SCUBA Regulator for speeds at 3 to 4 knots

[Nwcid]

The inline adjustment tool is a little overkill unless he also has a magnehelic and knows what cracking pressure he needs.

I think a screwdriver or hex key would be sufficient.

Being able to adjust while it is actually hooked up makes things a lot easier. It only takes very small adjustment to make a big difference. The inline makes micro adjustments very easy.

I had one regulator that had a different size fitting and tried to adjust it without the tool. I never did get it quite right right. The company did send me the newer style in the standard 5mm size. Hooked to pressure I was able to adjust the rest fine and have never had a problem.

 

[rhwestfall]

but without a MAG (or a manometer), as stated prior, you are still taking shots in the dark..... possibly micro-sized ones, but still w/o any useful basis...

 

[redacted]

Have you considered some front cover reinforcement. Perhaps some inner tube would provide enough protection without blocking the purge

 

[diversteve]

What about a Hollis 500SE. It presents a smaller than normal front cover to the water column streaming by. 500SE SECOND STAGE

 

[tbone1004]

same as oceanic omega 3, but the there isn't a "front" cover since it is actually on the back. Lots of reports of them freeflowing so I would consider that a second option behind the Xstream

 

[REVAN]

Thanks for the ideas. Of what I've seen here, the ScubaPro regs look like the best configuration for my application. It's too bad they are not making regs of that type any more. Maybe I'll find one for sale used. If not, I'll take a closer look at the Xstream this year at DEMA.

Which dpv are you using where you can get up to 4 knots, and how are you sustaining it? I'm not aware of any dpv's that are able to go over 3 knots, and that is both painful and exhausting....

I'm making a custom setup, experimental and presently without a name. The testing is difficult because the reg starts freeflowing long before I can test the legs of this contraption. I may try to make some kind of shield for the front of the reg. Presently, I just need something that works well enough to do my engineering and testing. If I get everything working well enough to use outside of a test environment, then I'll be interested in spending whatever I need to spend to get an optimized regulator.

From other's experiences, is a typical regulator like the SEA-4 "adjusted for scooter diving" expected to start freeflowing between 2 and 2.5 knots? Does anyone think that the problem is just an adjustment setting with this regulator that I should be looking into more closely?

My regulator does not have an adjustment knob on it. There is a plastic cap with a hex hole in it to unscrew the cap. Removed, there is a small screw down under there close to the center of the reg. I'm thinking that may be what adjusts the cracking pressure. I gave it a twist, but it feels about the same breathing from the regulator out of water. I don't really know how sensitive it is. I'll test it in the pool later and see if there is any difference.

 

[tbone1004]

conveniently one knot is about 100 fpm, so in normal scooter speeds, the high end ones are able to get up to close to 300fpm or 3 knots. The standard scubapro style second stage, which the SEA-4 is, shouldn't freeflow at those speeds unless your are facing directly into the current. Most people are using those style second stages on dpv's in the 2-3 knot range.

Adjusting is typically the lever height adjustment which requires removing the hose and adjusting the hex in the regulator inlet portion. Frogkick.dk should have the manual for adjusting if you're comfortable doing it

 

[underH2Oman]

I agree that it could be adjusted to reduce or eliminate flowing in the current, but we all enjoy an easy breathing regulator. Alternately you need to prevent the water from pushing the diaphragm in. I believe the SEA 4 has several slots in the plastic cover. When facing into the current the water is being forced into these and depressing the diaphragm. If these openings were smaller you would not have the water force on the diaphragm. Red Green would pull out a roll of duct tape and cover 90 % of the opening and wallah problem solved.

 

[USdiver1]

. Red Green would pull out a roll of duct tape and cover 90 % of the opening and wallah problem solved.

+1 on Red Green's use of the "handyman's secret weapon".

 

[guyharrisonphoto]

Revan,

I second the xtream. The design places the purge to the side and facing a little towards the back. There is no way a current is going to make it free flow. Nothing like what you are planning, but I have dived it holding fast to a wreck in 2 knots in Jupiter (a miserable dive) and no hint of free flow. As a bonus, it needs no knobs or levers to fiddle with breathing resistance, is about the best breathing reg out there once you get used to it, and hasno bubble interference (although that won't be an issue if you are moving 3 knots!).