Anatomy of a Dive

Things start early on a dive day. Every one is up and at it by 5:30. It takes all hands to pre-dive the sub and prepare the ship for an Alvin launch. I was the electrician so I did the electrical pre-dive. The mechanical group and the electronics boys had their own pre-dive routines to go through. The first thing I would do is disconnect the battery chargers that had been running all night.

This is what really drives Alvin’s schedule. After running the batteries down all day it takes 10 to 12 hours to recharge them. I would then top the battery tanks off with oil and they would be all set for the day’s dive.

Pre-dive is simply checking every system on the sub and getting it ready for the day’s dive. This takes 5 men about 2 hours doing a well practiced routine. Sometimes there are glitches and it’s a scramble to get it fixed and launch on time. Besides the sub a pre-dive routine takes place in the top lab where Alvin is tracked and communications takes place. Also the A-frame and small boat are checked out. In all there are 33 pieces of paper work to be filled out for each dive.

Once the pre-dive is complete the pilot for the day will do his power on checks. With a man standing by outside, the pilot will run all systems to ensure everything is as it should be. He will then call for a “line”. Piled in a bin in the hanger is everything that will go inside the sphere for that days dive. There will be cameras, warm clothing, lunch, cans of lithium hydroxide to remove co2 from the atmosphere and a variety of other items.

When you hear some one call “line!” you stop what you’re doing and help out loading all this stuff.

Once the line is finished the shore power is disconnected and the sub is powered by its batteries. The air conditioning hose is pulled out of the sphere and Alvin is backed out of the hanger till it’s positioned under the A-frame. As soon as the sub stops a couple of the techs will install the dive weights for the day. These are one inch thick steel plates about 10 inches square bolted together to make a stack that weighs 250 lbs. 2 stack are loaded on each side attached to solenoids so that the pilot can drop them from inside. Two are dropped on descent and 2 are dropped for ascent. Usually the pilot is still inside finishing the power on checks. This is the tricky part. When the power on checks are complete Alvin is ready to launch. On most of my dive days I would be up and doing the electrical pre-dive stopping only for a 10 minute breakfast. Finishing that, it was right in the sphere for the power on checks. I would climb out of the sub, descend the ladder to the deck to find my 2 observers for the day waiting eagerly and ready to go with no delay. I on the other hand am wearing the oil soaked work cloths I did the pre-dive in. I have been at work now for a solid 2 hours getting the sub ready and have to change clothes and often shower just from doing the pre-dive and use the head. Meanwhile these folks are standing around tapping their feet and looking at their watches. No pressure, take your time.

Ten minutes later and I’m back. If this were down around the equator I would come out wearing just shorts and sneakers. With the water and air temp. both being in the 80’s the inside of the sphere started warming up as soon as the air conditioner was pulled out. By the time all 3 people are inside and the hatch is sealed the temperature inside will get up around 100 in no time. Eventually it will cool down from the cold ocean water at depth but not for an hour or so. The observers will cool down first as they are leaning against the hull. The pilot however sits on this ridiculous little padded box in the middle of the sphere and spends the day squatting in a hunched over position looking out the front view port. There are a few key items in that box such as a can of lithium hydroxide and a spare microphone for the underwater telephone. It could be a half hour before I put on a t-shirt but in an hour and a half I will be wearing coveralls, a fleece and a watch cap. No shoes were allowed in the sphere so we all had those leather bottomed wool socks.

