Quote:
| Originally Posted by Digger ...add some more air depending on depth. If you're miles down, just put in a bit to get it on its way. If you're at 6m, you're going to need to fire in a fair bit to get it full at the surface. |
A totally full DSMB is slightly, but not that much more visible than a part-inflated one. I used to try to fully inflate the DSMB each time, until Andy Kerslake asked me "why?" on Fundamentals.
If using a "fill by demand valve" DSMB, I'd add the air slowly, and stop before it gets more than you can keep down by swimming down/breathing out. This let's you check everything is squared away just prior to release, rather than filling the DSMB quite full, and needing to hope that nothing's caught. This would be unlikely to leave it full at the surface, but makes for a safer deployment.
I now use the small closed circuit Halcyon DSMB. This is approx 3L? volume. It's so easy to fill by exhaling into the valve, that I don't bother to use the direct feed. A good breath as shallow as 3m will have the DSMB fully inflated at the surface. They are about 1/2 the width of a standard DSMB, and about 3ft long. I know a couple of others with these DSMBs, and we've never had problems with surface cover spotting/tracking them.
David