- Reaction score
- Boulder, CO
- # of dives
- 1000 - 2499
I wasn't lumping them together. Truly open bottom will spill at a moment's notice and should be avoided like the plague.I just don't know if they were including the "semi closed" duck bill style ones in their definition of "open bottom"
In my view, the duck-bill / semi-closed are OK but a bit unnecessary. (An inflator hose will do the job if you lack the lungs/depth to properly deploy orally, which admittedly will happen at some point as size increases.) However, the market seems to disagree with me given the proliferation of semi-closed in larger sizes.
As I understand it, the main drawback to semi-closed is water can be forced up through the duck-bill valve in some situations. I suppose freeflowing a regulator (the typical way I've seen them deployed) could be a risk in cold water, but I'm speculating there.
I don't feel strongly about the duck-bills, though, and I mentioned up-thread that I have one. However that's only because I can't find an affordable closed-style in the size I'd like. So I just treat the duck-bill like it was closed... and carry a (smaller) closed one as backup.