Now that we are inside and the hatch is closed I’m communicating with the surface controller and the small boat by radio and I’ll talk to the swimmers by sound powered phone. These days the swimmers ride the sub out on the A-frame but in my day they had to get to the sub by small boat. This was due to the Navy certification of the A-frame and it takes them a long time to come around to anything new. Once everything was ready the ship would launch the small boat and turn into the wind. The Launch Coordinator, a qualified Alvin pilot, would then signal the A-frame operator to swing the A-frame out and Alvin would be lifted from the deck. As the A-frame goes out Alvin is about 10 ft. off the deck at the apex of its travel. Fully extended, the bottom of the sub is level with the deck. The Atlantis II had about 8 ft. of free-board or the distance from the deck to the waterline. You could only measure that on a flat calm day. If there was a good sea running, say 8 to 10 ft. then the waves would be licking at the bottom of the sub. The job of timing when to lower the sub to the water is on the Launch Coordinator. I have to say that that is some of the highest pucker factor work I’ve ever done. People have asked me, as an Alvin pilot, have I ever found myself in a dangerous situation. Well, sure but nothing ever brought more sheer terror to my heart than a recovery in 20 ft. and I’m calling the shots. There’s a high potential of screwing up and getting some one hurt. It’s one thing to be in harms way yourself but another when you’re making snap decisions that have your friend’s lives hanging in the balance. Where do you look for a model of how to do this? How many subs in the world are there like this? 4, maybe 6? Not too many hard guide lines here. If you want to do this job you have to be able to think on your feet.

So as a pilot, there you are in the sub hanging off the end of the A-frame when the Launch Coordinator gives the command “latch out and lower away” timing it so the sub comes down in the trough of a wave. This makes it easy on the swimmers because the sub will rise on the next wave putting slack in the lift lines making them easy to disconnect. Depending on the sea state this is a difficult time for the swimmers. If the seas are up the winch can’t haul the lift line in fast enough so you have all this 4” line piling up around you and you have to make sure it doesn’t snag on anything. A lot like herding cats but you get it done. After the lift lines are gone the ship will slack to tow line and the swimmers will disconnect it. The sub is now free from the ship.

Floating there at the mercy of the waves the pilot hangs on to the one inch aluminum pipe “bird cage” inside the sphere. The bird cage supplies the infrastructure to attach panels for switches and meters as well as something to mount the electronics to. I have been the pilot on a dive when the ship had some problem delaying the recovery and we sat on the surface in rough seas for 2 hours. Barf bags for everybody and my arms ached for days just from hanging on to those aluminum pipes. The sub rolls and pitches wildly in heavy seas.

Once the swimmers are in the small boat, finished with their tasks of disconnecting the tow bridle and basket safeties, the coxswain will give the all clear by radio. I would then call the Surface Controller with a final status check and request permission to dive. With a go from him it’s open the ballast tank vents and Alvin begins to submerge, slowly at first but eventually picking up speed to a whopping one mile an hour. This is the maximum speed that the sub will go up and down. Over the years many things have been tried to increase it but it’s a lot like pushing a sheet of plywood through the water. It will only go so fast.

Finally you’re on your way to some relief from the heat and the pitching and rolling. After descending to only 100 meters all sense of motion ceases. No more wave action, just a long free-fall through the water column. One strange phenomenon is that the sub will slowly rotate clockwise as it sinks and counterclockwise as it ascends. As the temperature comes down you start adding layers of clothing. By the time you get to 2000 meters you’re fully dressed.

On the way down there’s plenty to do. The observers will make ready their hand held cameras and voice recorders and the pilot will be monitoring the atmosphere and all off Alvin’s systems preparing for a bottom approach. A lot of strategy about the days dive is discussed and maps are poured over.

Then there is the light show of bio-luminescence. As Alvin descends through the water it disturbs the simple animals that live there and they glow briefly. Except for the red panel lights it’s dark in the sphere and the outside lights are off. Many first time observers are nervous about going below but staring out the window at this sight seen nowhere else takes their mind off the fact that they are in a place where humans don’t belong.

