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.Inflatable Water Slide 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.