Mini scuba diving: filling the tank

[MPtich]

I am interested in exploring mini scuba diving while snorkelling. My main concern is about filling the mini tank (for example S300 bottle). Would snorkelling / diving operators allow me to use their compressor on board ? Would they charge me for filling a 0.5 liter bottle as for a full diving tank ?

 

[FF / EMT]

The dive boats I’ve been on don’t have compressors on board.
Also, if I was a DM or ran a boat, I probably wouldn’t let you bring that little doo hickey on a charter.
I would try get you into a try scuba course and eventually an OW course.

 

[MPtich]

The dive boats I’ve been on don’t have compressors on board.
Also, if I was a DM or ran a boat, I probably wouldn’t let you bring that little doo hickey on a charter.
I would try get you into a try scuba course and eventually an OW course.

So how do mini divers organize their activities ? Do they travel with their own compressors (at least 6-7 kg) ?

 

[Thunder Struck]

So how do mini divers organize their activities ? Do they travel with their own compressors (at least 6-7 kg) ?

Never heard of "mini" diving. Looking at the SMACO page, looks like made-up marketing term for their version of a Spare-Air. If anything those are sold as an emergency air source to make an ascent should they run out of air at depth. They are designed to be filled from a filled scuba tank. Mostly because shops won't fill them as most owners don't get those bottles annually inspected, let alone hydro'ed every 5 years.

I'm just going to rip the bandage off here: Those SMACO mini-diver bottles are a marketing gimmick. But one that can easily cause you a serious or deadly injury if you don't understand the hazards of breathing compressed air at even shallow depths.

If you are going to snorkel, snorkel. If you are going to dive, dive. You would be better off learning how to do a proper breath hold and spend 2-3 minutes under water without that little suicide bottle.

 

[lowwall]

I'd be extremely surprised if any dive operator will fill your tank or let you dive on their boats with any sort of compressed air tank unless you are scuba certified.

And for good reason. Well, their real reason would be that it would violate their liability insurance coverage. But it's also good sense. Scuba isn't that complicated, but you absolutely need some knowledge and practice to keep from injuring or killing yourself while breathing compressed gasses at depth. Take an Open Water course if you want to breathe underwater. Or take a basic freediving course if you want to improve your snorkeling skills.

 

[FF / EMT]

So how do mini divers organize their activities ? Do they travel with their own compressors (at least 6-7 kg) ?

Never seen a “mini diver”
Most divers travel with a first/ second stage, some sort of alertnate, an spg and a timing device or computer and a BC/ mask snorkel fins.

Since you probably only have a mask and fins, you’ll need to rent the rest of the gear.

Do the “try scuba” course, they’re often free or rather low priced. And if you enjoy it, consider certification.

Sell the s300 thing, you’ll be safer, and find that more places will be accepting of an actual scuba cert

 

[Thunder Struck]

Looking furher at that SMACO web page (SMACO S300 0.5L Plus Scuba Diving Air Tank) it's a blob of marketing BS. They are claiming "5-8 minutes" (although further down the same page it states 6-10 minutes) of time. I'm going to assume you are not familiar with diving and gas consumption, or for the benefit of anyone else who stumbles across this thread in the future via a search engine.

Gas is consumed at a rate referred to as the Surface Air Consumption (SAC) rate. It's how much air you consume, On a basic dive where I'm easily swimming around I'll run around a SAC rate of .5 to .6 CFM, which means I consume 5 to 6/10th's of a cubic foot of air per minute (CFM) at the surface (out of the water). For every 10 meters/33 feet you increase your atmospheric pressure by one, and your SAC rate is multiplied by the total atmospheres of pressure you are working at, or ATAs. So at 33 feet you are at 2 ATA, so in my case I'm consuming 1.2 CFM (.6 CFM x 2 ATA). That bottle (.5 liter @ 200 bar of pressure) holds 3.5 cubic feet of air. So going down all of 33 feet, I'd have less than 3 minutes of air from that S300 bottle. Freedivers can breath hold that and then some. And they don't need to get our of the water and go back to their car to use some some wonky compressor hooked to their car, or doing "600-800" pumps on a high pressure bike pump. Heck, at one pump per second that's 10 minutes, non-stop without a break.

Even going down to just 10 feet (1.3 ATA) it'd last me all of about 4 1/2 minutes. By comparison a standard scuba cylinder will give me over an hour and a half at that depth. Or for the 33 foot depth, over an hour.

Now then, most new divers will run a higher SAC. Also, the more active you are, the more you are breathing, the higher your SAC. My SAC rate will go higher the more active I am. If you are more active, having to swim and keep yourself down, I can easily see a SAC rate of 1 or higher. So, you get a whole minute and 45 seconds at 33 feet, or 2 minutes and 40 seconds at 10 feet. And it only gets worse the higher the SAC rate.

So you manage to get down to 30 feet or so to see the pretty fishes. Only you quickly lose tract of time and go to inhale and only get a partial breath as the tank empties on you. So you quickly race to the surface only to find yourself couging up blood as a result of a lung over-expansion injury since you haven't been properly trained on breathing compressed gas at depth. If you're lucky you've got lifeguards on the beach and an ambulance nearby to get you to the hospital in time. In a semi-remote location, well, there's a reason I refer to those as suicide bottles.

 

[clownfishsydney]

Extremely useless and dangerous and should be banned except for the purpose they were originally invented, escaping helicopter crashes into water.

 

[lowwall]

I've never heard the phrase "mini scuba" either. I'm going to guess this is the result of a TikTok marketing campaign, either directly or through paid "influencers".

 

[Eric802]

Scuba diving is really one of those "do it right or don't do it" things.