As Alvin approaches the bottom the pilot is watching the altimeter which usually, depending on what the sea floor is made of starts working about 200 meters up. If it’s a rock bottom the altimeter gets a great signal return but if the bottom is all mud a lot of the acoustic signal gets absorbed and you may not get a reading till 50 meters. You really have to be on top of your game here. The text book style of bottom approach taught to every pilot in training is very inefficient. On the way down the pilot will have pumped water in or let water out of the variable ballast system to make a course adjustment in buoyancy based on the weight of the passengers and payload of the day. When you get to 100 meters altitude you drop one 250 lb. weight. Still descending you drop another at 50 meters and come to a stop where you adjust the variable ballast system for neutral buoyancy then drive down till the bottom is in sight. This is the safe and secure way to do it but it also wastes a lot of time. Just like driving a sports car you gain confidence and knowledge in the machine that makes you question arcane rules and you wind up doing it the way that seems best. When I got to this point I was dropping my first weight at 30 meters and the second at 20. I would then drive up hard and come to a stop 5 meters above the bottom every time ready to go to work. Now the fun begins.

When you reach the bottom its worth spending a few minutes there to make sure the sub is neutrally buoyant. Alvin’s variable ballast system consists of six 36 inch Titanium spheres and a pump to take on or remove water allowing the pilot to very accurately adjust the subs buoyancy. Running the pump at depth is very expensive on the power budget though and should be used sparingly. To adjust the subs trim there is 250 lbs. of mercury that can be pumped fore and aft to adjust the nose down attitude. This is a careful balance as to much nose down and you will be diving every time you drive forward. It’s very important to be neutrally buoyant. If you have to run the lift props all the time to stay down they will eat up a lot of battery and it will be a short dive. The same is true if you’re heavy and have to drive up but you will also be stirring up a dust cloud that will ruin the visibility all day. Battery power is everything. Most dives are ended due to low battery power.

Once neutral you’re ready to go. Before reaching the bottom the pilot will have turned on all the necessary systems to start doing the day’s science plan right away. Here the pilot is taking direction from the number one observer having outlined the plan on the way down.

The bottom can take many shapes and composition depending on where you are. Out in the abyssal plains the sediment is miles deep with a texture of clay except for the top 3 inches that’s fluffy. On top of the mid ocean ridges it will be hard rock and basalt with little sediment. This is where you find the hydro-thermal vents. There’s as much variety down there as there is on the surface. As far as biology goes it’s like a desert with the vent areas being like an oasis. Life on the bottom is far and few between. On the plains you might find one starfish in 2 acres. 90% of the life in the ocean is in the top 100 ft. due to the suns rays and photosynthesis. At the hydro-thermal vents, most of which are around 2500 meters deep life abounds. These animals make there oxygen by chemo-synthesis, turning sulfur dioxide into oxygen, A process that is not completely understood and a subject of much study in the oceanographic world. Depending on the size of the vent or vent field you can find a small mix of animals to a huge complex colony. If the vent closes off, something that does happen and often the colony withers and dies.

These vent areas are mostly isolated communities particularly on the mid Atlantic ridge. One vent out there is called TAG. It’s a mound on the ridge that’s venting at 375 Centigrade. That’s about 650 degrees Fahrenheit. Hot enough to melt lead. The top of the mound is teeming with life. Shrimp, crabs, mussels and starfish among others but no big tube worms like the pacific vents. The entire vent mound is no more that 100 feet across and there isn’t another vent for many hundreds of miles. If you get 100 feet away from the vent site there is little or no life at all. This is how isolated the communities are.

Off the coast of Washington state about 100 miles or so is the Endeavor Vent Field. An area about the size of a football field it’s the home to large number of vents and is probably the most studied vent field on the planet due to it’s close proximity to shore and the easy logistics of getting there. Filled with a large mixture of venting structures, most are given names based on scientists first impressions, such as Bastille, Peanut, Twin Peaks and a huge one called Godzilla. There are a few that are named for scientists children such as Rebecca’s Roost but I find that sappy and not very scientific or professional.

