LeRoy Olson, known to everyone simply as Le, is a Principal Mechanical Engineer
at the Applied Physics Laboratory, University of Washington. He has been
involved in ocean engineering projects since 1960. Olson is chief engineer of
the project to try to lift a black smoker chimney off the Juan de Fuca Ridge, a
daunting technical feat that he talks about candidly in this interview.
NOVA: What did you think of John Delaney's idea when you first heard it?
Olson: Well, he came to me and said he wanted to recover something 20 feet tall
and 10 feet in diameter, and I said you're kidding, it'll be too heavy,
probably 120,000 pounds or something. So the first thing I had to do was scale
him down in size. I said, research vessels normally work with maybe 20,000
pounds on their A-frame, and winches and lines are in that ballpark. So, if he
could go with that, I'd be able to try it.
NOVA: You're going to be working on something 8,000 feet down in the sea. What
would someone have to do on land to get a sense of that?
Olson: Well, I suppose if that person has flown at night over Mt. Rainier with
an 8,000-foot line and tried to set something on the top, they might have the
feeling of the difficulty. They would have the advantage of having seen it in
the daylight, so they would know what they're setting it on. That's hard in the
ocean. Normally the pictures we get are maybe six feet square and 30 feet away.
You don't see the overall picture like you would in air. It's hard for people
to appreciate that aspect, I think.
It's also hard for them to appreciate the pressure. At 7,000 feet, it's perhaps
3,500 pounds of pressure on every square inch. Think of a small automobile
sitting on a postage stamp. The animals down there are all full of fluid, so
they're pressure-balanced and it's not a problem. But anytime you put a void
down, with electronics in it, say, the ocean's trying to crush it.
Finally, you could put them on a roller coaster and have them do it at the same
time, because ships don't sit still at sea. At sea you get done about
one-fourth of the work you do in the lab, because if you're not on some kind of
medication to slow your system down, your body automatically does it only after
a while. You may not be vomiting over the rail, but it's hard to think, and
it's even hard to force yourself to think at times. This is hard for people to
realize, unless they've been out on a small boat and been sick a few times.
NOVA: So what's your plan for the recovery?
Olson: We'll take the line that will be used to bring the smoker back and lower
it to the seafloor. When we get the basket that holds the line close to where
we want it, we'll release it with an acoustic release and set it on the bottom.
It may drop five or 10 feet, but it's not going to hurt it. This line melts or
at least weakens at 150°F, so we can't get it close to the structure. I
have a different type of line that looks the same but is made out of aramid
fibers. It can stand 450°F without weakening, and actually chars at more
like 800. So that will be on the outside of the basket.
We've also got to get the recovery sling down, or the cage that has the slings
in it. We may free-fall it from the surface. We'll put a weight on it and
attach the cage and then some floats and a transponder. [The transponder will
be used to locate the cage once it comes to rest on the bottom, and the float
will be used to bring the cage back to the surface.] Then, when we know where
it is down there, ROPOS, the remotely operated vehicle, can go over and pick it
up and carry it over to the structure.
ROPOS will grab the cage, put it onto the structure, and tighten it up so that
we're ready for recovery. ROPOS will then have to come back to the surface to
get the chain saw. It'll be mounted on the vehicle, then ROPOS will go back
down to the chimney and begin sawing. You come in and cut one place, then you
come over here and cut it, probably not at the same level. So we'll have some
multiple cuts around, to weaken the plane. Our greatest fear is that we won't
get enough cut, so that when we hook the line onto it, we can't pull it
When ROPOS is finished cutting, it will go over to the line basket and get the
hook that is on the outside of the line to the surface, carry it over and snap
it into the lift bridle. At that point, ROPOS will go back to the ship. Then
we'll acoustically release the line floats that carry this line to the surface.
We've got about 200 pounds of buoyancy on this line to get it up through the
water column. When the line gets to the surface, we'll pick it up with a small
boat and bring it over to the recovery ship. The line will be strung on the
winch, and we'll take a load on it. At that point we'll break the chimney
NOVA: What will happen if the chimney doesn't break free?
Olson: If it doesn't break loose, you'll have a ship at sea anchored to a rock
on the bottom with a very strong line. We would build another acoustic release
that has a cutter on it, and if we really pull on the chimney and can't get it
loose, we would slide this release down to the cage and acoustically activate
it so that the high-pressure seawater will sever the line, and we'll be free of
the bottom. Then we'll start all over again.
NOVA: Assuming you get the chimney to the surface, is it a challenge to get it
on board the ship?
Olson: When you bring something up that's nine tons, say, and have it at the
fantail—well, think of a wrecking ball. You're trying to control it and get
it onto the ship and secure it. The real tense part is going to be from getting
it at the water interface onto the deck, and that's about a nine-foot rise. And
if it gets away from you there, it can do real damage. The main thing is to
keep people away from being stuck between a solid object and this swinging
thing. We've done this kind of operation before, and in 38 years of going to
sea, I've never hurt anybody yet. Safety is our prime concern.
The big thing is that when you put a line like this on the seafloor, it may
abrade on something down there, and you don't know it. And when it comes up to
the air/sea interface, the part that has been down by the structures abrading
is the thing that's going to hold it when it's coming up through the air, and
that's when the load is the heaviest, because in water, it's displacing
seawater, so it's not as heavy.
NOVA: What would be the worst-case scenario?
Olson: Well, as it came out in the air and got heavy, you'd see it fall back to
the seafloor. That'd be sickening.
Actually, my greatest fear is hurting or killing somebody, and it's a very
strong potential if you get this rock swinging on the deck. That's really my
worry, just keep people out of the way of it and yet control the thing so it
doesn't beat up the ship, too.
NOVA: How will you feel when you see one of these towers on deck?
Olson: We're laying awake nights now thinking about all the things that can go
wrong, so at least we'll get a good night's sleep. It's just like winning a
ball game or anything else: you go out there with a goal and if you don't
accomplish the goal, it's not very rewarding. We engineers have a real
responsibility to the museum and to the scientists, and that's a lot of
pressure on us to perform. A scientist can go out and observe something and
come back with all kinds of information, and he's succeeded. An engineer goes
out with a goal to bring something back, and if it he doesn't bring it back, he
hasn't succeeded. I think that gives you some feeling for how we're going to
NOVA: How is it to work with a visionary like John Delaney?
Olson: It's a tremendous thing. I mean, if we had to work with engineers all
the time it'd be awful dull work. We like to control our environment so much
that we don't want to step beyond. You have to have scientists that really
push. That's part of the reason I've worked here for 38 years: I've worked with
scientists who are breaking the sound barriers, essentially, in the ocean.
Without that, we'd probably be doing other things.