Biology Reference
In-Depth Information
The little Delta sub
preparing for a thousand-
foot dive in the Monterey
Canyon. (Photo © 2000
Monterey Bay Aquarium
Foundation. All rights
reserved.)
Arriving on-site, the Point Lobos slowed and scanned the bottom
with its sonar until it was over the right spot. Dave described what
to expect during the dive, including the safety features just in case
anything went wrong down there. To o¤set its buoyancy, he ex-
plained, the air-filled sub has several hundred pounds of lead bal-
last attached to the bottom. If for some reason Dave were unable
to blow the water from the ballast tanks, he could drop this lead
ballast and the sub would rise rapidly to the surface. In case the pro-
peller became entangled in a net or line and the sub became trapped
on the bottom, the entire propeller section could be disconnected
and the water blown from the tanks, and the sub would rise. There
was also, he pointed out, enough oxygen and carbon diox-
ide-removal chemical to sustain life for about seventy-two hours.
We would be down for about two hours and toward the end
of the dive, he said, it would get rather cold. The water temper-
ature at eleven hundred feet is about forty-five degrees, and the
steel hull of the sub has no insulation. He recommended wear-
ing a warm jacket. Then, asking me what I weighed, Dave ad-
Search WWH ::




Custom Search