Just out of curiosity, what "range" do you consider acceptable for a stop depth.
A bit of background. I make a dive once ever other week or so with a buddy that involves the following exercise.
The first 1/2 of the dive we descend along a sloping bottom to anywhere between 33 and 38 metres depending on the day. The swim out is usually 20-25 minutes depending on depth. The computer usually shows running out of no-deco time about where we turn the dive (few min before or after). During the swim back we'll go part way over the bottom and then make an ascent to mid water so as not to accumulate too much deco-time and then hit our stops while free swimming. This is all done with zero visual reference because our viz is limited to about 3 metres. It's also sometimes done in the dark. The tasks are split so one of us controls stop depths and uses his body and light-beam to create a visual cue for depth and the other controls navigation.
We both have pretty good buoyancy control and over time we've developed much tighter control over this manner of ascent. We deliberately don't use a DSMB for reference because it would defeat the purpose of the exercise. Deco usually clears by the 9 metre stop according to the computer but the dive plan includes about 10-12 minutes at 6m because it takes that long to swim back to the point that we re-encounter the bottom again. The last part of the dive is usually another 8-10 min--give or take--from 6 metres and up and we'll surface after 45 or 50 minutes.
We're doing this strictly as a skills exercise to practice making clean stops and navigating accurately using nothing but instruments. We've probably made 50 dives like this since we started with it and I'd say we're getting pretty good at it.
Here's the thing. You can never nail your stop with centimeter accuracy. The best I can realistically manage on a "good" stop is probably a bandwidth of about 30cm (+/- 15cm) and that requires pretty much not taking my eyes off the depth. 1/2 metre (+/- 25cm) is more like the norm.
So for people who do something similar, what target do you set for yourself in terms of depth variation for holding stops and what do you normally achieve in reality?
R..
P.S. if you're prone to one-upmanship I would appreciate it if you could wait until the people who actually do these kinds of dives answer first. We all know that you can hold a stop to millimeter precision behind a keyboard. I'd like to first hear from people who do this on a regular basis. Okthx.
R..
A bit of background. I make a dive once ever other week or so with a buddy that involves the following exercise.
The first 1/2 of the dive we descend along a sloping bottom to anywhere between 33 and 38 metres depending on the day. The swim out is usually 20-25 minutes depending on depth. The computer usually shows running out of no-deco time about where we turn the dive (few min before or after). During the swim back we'll go part way over the bottom and then make an ascent to mid water so as not to accumulate too much deco-time and then hit our stops while free swimming. This is all done with zero visual reference because our viz is limited to about 3 metres. It's also sometimes done in the dark. The tasks are split so one of us controls stop depths and uses his body and light-beam to create a visual cue for depth and the other controls navigation.
We both have pretty good buoyancy control and over time we've developed much tighter control over this manner of ascent. We deliberately don't use a DSMB for reference because it would defeat the purpose of the exercise. Deco usually clears by the 9 metre stop according to the computer but the dive plan includes about 10-12 minutes at 6m because it takes that long to swim back to the point that we re-encounter the bottom again. The last part of the dive is usually another 8-10 min--give or take--from 6 metres and up and we'll surface after 45 or 50 minutes.
We're doing this strictly as a skills exercise to practice making clean stops and navigating accurately using nothing but instruments. We've probably made 50 dives like this since we started with it and I'd say we're getting pretty good at it.
Here's the thing. You can never nail your stop with centimeter accuracy. The best I can realistically manage on a "good" stop is probably a bandwidth of about 30cm (+/- 15cm) and that requires pretty much not taking my eyes off the depth. 1/2 metre (+/- 25cm) is more like the norm.
So for people who do something similar, what target do you set for yourself in terms of depth variation for holding stops and what do you normally achieve in reality?
R..
P.S. if you're prone to one-upmanship I would appreciate it if you could wait until the people who actually do these kinds of dives answer first. We all know that you can hold a stop to millimeter precision behind a keyboard. I'd like to first hear from people who do this on a regular basis. Okthx.
R..
