What a difference a (new) BC makes!

I recently bought a new BC because I wanted something less bulky and lighter for travel. I'm not starting this thread as a place to praise or bash one style or another, I just want to share my experience of how the equipment you use can make a difference.

I've been diving an Oceanic Probe (jacket-style, lots of pockets) for several years, but recently decided to look for something a little travel-friendly. Size was the first consideration, but weight was also a factor. I ended up with an Aeris 5 Oceans (back inflate), which was about 3 pounds lighter and packed much smaller, which was on clearance at my LDS. I took it with me on a recent trip to Saba. I realized two things: One, when you use a lighter BC, you need to compensate with more weight. Not rocket science, but it only dawned on me after the first couple of dives. Second, after several dives, I realized that the reason I was getting about 10 minutes longer down on each tank than I had in December was probably the new BC.

So I guess the moral of this post is that when evaluating equipment, if you can try before you buy, remember to look at your overall performance, not just how it feels and what doodads it includes.

Isn’t it possible your need for more weight was from some cause other than a lighter BC? The three pound difference in BC weight was probably offset by less overall volume.

Some other candidate causes:
- different wetsuit
- change in body mass
- salinity
- air trapped in BC (ok, that’s BC related, but not the weight of the BC)
- change in breathing pattern
- etc.


And there are several variables associated with dive duration. I don’t see why a different BC would directly affect the length of your dive.

Other considerations:
- dive profiles (the mother of all variables)
- your increased experience/comfort level
- how hard you were working on the dives
- etc.

I would actually expect less weight required. With a larger BC with more features often comes more padding and more buoyancy to the BC. So a smaller BC with less features and padding would be less buoyant and require less weight.

I agree; some are likely, others not so much. Both sets of dives were off Saba. December was a 1mm full suit and 3/2 shorty; April was 3 mm fullsuit. Body weight about the same. Dive profiles were varied on both trips, but the increase in bottom time was fairly consistent over both deep and shallow profiles. No dives in between the trips, so experience level about the same.

And you are right that there is more involved than 3 lb lighter BC = 3 lb more lead, but I can't see how it is NOT a factor.

I should also note that my bottom times had been pretty consistent for many dives before the new BC, including with the same wetsuit I was wearing. I think that the most likely thing is that the new BC gave me a smaller profile and the reduced drag let me move with less effort, especially against current or surge.

I agree with the theory of Try before you Buy. That said, honestly, I have found that very difficult to actually do. Unless you have unlimited access to various BCD's with unlimited use - I honestly don't feel a single dip in the pool warrants enough feedback to evaluate the BCD. My LDS allows for a try/buy kind of deal, but its really limits use. Just my 2 cents.

kerrycorcoran:

I agree with the theory of Try before you Buy. That said, honestly, I have found that very difficult to actually do. Unless you have unlimited access to various BCD's with unlimited use - I honestly don't feel a single dip in the pool warrants enough feedback to evaluate the BCD. My LDS allows for a try/buy kind of deal, but its really limits use. Just my 2 cents.

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I agree, that is a major drawback. And rental BCs don't offer a lot of diversity. I guess I would suggest that if you are in a dive club, ask other members if they are willing to let you try their gear.