The hydro-thermal vents are with out a doubt the most dangerous place to dive in Alvin. In order the sample the fluid that’s chugging out of the vent like smoke billowing from a hole under high pressure, you have to get within arms length of it. On a nicely active vent the water is coming out at temperatures up to 700 degrees Fahrenheit. Bringing Alvin in close enough to sample puts the plastic view ports within arms length as well. Getting in too close could be disastrous. If a view port came in direct contact with the vent fluid close to the hole it’s coming from it would easily melt it, flooding the sphere so fast you wouldn’t even know it happened. But it doesn’t have to get that close. If the fluid just softens it the 4000 PSI ocean pressure will finish the job. I used to joke around with the first time observers when they looked nervous and asked them to do a math problem to take their mind off it. How long would it take to fill a six foot sphere with water through a 4 inch hole at 6600 PSI? Kind of mean, I know but what can I say. I would then follow up by saying that if I thought I was going to die doing this I would find another line of work. I used to have a T shirt that said “I work well under pressure” and on the back it said “6600 PSI”.

I had 8 training dives to become a pilot. Most of them were in the Endeavor vent field. After learning to dive there, everything else was easy. Driving around those structures is a complicated and dangerous way to spend a day. I have been to all the major vent fields and the only thing that comes close to Endeavor is in the Indian Ocean. Endeavor is graduate level flying. It takes about 30 dives to be a cocky “I know my shit pilot”. That takes about 18 month of sea time to get that many dives.

As you cruise across the bottom there are many things for both the pilot and the observer to pay strict attention to. One very important rule is power consumption. The only power available for the dive is the batteries. When they run down to approximately 20 % the dive is over. Time to drop weights and head up. A dive can be short or long depending on a variety of things but the most common cause of a short dive in running out of juice. The battery tanks, there are 2 on board, are serviced on a 3 month rotating schedule. This ensures that one of them will be fresh. A recently serviced battery will have up to 40% more power available than a tank that is 3 months old. Then there is the holy grail of power consumption. All the observers are told in the initial briefing and throughout the dive that if they leave their lights on the whole time it will be a short dive. They always do but it’s because they don’t dive often enough to remember that kind of detail. Most observers will dive only once or twice in their lives. The pilot winds up sounding like a broken record; “turn off you’re light, turn off you’re light, turn off you’re light”. I can get so frustrating that the pilot winds up thinking “screw it. We’ll be home for lunch”. On a full battery charge, Alvin can cover over 10 kilometers in a day but leaving the lights on unnecessarily can shorten that to 6 klicks.

Driving over the bottom at 3 to 4 ft. can be tricky depending on terrain and speed but it’s the best height for making good scientific observations. The pilot however cannot see what is directly in front and below his window because of the sample basket. When sitting on the bottom He will often use the manipulators while looking out the observers windows.

Alvin has a forward looking sonar that works very well and can help with looking at the big picture, but when it comes to maneuvering around structures and rough bottom there’s nothing like seat of the pants flying. Sitting on the pilot’s chair, half kneeling against the hull, the pilot leans forward to put his face right in the four and a half inch window. With the forward lights blazing the visibility is about 60 to 70 feet in good detail but looming beyond could be a huge boulder or a cliff face. This is a world of complete darkness. The only light is what you bring with you. Most often yours is the first light to ever shine there.

The sub has enough forward speed that it’s easy to out drive your headlights. By that I mean you can get going so fast that if a wall appeared at the furthest reach of your vision you couldn’t stop in time. Been there, done that. Your only hope then is to drive up and try to get over it. Besides, if your going that fast the observers don’t get to look at any thing for a useful period of time. The bottom is just whizzing by. The word on that is to go slow and take it easy so they can toke good notes and pictures. If you have to go somewhere fast from point “A” to point “B”, it’s best to come up off the bottom a bit, say 10 meters and drive full speed using the sonar to avoid hitting anything. This way you can bring the sub up to full speed or about a knot and a half.

All this time submerged the pilot has readings on the atmosphere, leak detectors and electrical system to monitor every 30 minutes. A small mechanical timer is used to keep that regular. Sometimes the CO2 will creep up and one of the observers will complain of a headache. I never noticed. That’s about the only good thing smoking cigarettes ever did for me. I’d just tell them that they were breathing too much and were going to have to take shifts. All you have to do is speed up the blower motor on the can of Lithium Hydroxide to get the CO2 down. A little noisy but it works.

