The Scuba Doctor doesn't recommend Scorkl devices because we think they're deadly dangerous. Here's why...
The Scorkl is sold as a shallow diving kit that lets you breathe freely under the surface with no bulky scuba equipment to get in the way of your exploring. No scuba certification required. The starter kit, which includes a hand pump, sells for around A$700.
The Scorkl is a 0.5 litre water capacity, 200 bar (2,900 psi) dive cylinder with a regulator and mouthpiece attached directly to the cylinder. It has a pressure gauge mounted on the mouthpiece which can be read without removing the device from your mouth. There is also the larger Scorkl Pro which holds up to 20% more air. If the Scorkl falls out of your mouth, your air supply is gone.
There is a Safety Video for the Scorkl. It has plenty of warnings, many of which seem to come from the recommendations of scuba diving training agencies.
One wonders how many Scorkl users will view the safety video and fully understand the implications. This information is not published on the Scorkl web site as text, not even on their Safety page. No doubt it is repeated in the User Manual, but that is not downloadable from their web site either. At least you can now read the information here. There is a whole world of difference between viewing a safety video, or reading a user manual, and having the technicalities and dangers explained by a qualified scuba instructor.
As one commentator on the Kickstarter page put it, "This is a suicide device, wrapped up as a toy."
Here at The Scuba Doctor, we're not even comfortable with certified scuba divers using a Scorkl, let alone the target market of non-certified divers.
The Scorkl has a maximum depth limit of 6 metres (20 feet). It doesn't come with a depth gauge. How are people going to be able to use it safely?
The founder, David Hallamore, claims the Scorkl is "certified to 6 metres". The safety video says the Scorkl does not meet the requirements of EN250. So one wonders how it is actually certified, and how it could legally be sold in Europe where certification is required.
The recommended safe limit of 6 metres does not rule out the risk of lung over-expansion injuries. A rapid breath-hold ascent from 6 metres would almost guarantee that a user suffers a life-threatening rupture of the lungs.
The recommended maximum ascent rate matches the scuba diving recommendation of not exceeding an ascent rate of 10 metres per minute. But the Scorkl doesn't come with a depth gauge, dive watch, or dive computer. These are the tools used by scuba divers to carefully monitor their ascent rate. There is no way for Scorkl users to accurately judge their depth or ascent rate.
They claim the Scorkl sits weightlessly underneath your chin so you'll barely notice it as you swim. Well we get scuba divers complaining that a lightweight second stage regulator in their mouth produces too much jaw fatigue. A heavyweight Scorkl is not going to be nice and, if the Scorkl falls out of your mouth, your air supply is gone.
Does the Scorkl cylinder meet Australian certification standards? Does the valve/regulator have a burst disk? They don't tell the Scorkl users that scuba cylinders need to be visually inspected and pressure tested at a certified testing station once per year in order to comply with Australian Standards. See Scuba Cylinder Testing. The Scorkl is a scuba cylinder.
A few different options are provided to fill the Scorkl's tank.
The Scorkl is available with what they refer to as a specially designed high-pressure hand pump to fill the Scorkl to 200 bar (3,000 psi). Well it's actually the same type of hand pump that's been on the market for many years to fill small paint ball cylinders. In that application, users don't care much about the quality of the air. The air is not going to be breathed by them.
The quality of the air breathed in by scuba divers is critical. Dive shops spend a lot of money on their compressors, the lubricants used in those compressors, the air filter on the compressor intake, the moisture removal system and the air filtration system to ensure high quality, breathable air. Sources of contamination include hydrocarbons from compressor lubricants, carbon monoxide (CO) from engine exhaust (or overheated compressor oil) and impurities from the surrounding environment such as methane and carbon dioxide (CO2). Dust particles in breathing gas can also be hazardous, potentially impairing respiratory function or damaging diving equipment. Excessive moisture can cause corrosion in scuba cylinders and other dive gear and may cause regulators to freeze due to adiabatic cooling (heat loss subsequent to increased gas volume).
