My brother Ralph wears a knee brace to protect a messed up knee joint. He was wearing it while water skiing on Lake Mendocino a few weeks ago, and lost it in the water. One of his friends dove down and claimed to touch the bottom at twenty or thirty feet, but could find it. Ralph asked Paul and I if we were interested in diving down to try and find it with SCUBA gear. We agreed to do it just because doing a SCUBA salvage job sounded interesting. We got together on Saturday morning and drove out to the lake.
The water at the shore of Lake Mendocino was cloudy at the surface, but looked like it had four or five feet of visibility. Paul and I have found abalone in visibility worse than this, so it looked possible. Ralph drove his motor boat out the area where he believed the brace went down, which looked reasonably close to shore. Paul and I swam out with all our gear on and Jeremy (Ralph's son) followed us in a kayak. Before we got out to where Ralph was waiting, Paul and I started to drop down to find the bottom. To our surprise we fell to sixty feet before we found the bottom. "Found" was not the correct term, since light did not penetrate below forty feet in this murky water. We dropped into total darkness in the middle of the day. With no references I fell with runaway negative buoyancy and didn't stop until I sank a meter into the soft slimy mud on the bottom. I tried putting some air in my buoyancy compensator (BC) and was horrified at how much air it took to get neutral. It took so much air I began to wonder if the BC could even lift me out of the mud. For a while I thought I was going to leave my weight belt behind.
Since we had been told to expect twenty or thirty feet, we had considered not bringing flashlights at all. Paul had a small backup flashlight, and I had felt foolish sticking my medium sized flashlight in the pocket of my BC. Lying almost face down in the mud I felt around in the darkness and got this flashlight out of the pocket and turned it on. I was surrounded by a cloud of brown mud I had stirred up and could hardly see the flashlight from several feet away. I found my pressure gauge and by holding it and the flashlight inches from my face I read for the first time how deep I really was. Sixty feet! With visibility less than a foot, no sunlight to see by, and water this deep, there was no way we were going to find Ralph's brace.
By the time I got my buoyancy under control Paul had found me by the light of my flashlight. His little flashlight could barely put out a dim brown glow and I could never have found him. Paul had the compass and he lead us off in a search pattern. I found out later that Paul had concluded from our depth that we were too far out and would find shallower water closer to shore. However, we found a fairly flat bottom that stayed sixty feet deep everywhere. Up on the surface, Ralph and Jeremy followed us in frustration as we went the wrong way then went around in circles. Down on the bottom, we discovered that I could see a few feet in both directions by waving my flashlight back and forth. Paul led us in a search pattern by watching his computer console, which had a clock and compass mounted close together. He followed the course but did not have a flashlight to search with, that was my job.
The bottom was covered with silt, but we did find some items down there. We collected three golf balls. I saw a large tackle box but left it where it was. We saw a few branches on the mud and ran into a few trees still standing on the bottom. As we paddled around in Paul's search pattern we would occasionally cross over our path. I recognized prints in the mud where my own hand had pushed off the bottom on a previous pass. All this gave me some hope that we could find the brace, but we ran low on air without seeing it. When my pressure gauge got down to 600 pounds, I showed it to Paul and he agreed to go up.
But as soon as I pushed off the bottom I started a runaway buoyant ascent, the opposite of the problem I had on the way down. I have never been comfortable controlling my buoyancy and need to practice doing this a lot more. When I saw I was rising too fast, I first turned head down to try and hold my position by swimming with my flippers. But the BC is designed to vent air while turned head up so I had to turn over again. For a while I stayed in the rising stream of bubbles from Paul. I lost my grip on the vent tube of the BC, then knocked my regulator out of my mouth. I chose to find the regulator first, and look for the BC vent tube later. Probably the wrong decision since by the time I was organized again I was rising faster than ever. I broke the surface long before Paul did. When he arrived we talked about it and I decided to go back down to fifteen feet, find a spot near shore where I could sit on the bottom, and stay there for a while as a precautionary decompression. My tank only had a few hundred pounds left, and I sucked it all the way down to the peg before I left the water.
When we got out, we found a golfer teeing up to drive a couple dozen balls into the lake. I asked him how many of these balls he thought might be hit onto the lake in a week. He replied that he personally knocked almost two hundred in every week! I told this to Ralph and suggested that if we only found three out of two hundred golf balls in the water, the chance of finding one leg brace was vanishingly small.
We rested, out-gassed nitrogen for an hour and a half, and talked to Ralph. He figured that we had landed in a deep channel and his brace was farther from shore in shallower water. I sent him back out in his motor boat to plumb the bottom with a lead weight on a line. With a forty-foot line, Ralph was unable to find the bottom at all. Paul recalled that the bottom had been incredibly flat everywhere we had been, everyone had noticed the steep drop-off at the shore, and I could confirm that the bottom continued very steep at the fifteen foot level where I decompressed. We decided that the bottom must really be sixty feet deep and started planning our next dive accordingly.
This time I had Jeremy hang the lead-weighted line off the side of the kayak. As we descended we had this to hold onto with one hand as we adjusted buoyancy with the other. With something to grab onto I was able to control my buoyancy on the way down. We paused at the end of the line and made sure our flashlights were on, then went to the bottom. As before, Paul lead the way without doing any searching himself and I waved my big flashlight back and forth just above the bottom. We found a few more golf balls, and a deeper channel that took us down to seventy feet on this trip. Occasionally I would plow head first into a ridge of mud on the bottom before realizing I should swim up over it. I would loose sight of Paul from time to time and have to spend time finding him again. When spending all my efforts looking for or keeping up with Paul I didn't do a good job of watching the bottom. I figured that I could swim directly over the leg brace and not notice it. I would get the barest glimpse of Paul's tank from some incredible distance, like ten feet away. My instinctive reaction was to keep my eye glued on that glimmer and swim faster to catch up. But I forced myself to pan the flashlight back and forth over the bottom while swimming half blind in what I guessed was the right direction. It didn't help, we still did not find Ralph's brace.
We stumbled into a little grove of dead trees. Paul went left around one side of a stump and I went the other way. Paul ran into some fishing line running between branches and was worried about getting tangled. I ran into a bunch of branches and went over them. Paul saw me above the branches but lost sight of me. When I got back down to the bottom away from the trees, I could not see Paul anywhere. I waited for him to find my flashlight but I was in the center of a dark cloud we had kicked up. I tried decreasing my buoyancy so I could stand on the bottom and wave my light around. Paul never saw it even though we were probably only ten or fifteen feet apart. By then I was low on air again so I started up. This time I arranged my gauges and flashlight in front of my face in my right hand, and got a firm grip on the vent tube with my left. I managed to do a better job of slowly rising to the surface. My buoyancy oscillated between too positive and too negative, but I managed to ride it. When I oscillated towards too negative, I would start to sink again and I realized I had two poor choices: My pressure gauge was down below 300 pounds and I didn't want to waste it re-filling my BC. But the other option was to swim myself up against the negative buoyancy, working harder and using up air faster!
At around fifteen feet, I ran into Paul waiting for me. He had made it to the surface first this time and followed my bubbles back down again. I tried to wait there for a safety stop, but my buoyancy oscillated up and down. For fear that I would run out of air to re-fill the BC on a downswing, I continued up to the surface. Paul found the whole experience "spooky" and says that he is through with ever diving in fresh water lakes again. I begged Ralph: "Boss, don't make me go down there no more!" But we had used up all our full tanks and could not continue even if we felt like it.