Safe to deliberately cause a free-flow reg?

[Dockmaster]

If you're going to hold down the purge button to vent the tank and you'll be in the safety of a pool, why not put the air to good use and practice breathing from a free-flowing reg under water? This skill is not practiced enough and is a good one to have in your bag of tricks.

 

[victor]

No risk of freezing - more a risk of sunburn! I'm in Malaysia.

Also, I'm 5" 10', 185lbs. Once I have my correct weighting in the pool with a 3mm suit, can any of you take a rough stab as to how much more weight I'll have to add for salty diving?

Thanks!

DeadLock
The 2.5% rule is good but I would add a bit of a safety factor to start. I am a bit heavier than you (mostly aroung the middle) but I don't wear a wet suit just a dive skin.
When I start a trip I am comfortable with 12 lbs, after about 4 to 5 dives I can reduce that to 10 lbs, and by the end of 2 weeks I am down to 8 lb's and slightly negative at that. Part of this is that my breathing has improved and I can choose to breathe either with half full lungs or mostly empty lungs, this makes a huge difference in your buoyancy.

Remember you can always add a little air if you are negative.
If you find you are positive then ask the DM for a weight or look for a decent sized rock and put it in your pocket (note rock not coral).

Where are you going to dive?

 

[dkktsunami]

No risk of freezing - more a risk of sunburn! I'm in Malaysia.

Also, I'm 5" 10', 185lbs. Once I have my correct weighting in the pool with a 3mm suit, can any of you take a rough stab as to how much more weight I'll have to add for salty diving?

Thanks!

6 lbs.

 

[imwright1985]

just do it with a full tank then add depending on the tank some extra weight, an al80 runs between 4-5 lbs, there are charts that have a general breakdown by mgf and are within about 1/2 a lb +/-.

 

[halocline]

And performing a weight check with a full tank is fine too and it comes pretty darn close to performing a weight check with a near empty tank.

Actually there is a 5-6lb difference depending on the size of the tank. Bleeding the tank down with the regulator under water is probably better than doing so on land, as the water will act as a pretty efficient heat sink and keep the valve and reg from getting too cold.

I agree that 500PSI is probably a better pressure at which to do a weight check than almost empty.

 

[Damselfish]

The point is to weight so you're neutral with an empty tank, not necessarily to do the check on an empty tank. But somehow a lot of divers are stuck on the idea of doing a weight check when the tank is empty, when doing it full then adding the buoyancy swing of the tank works as well - and is often a lot more convenient in the real world.
You can follow a formula to go from fresh to salt, but figure on checking it again anyway.

Even if it's not terribly unsafe to run the tank down to 100 psi in a pool, no point in chancing running it out because your gauge is off, which happens. Why risk getting water in the tank? If you return a tank empty they tend to get cranky and want you to pay for a VIP.

 

[herman]

Even if it's not terribly unsafe to run the tank down to 100 psi in a pool, no point in chancing running it out because your gauge is off, which happens. Why risk getting water in the tank? If you return a tank empty they tend to get cranky and want you to pay for a VIP.

Actually, it's a good idea to totally use up a tank from time to time, just to see what a real OOA actually feels like. It's nothing like the closed air drill they do in class. I do it a lot of times when I have a tank needing vis, somebody has to drain it, might as well be me....I ALWAYS do it in a safe place and know full well what to expect, like 5 ft from shore in 6 ft of water at the quarry- never on a "real" dive. In addition, finding out your gauge is off by a few hundred pounds on the low end of the scale is not a bad thing either. The risk of getting water into the tank is nothing more than an old wifes tale. You really really have to work to get the tank pressure down to less than 30 psi or so and even if you get it to zero, you have to remove the reg and submerge the tank before water can get in. Don't worry about the VIP either, I have yet to see a tank monkey check the pressure on a tank before filling it....it's hard enough to get some of them to check it afterwards.