Mini Scuba Tanks

[dtfeld]

I've been seeing small refillable scuba tanks on various sites. Typically .5l-1l and good for about 5-10 minutes. I was thinking of adding one for allowing inspection under the boat, and unwrapping lines around the shaft. Free diving about wore my ass out the last time I had to cut a wrapped line.

Obviously there are safety concerns with this stuff, but somebody has to have tried or is using these for what I've described.

Pros/Cons or recommendations?

 

[ttmott]

I have a small bottle I use. It's called a Spare Air. It's good for probably five or six minutes depending upon depth. Never had to use it however. It is filled from a standard scuba tank. The mouth piece is on the tank so it isn't very utilitarian as you have to keep a hand on it.
I've never seen the systems filled with a hand pump - interesting....

 

[Skybolt]

Interesting I had no idea this was available. Definitely a possibility for cutting a line off. If something goes wrong you don't have far to go to pop your head up and get air. Can't see this as a bad thing.

You could always try it out in your living room first and see how that goes.

 

[Skybolt]

This looks like the perfect answer for this, they also have one with a hand pump.

Amazon.com

 

[LTD.330]

How many pumps does it take to fill one of those mini tanks with a glorified bicycle pump? I know that a full size scuba tank is around 3000-4000 PSI.

 

[Flyer5]

• 【Three Inflate Ways】The scuba tank's inflation interface is 8mm, and the work pressure is 3000Psi/200Bar/20Mpa. There are three ways to refill the scuba tank. First is by using a refill adapter, contacting the big bottle to guide vials. (Normally in the diving store). You can also use an electric compressor, a 0.5L bottle needs 10 minutes to refill completely. The third way is by using a handpump, which is difficult to refill the bottle completely. We recommend using it as a backup device.

 

[Flyer5]

For time just under the boat something like this might be better.


https://www.ebay.com/itm/155771895829?itmmeta=01HQ9KFDSR6P51Q27RMJQZ9CA9&hash=item2444ba8015:g:YJ8AAOSw7iNkaxAY&itmprp=enc:AQAIAAAA8D5ansCjP+GJBs0cZWoFjxKgnyftAh1JAuvs5moIgfxKiw3TL1j20CpNEHcOq2GnbbBdYaEeZeY3QIEAmzQrnHI3r/GV7+cueTtv2OXID3LMpLo/s2FYl4BXY0C0nIZ02je65moEm0ETNGKmGT9IiBzf9ofm3j6GJD7moQPpDHO4k+dBD4D+Ck65m6hxfLkDjDC3Tq3t8qiOxubOjN5YGfH1SP9vCB47zRJ2GjWZFZOy7w7GHgO96B1qAdp0qODrgRWNfEDAJQ39/Ix5uKHwgigN3ClTewIF3Y2QqJmnMD2/X/4BEqYZR+RbMlfmQlmL4g==|tkp:BFBMht29s7pj

Or this.

Underwater Scuba Diving Snorkel Equipment Trap Mobile Ventilator 3.5-5H Diving | eBay

The system is the perfect way for snorkelers to venture beyond the surface. This is a very compact Surface-Suppied-Air dive system that supports one diver to 39.4ft/12m. 【����‍️Make Diving Easier】 Traditional oxygen cylinders need to be pumped up.

www.ebay.com

 

[Mark.60]

I have been diving for years. I keep a 21 cubic foot tank with regulator on board. Be careful doesn’t take much to get hurt underwater. Those small devices don’t have a pressure gauge so when you run out of air your in trouble.

 

[dtfeld]

For time just under the boat something like this might be better.


https://www.ebay.com/itm/155771895829?itmmeta=01HQ9KFDSR6P51Q27RMJQZ9CA9&hash=item2444ba8015:g:YJ8AAOSw7iNkaxAY&itmprp=enc:AQAIAAAA8D5ansCjP+GJBs0cZWoFjxKgnyftAh1JAuvs5moIgfxKiw3TL1j20CpNEHcOq2GnbbBdYaEeZeY3QIEAmzQrnHI3r/GV7+cueTtv2OXID3LMpLo/s2FYl4BXY0C0nIZ02je65moEm0ETNGKmGT9IiBzf9ofm3j6GJD7moQPpDHO4k+dBD4D+Ck65m6hxfLkDjDC3Tq3t8qiOxubOjN5YGfH1SP9vCB47zRJ2GjWZFZOy7w7GHgO96B1qAdp0qODrgRWNfEDAJQ39/Ix5uKHwgigN3ClTewIF3Y2QqJmnMD2/X/4BEqYZR+RbMlfmQlmL4g==|tkp:BFBMht29s7pj

Or this.

Underwater Scuba Diving Snorkel Equipment Trap Mobile Ventilator 3.5-5H Diving | eBay

The system is the perfect way for snorkelers to venture beyond the surface. This is a very compact Surface-Suppied-Air dive system that supports one diver to 39.4ft/12m. 【����‍️Make Diving Easier】 Traditional oxygen cylinders need to be pumped up.

www.ebay.com

I read some reviews on the inexpensive Amazon SMACO. Local dive shops wouldn't fill due to suspect DOT certification. The Spare Aire that Tom @ttmott has seems to be more official and people have luck with that unit.

I'm already suspect of any of these on Amazon, I think the Ebay versions are a bridge too far. To many unknown materials to be used in breathing apparatus.

