HOME | Scuba! | Masks | Snorkels | Fins | Suits | BCs | Tanks | Regulators | Instruments | Physics | Physiology | Safety | Animals | Places | About us

« April 2010 | Main | June 2010 »

May 03, 2010

Experimenting with dive gear

When I first took my certification classes a few short (it seems) years ago, I had absolutely no idea what kind of gear to buy. So I asked for expert advice and bought my first snorkel, pair of fins, mask and boots list in hand. It was good advice as, 133 dives later, I am still using that exact same set of gear. In fact, I am also still using the same BC, regulator and dive computer.

This, however, does not mean I'm not experimenting with dive gear. That's because while you get used to your gear, it's certain to have some annoyances and inadequacies you'll never get used to, and if you're the inquisitive type you'll also feel a strong urge to try out whatever new stuff the dive industry comes up with each year.

The first thing I started experimenting with was masks. That's because an ill-fitting mask can make you miserable, and because masks are inexpensive enough so that picking one up every now and then won't break the bank. I probably bought half a dozen masks to find out for myself how split lenses work versus a single lens, whether masks with panoramic side windows can improve peripheral vision, whether masks with a larger lens can reduce the sense of tunnel vision you can get with small lens masks, whether purge valves work, and whether there's much of a difference between clear silicon skirts and opaque ones.

In the process I found that my original mask worked best for me and the only thing I liked better was the same shape and design, but with a clear skirt. I also learned to never use a new mask on a real dive without making absolutely certain that whatever protective coating the manufacturer applied to the lens had thoroughly been removed, and that finding the right anti-fog is worth its weight in gold.

Experimenting with gear also showed me that I need dive boots with rigid soles because I inevitably get cramps in my feet when I use boots with lighter, more pliable soles. And that, for me at least, having a regulator mouth piece that fits just right is a must unless I want to suffer through three quarters of every dive, with a hard, recalcitrant mouthpiece loosely between my lips.

Unfortunately, trying out dive gear isn't always easy. Sure, you can put on gloves and see how they fit, but you won't know how well they truly work for you until you wear them on a real dive and see if you can still operate your dive computer at 100 feet when the water is really cold. And trying out a new dive computer means you have to find a shop who'll let you try it (not so likely with expensive new gear).

Of my original gear, my first wetsuit was first to be replaced; it was simply too hard to put on, and being a size medium on a medium-tall body, its arms and legs were too short. I knew about the arms and legs when I bought it, but I'd simply not had the will to try on another in sweltering heat. And I had not knowd that I'd literally end up hurting my hands and fingers from wrestling with the thing on real dives. Only experimenting with several other wetsuits showed me the (for me) proper balance between elasticity, size and design that made a suit do its job while still being comfortable and reasonably easy to put on. In essence, if it's too tight you're miserable. If it's too loose water will slosh in and you get cold.

There's also another aspect of wetsuits to consider: how easy they are to pull down when you need to pee! That's one of those things no one talks about, but every diver knows what it feels like when you suddenly know you have to go five minutes before a dive, or when you come up from a dive and badly need to go in the tiny head (boat speak for bathroom) of a crowded dive boat. Why wetsuits don't have zippers is beyond me. So when my local dive shop had a special sale on shorties with a whole body zipper, I picked one up for a song. These shorties are actually meant to be worn over a thick wetsuit and they have a built-in hood. But I figured they might also come in handy in warm water without wearing a wetsuit underneath.

So I decided to try gear in the pool in 64 degree water. I wore the shorty just over a bathing suit and it worked exceptionally well. It was a bit too large to keep water from coming in, but it still kept my torso and head nice and warm, and it was super-easy to put on and take off. So I bought a second one a size smaller so I have one for its original purpose (to be worn for extra warmth over a thick wetsuit, and one for use in warm water for convenience).

The primary reason for the pool test session, however, was trying out the SpareAir bottle Carol had given me as a Christmas present. There's plenty of debate on whether it makes sense to take a pony bottle on a dive and I wrote about it in an earlier entry. For me, though, the fact is that I often find myself diving and suddenly being very aware that it'd be a really bad thing if something were to happen to my air supply. I look at my dive buddy or the closest diver and wonder if I could actually get to them in time should something happen. You can't holler to people underwater if something goes wrong, and you can't move very fast. Add to that the fact that if the next breath out of a tank doesn't come, you're already in need of a breath, and the thought is quite scary. So I always felt redundancy in the form of a small pony bottle made sense.

My SpareAir is a small yellow bottle a bit over a foot long, including the second stage and mouth piece that's part of it. Pressurized to 3,000 psi, the little bottle holds three cubic foot. The Spare Air package comes with a yoke adapter that lets you fill the SpareAir from a regular scuba tank (you can, of course, also have it filled at a dive shop). But how easy is it to fill the bottle yourself, and how long will it actually last underwater?

Filling it is easy. The SpareAir has a thread for the supplied yoke adapter. You screw that into the SpareAir, then attach the yoke to your scuba tank the exact same way you put on the regulator. You then slowly open the air valve on the tank to start filling the SpareAir. There is no pressure gauge on the SpareAir. Instead, there is a small adapter with a bolt that sits in a groove. Pressure pushes the bolt out, and you know the bottle is filled to its rated capacity of 3,000 psi when the bolt is flush with the surface of the screw. Imprecise for sure, but it will give you an approximate reading on how much air is in the bottle.

Which isn't much. Three cubic foot is just about 1/27th of the content of a standard 80 cubic foot tank. So if one of those tanks lasts me anywhere from 45 minutes to 75 minutes, depending on depth, water temperature, and stress, the SpareAir would theoretically provide an additional two or three minutes.

Before you take a SpareAir along, you need to figure out where to mount it. Scuba gear is infuriatingly bulky as it is, and adding anything only serves to further increase your drag (and stuff that can fall off or get you snagged). The SpareAir documentation shows several ways to attach the bottle in its yellow canvas case to your gear. It's small enough to fit about anywhere, so I ended up clipping it onto my chest.

A the bottom of the pool I removed the SpareAir from its case (easy enough) and began breathing from it. First impression: damn, that goes hard! But air did come out, and after a few breaths it almost seemed normal. I sat and slowly swam around, holding the bottle in my hand. It's actually about neutrally buoyant and you can swim with it without holding it. I was wondering if having to suck this hard would contribute to panic in an emergency situation, but probably not; at least there is air.

With each consecutive breath I wondered how long the little bottle would hold out, and what would happen when it was empty. Ten, twenty, thirty breaths, and no difference. I also looked at the time on my dive computer. I figured I normally take between six and ten breaths a minute. 40 breaths, and there was still air and I did't have to suck harder. It finally gave out at 50, and I had been on the Spare Air for five or six minutes.

Now using the SpareAir in a pool at seven feet is one thing, using it on a real dive another. Air that lasts 50 breaths would only last 15 or so at 100 feet or 25 at 30 feet. And that's not taking into consideration panic or having to work hard. But the little bottle does work, and if push comes to shove, having a few more breaths to figure out what to do seems a whole lot better than having none.

Posted by conradb212 at 03:42 PM | Comments (0)