Archive for August, 2008

Back to the Bidevind on the Independence II, August 17

Sunday, August 17th, 2008

Our initial destination was the Texas Tower. We left port with a boat full of rebreathers, and a pair of open circuit divers. As fate would have it, we ended up on the Bidevind. The trip out had been fairly calm with seas around 3 ft. Since Bill and I were going to tie in, we were relieved of bridge duty for the night. When the boat neared the wreck we started to get ourselves together. I was trying out my new Liquavision X1 with V-planner live. Bill uses an HS Explorer with integrated RGBM. It was to be the battle of the bubble models.

When we hit the water, we could see the line hanging directly below the ball. The surface vis was great with no current. We dropped down quickly through the clear blue water. I noted a thermocline at 70′, and the temperature slowly dropped below that. The vis dropped off slowly, but was still good, with lots of light. Soon we could see the rope coiled below us on the sand. This means two things: first the vis was great (about 50 ft), and second, there was no current. Bill headed off over the wreck looking for a spot to tie off. I headed for the shot to send it back up. When I reached for it, I noticed that the nice shiny shot and chain had apparently caught the attention of a lobster which was now out of it’s hole, and on top of the shot. Well priorities are what they are, so I’ll have to come back for him later.

We were quickly tied in, and along the keel. With the ambient light, navigation was a snap. The last time we had been here, I took the scenic tour. This time, I was here to have fun. We headed out along the wreck picking up lobster after lobster. Bill had coxed a pair of 4 pounders out of their holes. One of equal size had evaded him. I was mostly bagging, but was able to grab a few of my own. Some of them were just walking about. We made it back to the props, then turned back toward the bow. Here and there were medium size monkfish lying on the bottom. While I was tempted to grab one, I had not brought my spear, and my line cutter was not going to do the trick. At one point Bill pointed out a huge flat fish. It did not have the markings of a Fluke, but did have a large mouth. By the size, I was wondering if it was a Halibut. Again, the available weapons were not up to the task at hand, and I’ve been chastised ever since.

We were quite warm as the bottom temp was 48 degrees. After 45 minutes, we really didn’t want to end the dive, but given our current deco obligations, our bailout would not permit us to stay longer. Also, the rest of the crew would not be able to get into the water until we got out, so we headed back to the line for the long ascent. On the way Bill headed out into the sand and grabbed a few scallops. On the way up we quickly hit the first thermocline and remained warm the whole way. There was a layer below the 70′ thermocline which was a bit cloudy. While hanging here, we looked up to see a large creature swim by. Neither one of us saw the front, but the tail was definitely that of a shark. What type, we could not say. There was no lateral line, and the body was uniformly speckled. The size was at least 8-10 ft, and the distance from us was more like 6-8. We kept looking around for him to return, but did not see it again. Above 70′ the vis opened up to close to 100′. We could see the back of the boat from the anchor line. At this point divers started dropping down the line by us. The first was using a scooter, then one by one the rest headed down. A couple of them had already boarded the boat by the time Bill and I finished our obligation.

When we hit the surface, all the passengers had entered the water, and the crew was now jumping in. We didn’t have time to mention the shark, but they did see the bag full of lobster.

When they all returned, we talked about the wreck, and what everyone had seen. Several other divers mentioned seeing a school of sharks. One diver was taking video, while the scooter diver was able to make several passes around the wreck. Brandon went in with his camera, and got some great shots. Terry brought up a few lobsters to add to the cooler. Due to the distance from shore, the crew had opted to do one long dive, but the passengers all did two. On the way home everyone talked about the great dive and the fantastic conditions. It just doesn’t get much better than this.

(Photos on this article by Brandon McWilliams. Check his Blog here)

A new skill for the toolkit

Sunday, August 3rd, 2008

Given the events of this week, I decided to add a new skill to our class. Sherwood, John and I practiced the infamous “use a lift bag as backup buoyancy”. The plan was to find a platform at the end of our dive then dump our BCs and inflate a lift bag to execute a controlled ascent (with simulated deco).

The plan started to fall apart when someone moved the platform. Either that or my navigation on the east side of the lake leaves a lot to be desired. After an hour of dragging the guys around to places and attractions we will never find again, we just picked a spot in about 70ft of water and tried the drill. Let’s just say, it takes some practice, and we have no idea who silted up the bottom.

Had we started from a platform kneeling, it may have been much simpler. Sherwood probably had the best idea of dumping the air from the wing into the bag (there by remaining neutral). While a great idea, he later admitted the execution needs a little practice.

My attempt was nearly thwarted by the anemic performance of my second stage purge. While the reg delivers copious amounts of air on demand, the purge only generates a trickle. After dumping my BC, I had to lay on the purge waiting for enough lift to stop my downward plummet. Fortunately this occurred just feet from the bottom. I was just a few feet from the indignity of a full face plant in the silt. Clearly I could have added air back into my BC, but for some reason, that thought never entered my mind.

After a few moments we gained control of our buoyancy, and began our ascent. We were able to execute our simulated deco, and surface with surprising control over ascent rates. We did all this in a free ascent with no visual reference.

Many of us discuss this skill as an option in the event of BC failure, but how many times do we actually practice it. The next time you’re at Dutch I suggest giving it a try, and add another skill to your tool kit. I just wanted to add some thoughts to keep in mind. A 100 lb lift bag is not designed for the minute buoyancy adjustment we make with our BC. Be very careful with the dump. It can release a lot of gas quickly, and you’ll be headed back down again. When practicing, do NOT attach the bag to yourself. Just hold it. If you lose control of the ascent, you can let go of the bag, and add air back into your BC.

Kudos to John and Sherwood for pulling off this impromptu skill.