcanic mound with a small
collapsed pit at the top. Than suddenly we found ourselves at the edge of a lava
pond at 2,561 m depth. A large lava pool had drained out, leaving a collapsed roof
and chaotic fragments of rocks and broken pillars. We saw the broken and twisted
wire attached to the lost engine, which was half planted in the wall of the lava
pond about 17 m below us. The scenario was impressive; rock fragments were
partially covering the lost vehicle, which stayed in equilibrium between the wall
and a pillar (Fig. 7.32). The seafloor underneath was about 5 m below the engine.
Then at 10:58 we left the site and moved towards the rope that had been
lowered down to the seafloor to serve in recovering the instrument. At 11h01 we
saw the rope lying on the seafloor. With the mechanical arm we picked up the line
and returned to the lava pond. In the meantime Niva said ‘‘We are still too light
weighted and I should stop to get another rock in order to increase the weight of
the submersible’’. We stopped and Niva took another sample and put it into the
basket. When we reached the target and as soon as we were going to clamp the
hook on the engine, suddenly we felt ourselves being pulled upward. Even after
trying to use the vertical engine to reverse our ascent, it was impossible to come
down again. At 11h09 the pilot, Niva, contacted the surface ship telling them that
we had left the bottom and we were heading up. That was the end of the dive,
which terminated with our failure to recover the deep-towed camera sledge. As far
as I know, the deep-towed Scampi is still there at latitude 17°26
0 30
00 S and longitude of 113°12
0 30
00 W at 2,567 m depth.
In 1993, another French diving expedition conducted by Jean Marie Auzende
(Naudur cruise) took place in the same area where the Scampi had been lost
Magmatic and Hydrothermal Cyclicity
245
lasted all morning.
During dive Cy84-08 taking place on the ridge axis at 17°26
0 S Vincent Renard
(chief scientist) asked me to dive with Nivaggioli to the site where the deep towed
engine had been lost in order to try to recover it. At 10:20 AM on January 12,
1984, we arrived on the seafloor and stopped at 2,554 m depth to calibrate the
gyrocompass of the submersible for about 5 min prior to going to look for the lost
vehicle. However, we noticed that we had a problem with Cyana, because we were
light weighted so we had a problem to stay in neutral buoyancy, meaning that
Cyana tended to leave the bottom and rise on its own. We had risen 29 m, and this
ascension could be irreversible if we could not find a way to come down again.
Niva (short for Nivaggioli) was now using the engine propeller to take us back
down to the sea floor again, knowing that this would use precious energy from the
battery. The seafloor was shiny with a freshly quenched glassy crust from a recent
eruption.
There was no sign of the SCAMPI. It seemed that a new lava flow had covered
all signs of faults or fissures on the older lava that was previously seen in 1982.
Indeed, we could distinguish two generations of lava flows by their relative degree
of freshness; the older flow had a dull looking appearance either underneath or at
contact with the new shinier flow. We localized the transponder that gave us the
signal of the location for the lost engine and we started to go towards the target
(course 270°). At 10h49 we were on top of a small volcanic mound with a small
collapsed pit at the top. Than suddenly we found ourselves at the edge of a lava
pond at 2,561 m depth. A large lava pool had drained out, leaving a collapsed roof
and chaotic fragments of rocks and broken pillars. We saw the broken and twisted
wire attached to the lost engine, which was half planted in the wall of the lava
pond about 17 m below us. The scenario was impressive; rock fragments were
partially covering the lost vehicle, which stayed in equilibrium between the wall
and a pillar (Fig. 7.32). The seafloor underneath was about 5 m below the engine.
Then at 10:58 we left the site and moved towards the rope that had been
lowered down to the seafloor to serve in recovering the instrument. At 11h01 we
saw the rope lying on the seafloor. With the mechanical arm we picked up the line
and returned to the lava pond. In the meantime Niva said ‘‘We are still too light
weighted and I should stop to get another rock in order to increase the weight of
the submersible’’. We stopped and Niva took another sample and put it into the
basket. When we reached the target and as soon as we were going to clamp the
hook on the engine, suddenly we felt ourselves being pulled upward. Even after
trying to use the vertical engine to reverse our ascent, it was impossible to come
down again. At 11h09 the pilot, Niva, contacted the surface ship telling them that
we had left the bottom and we were heading up. That was the end of the dive,
which terminated with our failure to recover the deep-towed camera sledge. As far
as I know, the deep-towed Scampi is still there at latitude 17°26
0 30
00 S and longitude of 113°12
0 30
00 W at 2,567 m depth.
In 1993, another French diving expedition conducted by Jean Marie Auzende
(Naudur cruise) took place in the same area where the Scampi had been lost
Magmatic and Hydrothermal Cyclicity
245