There has to be communication between the sub and the surface every 30 minutes. The pilot will do this when ever he check the atmosphere and leak detectors. This is usually done with the underwater telephone. This takes a bit of getting used to because of delay that’s a lot like making a telephone call through several satellites. The speed of sound through water is much slower that the speed of radio waves through air. Also there are several echoes of what is said due to the sound waves bouncing off thermal layers and even the surface. When you’re really busy sampling or driving through a rough spot there’s no time to turn around and pick up the microphone so the pilot will us a button mounted by the front window that acts like a Morse code key. If the surface controller called down at the 30 minute interval he will most likely send the letter “D”. As stated in the Alvin manual this means “What is your depth” He requires that information to accurately plot a position of the sub. The pilot will call up with that number or if bust send the letter “B” meaning on the bottom all is normal. This also implies that the subs depth has not changed since the last call. Other simple one letter queries and replies are essential when using a transponder net. The transponders use the same frequency range as the underwater telephone so if you talk in voice the water column will be filled with noise and there will be no position fixes from the transponder net for several minutes. Some of the other commands are the letter “V” for “give me a vector” or the letter “U” for “are you there?” “R” stands for “Roger”. There are others but these are the most commonly used.

All this has the pilot very busy from the time the bottom is in sight to dropping the weights to come home. When it came time for lunch the pilot will take a sandwich from one of the observers and eat it with one hand while driving with the other, face up against the view port. I always did the electricians post dive and part of that is cleaning up inside after a dive. The pilots “dashboard” would always be covered with bread crumbs. We heard that the French in the sub Nautille would stop and sit on the bottom to have lunch. They even had wine! We had water or black coffee.

Driving over the bottom is a fun, exiting and a real edge of the seat experience but there is no thrill bigger than getting up close and personal to use the arms for sampling. Alvin has two arms. One on the port side and one starboard. The port arm I used when I was a pilot is now in the exhibit center as a museum piece. This was delivered with the sub in 1964 as original equipment. It was old when I got there and didn’t get any younger. It was maintenance intensive and the overtime from working on that thing helped to but my first house. The starboard arm was everything the port arm was not. It had one more joint in the wrist and that was key. Also it was hydraulically powered and that made it very strong. It was the arm of choice to use for sampling. And if you did use it you wouldn’t be up all night working on it. After a day in the sub, you’re beat. Both of these arms were controlled by toggle switches. Once used to them I became quite skilled but these controls by today’s standard are so archaic it’s laughable. The modern arms on Alvin today are 7 function, specially correspondent, force feedback manipulators. In layman’s terms, they will mimic the movements of your own arm and allow you to “feel” what you’re grabbing, pushing or lifting. They have amazing dexterity making it possible for the pilot to carry out complex tasks that were never thought possible just a few years ago.

The front end of Alvin features the sample basket. It also acts as the front bumper. The frame is made of one and a half inch aluminum pipe and has a wire mesh basket on top to hold samples and tools. Under the frame is a 10 inch wide aluminum ski. Most often this is the only part of the sub to touch the bottom while flying along because the pilot will always have a bit of nose down attitude in order to see better over the basket. This puts the stern higher so that only the ski hits the mud unless you drive down on the lift props to sit hard on the bottom. “Hits” is a relative term. Many people think of the sub gracefully gliding over the bottom but more often than not that’s not the case and the sub has the scars to show for it. The great majority of Alvin’s work is done on the mid ocean ridges. This means hard rock and basalt everywhere. Alvin may be neutrally buoyant but driving forward it still has 18 tons of mass and does not stop quickly even when driving in full reverse. Add to that an inexperienced pilot who doesn’t get the sub quite neutral (they always err on the heavy side) and the sub will hit the bottom many times during a dive. I’m not the only one who’s come back with that aluminum ski pealed back and bent out of shape. That’s why there’s a couple of spares back on the ship. You can plan on being teased about it mercilessly. “How do you drive? By the braille method?”