 

[dtfeld]

I have been diving for years. I keep a 21 cubic foot tank with regulator on board. Be careful doesn’t take much to get hurt underwater. Those small devices don’t have a pressure gauge so when you run out of air your in trouble.

On a 60' you have more room. I was thinking for smaller vessels, this might be a great safety system.

 

[Mark.60]

You also have to be a certified diver to fill any tank in a dive shop. A 21 cubic foot tank is about 4 inches in diameter and 18 inches tall

 

[dtfeld]

How many pumps does it take to fill one of those mini tanks with a glorified bicycle pump? I know that a full size scuba tank is around 3000-4000 PSI.

I see one add that the hand pump is a "backup" and takes approx 30 minutes of pumping.

Better be a damn serious emergency for that kind of effort!

 

[ocgrant]

This is the kit I keep on the boat. Gives me 30 mins under the boat no problem. I keep the tank full and it easily fills from another tank. Stores easily and ready to go in a few mins. I have a spare air also for deep dives but would not use that personally for what I would need if I need to get under the boat. Now the battery powered hookas are interesting

 

[Ericinmich]

This looks like the perfect answer for this, they also have one with a hand pump.

View attachment 159460

Amazon.com

I'd stay away from the full face stuff IMO...

I'm a diver, a spair air bottle, sling bottle or a hooka thing would be my preference.

 

[Brent Nutting]

I have a small bottle I use. It's called a Spare Air. It's good for probably five or six minutes depending upon depth. Never had to use it however. It is filled from a standard scuba tank. The mouth piece is on the tank so it isn't very utilitarian as you have to keep a hand on it.
I've never seen the systems filled with a hand pump - interesting....

I too have the Spare Air tank. Backup for diving if my main tanks run out due to a failure. This is a backup safety piece of equipment which should provide enough air to surface in an emergency situation. Mine is old and I should probably have it scoped to ensure the condition is still good.

 

[ttmott]

I too have the Spare Air tank. Backup for diving if my main tanks run out due to a failure. This is a backup safety piece of equipment which should provide enough air to surface in an emergency situation. Mine is old and I should probably have it scoped to ensure the condition is still good.

You should have it rebuilt. The valve isn't the best. I was diving in Palau and it started to leak down and I couldn't get it fixed. Had to borrow an octopus to get back to diving. These days for the deeper diving (90+ feet) I have both the Spare Air as well as a ScubaPro inflator/secondary air. The idea is if my dive buddy has an issue I can hand over the Spare Air and I'm not dependent on his decom stops. The Spare Air is a safety device that isn't designed for routine use. BTW I never lay it up full of air. And, it is good practice to get it VIP'd at least every couple of years. Just make sure they don't stamp it.

 

[Brent Nutting]

You should have it rebuilt. The valve isn't the best. I was diving in Palau and it started to leak down and I couldn't get it fixed. Had to borrow an octopus to get back to diving. These days for the deeper diving (90+ feet) I have both the Spare Air as well as a ScubaPro inflator/secondary air. The idea is if my dive buddy has an issue I can hand over the Spare Air and I'm not dependent on his decom stops. The Spare Air is a safety device that isn't designed for routine use. BTW I never lay it up full of air. And, it is good practice to get it VIP'd at least every couple of years. Just make sure they don't stamp it.

Thanks TTMOT, appreciate it. I lost my dive buddy a couple of years ago, so I haven't been down in a little while but I have a good couple of candidates to partner up with and get back in the water.

 

[Skybolt]

I'd stay away from the full face stuff IMO...

I'm a diver, a spair air bottle, sling bottle or a hooka thing would be my preference.

Been diving since I was a kid, haven't in many years due not being able to clear past 35'. But I actually like the full face for surface stuff. I agree on a full dive outfit. But for fixing/cutting rope off of a prop this might not be bad.

 

[blaster]

Been diving since I was a kid, haven't in many years due not being able to clear past 35'. But I actually like the full face for surface stuff. I agree on a full dive outfit. But for fixing/cutting rope off of a prop this might not be bad.

I think the link you posted looks like a good solution for someone who just wants to do a quick inspection. A pony bottle is not really useful for anything more that extra air for an emergency ascent. Having a a surface tethered air supply is the safest way to go about working under a boat in my opinion. Having a tether adds an element of safety against disorientation or entrapment. Having a buddy on the boat to monitor your air supply and watch for a signal by tugging on the tether adds an element of safety as well.

 

[Skybolt]

I think the link you posted looks like a good solution for someone who just wants to do a quick inspection. A pony bottle is not really useful for anything more that extra air for an emergency ascent. Having a a surface tethered air supply is the safest way to go about working under a boat in my opinion. Having a tether adds an element of safety against disorientation or entrapment. Having a buddy on the boat to monitor your air supply and watch for a signal by tugging on the tether adds an element of safety as well.

That's what this thread is about right? Going under the boat in an emergency and not for actual diving a reef etc.

I kind of agree on the tether thing, but have gone under so many times, I am at the point of getting a diver to do it. The last time I went under, the boat heaved so bad my arm had trouble forcing me down out of the way, I wasn't ready for the heave. That was the end on me doing that. Getting hit in the head by the hull is almost certain death.

The issue is unless your arm is fully extended and you have enough depth so your not touching the bottom, then your ok. That wasn't that situation and I just wasn't ready for the heave. Some ya hoo was throwing a wake where he shouldn't have been and took me by surprise.