The Scorkl hand pump comes with a replaceable air filter which is claimed to ensure Grade E scuba air quality. No details are given on the Scorkl web site as to how often the air filter should be changed, how you purchase a replacement filter, or what the filter costs.
We've seen no mention about hand pump lubrication. It costs us $500 for a 20 litre drum of oil for use in our dive compressors. What oil is being used with the Scorkl hand pump, and how often should it be lubricated?
A video is provided to show how to use the Scorkl hand pump.
They recommend not to pump for more than 5 minutes at a time. (We doubt many people could.) Then leave the pump to cool for 15 minutes after each 5 minute pumping period. At the start of each cooling period the bleed screw should be opened so heat and moisture can escape. No indication is given as to how many pumping sessions it typically takes to fill the Scorkl to 100 bar.
Recommended fill pressure is 50–100 bar for ease of use and to optimise pump lifespan. What the...! Now consider this in relation to the warning that you shouldn't descend with less than 50 bar, and that you should begin your ascent at 50 bar.
As the Scorkl founder, David Hallamore, says when talking about filling the Scorkl with the hand pump, "You've got to put your back into it a little bit. It takes a while to fill." We suspect only very fit Scorkl users could achieve a 100 bar air fill using the hand pump anyway. We think most will only achieve 50 to 75 bar. They'll find it too difficult and too exhausting to do more.
The manufacturer often refers to how the Scorkl can be easily and quickly filled from a scuba cylinder. But no dive shop would hire a scuba cylinder to someone without a scuba diving certification. So there goes being able to do lots of dives in an outing for most of the targeted uncertified diver market for a Scorkl.
References are made to filling the Scorkl cylinder at a dive shop. However, most dive shops when presented with a Scorkl for an air fill would want to see the user's scuba diving certification before filling it. The dive shop would also want to see that the Scorkl cylinder complies with Australian Standards and is in test before filling it.
The Scorkl founder, David Hallamore, says he is looking into releasing an air compressor for the Scorkl.
We often get asked by scuba divers whether they could use their compressor at home to fill their scuba cylinder. (One wonders who taught them to dive when divers ask questions like this.) That would be a compressor bought for $200 at Bunnings with no air filtration, that's good for about 100 psi (7 bar).
A scuba cylinder needs to be filled from a compressor capable of some 3,500 psi (240 bar), with an excellent moisture removal and air filtration system. A small home scuba compressor setup like this typically costs around $6,000. The Scorkl is a mini-scuba cylinder.
MiniDive have an electric compressor available for $A2,000. A filter change is advised after every full tank filling. Filters are A$45 each. That's an expensive air fill. This is probably the sort of compressor Scorkl are considering.
They claim the Scorkl is good for 68 breaths (when filled to 200 bar), or up to 10 minutes underwater if you're a good, experienced, relaxed diver. (The 20% larger Scorkl Pro for 80 breaths.) They also say a novice that's chewing through air would only be getting two to five minutes out of it. It's not specified at what depth this is. It would have to be very shallow, we suspect not more than 0.5 metre (1.5 feet).
Scorkl give the following table as the total surface breaths available at various fill pressures, assuming 1.5 litres per breath. We've added the litres of air available.
|Fill Pressure (bar)||50||100||150||200|
|Scorkl litres of air||25||50||75||100|
|Scorkl Pro breaths||20||40||60||80|
|Scorkl Pro litres of air||30||60||90||120|
Scuba divers don't talk about air use in terms of breaths. That's because the volume of air used by one breath varies greatly with the depth. At 10 metres it's double, at 20 metres triple, and at 30 metres quadruple. At the maximum depth of 6 metres (20 feet) with a Scorkl, each breath uses 1.6 times more air than that of one breath at the surface. So the Scorkl assumption of 1.5 litres per breath becomes 2.4 litres per breath.
A Scorkl 0.5 litre water capacity cylinder pressurised to 200 bar means you have 75 litres of air to breathe before you hit the 50 bar safety limit. But if you can only fill it to 100 bar using the hand pump, you'll only have 25 litres of air to breathe with the 50 bar safety limit. That's not going to last long, so users of the Scorkl are being encouraged to break these safety recommendations by the marketing hype.