When it’s time to leave the bottom the pilot will first secure all the tools and samples in the basket. If not done properly any item could wash out of the basket by the wave action on the surface or being towed through the water. When that’s all set he will call the Surface Controller and get clearance to come up. There are still two 250 lb. weights to drop. You release one and feel the sub heel over a bit confirming it dropped. When the second one goes the sub will heel the other way, now its sit and wait as the sub rises at about the same rate it went down. When you drop the weights you’re committed to going to the surface as the lift props do not have enough power to overcome that 500 lbs. of positive buoyancy.

His is the first time since launch that the pilot can relax a bit but there is still plenty to do on the way up. The first hour or so is spent labeling video and audio tapes, sorting notes and calling the surface to give a science report and a vehicle status report as every one topside is interested in how the day went and how much work there is to do that night. Getting Alvin on deck is definitely not the end of the days work, it only signals the start of the second half.

Approaching the surface is cool every time you do it. At 1000 meters you can look up through the little view port in the hatch and see the first glimmer of light. Looking out the front view port you won’t see light on the basket till 200 meters or so. Before the final approach to the surface to pilot and crew will have secured any loose items that could go flying around in rough seas. Depending on the sea state you begin to feel the motion about 50 meters from the surface. At 30 meters from the surface you can look up from the pilots view port and see the surface from the water side. A very welcome sight.

The Surface Controller will have given the pilot a heading to keep the sub on for recovery. While doing that he’s wearing the sound powered phone head set, waiting for the swimmers to come aboard and make contact while the sub bobs around in the waves. If you’re in tropical waters the inside of the sphere begins to heat up fast and layers of clothing are being shed fast. You can hear the whine of the small boats engine through the hull as it makes its approach and soon after the swimmers plug in and make contact. They will go about their business hooking up the basket safeties and tow bridle while often taking the time to moon the pilot at his view port 6 ft. under. Once the swimmers are done the ship will come by trailing the tow line behind it and so they can hook up and Alvin will be in tow. At this point the pilots’ job is just about done for the time being. Hauled in under the A-frame and lifted from the water he’ll wait till the Launch coordinator rinses the hatch with fresh water and then open up to some well earned fresh air. Due to the sphere being a bit cool and the rare at which the oxygen is used there can be a bit of a vacuum inside that will pop the ears when the hatch is opened.

The observers are of course the first ones out with the pilot last. In those days Jon would be waiting for me at the bottom of the ladder with a smoke and a light. There was the usual “Good job” and “Great dive” from the observers and it was off to dinner. Taking 30 minutes for that I would repair to the back deck for another butt and just like that went from pilot of the day to the electrician. I would spend any where from one hour or till midnight doing the post dive and fixing anything broken. And something was always broken.

The electricians post dive was fairly involved. It meant getting back inside and running all systems on the sub to ensure there was nothing broken and no surprises in the morning. That was part of it. The other part was to recover from having three people inside for 8 hours. The sphere is always in a state of disarray and had to be put back in order. As soon as I got situated I would call for a line to get all that stuff that was loaded in the morning out of there. The boys would stop doing there post dives to bear a hand. Since no one in the crew was standing by a radio, I would signal them by giving the ballast air a blow 3 quick times, a very loud and distinctive sound. The first thing out would be the used oxygen bottle and the last thing would be the HERE bottles. This stands for Human Element Range Extender. They were full of urine. Science was politely asked to empty their own. I however went to the Ralph Hollis School of submersible piloting. If you drank 5 or 6 beers the night before you would wake up dehydrated and didn’t have to pee all day.

The nastiest part of the electricians post dive was wiping out what we called “Lung Mung”. All the condensation from three people breathing in the sphere for 8 hours collects on the hull and eventually forms a puddle in the bottom of the sphere under the floor boards. It will total about two quarts in all and has to be whipped from the walls with a towel and sponged from the bilge to be squeeze into a bucket. You just keep telling yourself that it’s only distilled water. When that’s done the batteries are put on charge and the post dive is over. If you’re lucky you can knock off by 8 pm and catch the movie in the galley. Tomorrow it’s Surface Controller, then Launch Coordinator the next day followed by being Pilot again.