Technical scuba divers actually work out from past dives what their air consumption rates are at various phases of their dives and depths. They convert the information to a surface air consumption rate (SAC). They use these values when working out how much air they need to have, including reserves, while planning a dive. The surface air consumption rate (SAC) for a typical relaxed scuba diver is 20 litres per minute (lpm). It will climb to around 30 lpm if they're actively moving about or working, and can be over 60 lpm in a stressful situation.
The recommended maximum decent rate for a diver is 20 metres per minute, so that's 20 seconds down to 6 metres. The recommended maximum ascent rate for a diver is 10 metres per minute, so that's 40 seconds to come up from 6 metres. Thus a dive to 6 metres has a minimum time of 60 seconds (one minute) for the descent and ascent phases.
A relaxed, experienced scuba diver with a SAC of 20 lpm at 6 metres deep will use 32 litres of air per minute. Let's assume the good, experienced, relaxed Scorkl diver has the same SAC, even though this is highly unlikely. Using a Scorkl filled to 200 bar you have a total of 100 litres of air available. Thus you get to spend two minutes at 6 metres after taking in the ascent and descent requirements. That's not giving you the recommended air reserve of 50 bar used by scuba divers as a safety buffer.
But a Scorkl user won't be as relaxed as a typical scuba diver, as they won't have a BCD to help them maintain neutral buoyancy. Thus a dive to 6 metres, spending two minutes at 6 metres, for a total dive time of three minutes, would see the typical Scorkl user run out of air and arriving back at the surface with an empty Scorkl. This is not recommended as it can damage the device. It can also kill the user.
Now lets look at a novice Scorkl diver who they say will be chewing through air would only be getting two to five minutes out of it. This implies a SAC of at best 40 to 80 litres per minute. If we calculate based on a SAC for this Scorkl diver of 50 litres per minute, this implies that at 6 metres deep the novice Scorkl diver will use 80 litres of air a minute.
But using the Scorkl hand pump, the recommended fill pressure is 50–100 bar for ease of use and to optimise pump lifespan. Assume you've worked hard and filled the Scorkl to 100 bar. You now have 50 litres of air available. That's not even enough for the experienced Scorkl diver to safely do a dive and spend one minute at 6 metres! The newbie Scorkl user is going nowhere. They're probably going to empty it on the surface while doing their safety check. They're not going to get to 6 metres deep and back!
If you properly check the Scorkl as recommended before use by purging it and breathing from it, we doubt a Scorkl filled with the hand pump will have enough air for you to get to 6 metres, let alone stay there and return safely.
They make mention of how the Scorkl is great for boat owners. Examples given are:
They make mention of using the Scorkl for spearfishing. Well for a start, spearfishing on scuba is illegal in most Australian states and the Scorkl is scuba gear. In the spearfishing world, spearfishing on scuba is considered bad form, as it's unfair to the prey, and also the thrill of the hunt is gone.
If you do use a Scorkl for spearfishing, remember that you have a maximum depth of 6 metres. Assuming you breath hold down to 6 metres, and your Scorkl has been filled to 100 bar with the hand pump, you have 50 litres of air maximum, but less after you're done the safety checks. Using a SAC of 30, which is very generous, you have one minute at the bottom, before you're ascending without any air. Less, if you follow the safety instructions. Then it's back to shore to pump up the Scorkl again.
If you ignore the glossy marketing hype targeting unknowing people without scuba diving certifications who thus don't know what vital questions to ask, and take into account the recommended limits of the Scorkl, it's a dud device. People typically won't be able to achieve the results promoted, and even if they have read and understood the user manual, they are at great risk of killing themselves.
The marketing slogan for the Scorkl is, "Breathe underwater with TOTAL freedom." We think it should be, "Kill yourself underwater with total ease!"
For another take on the Scorkl, please view the video Scorkl: BUSTED! on YouTube.
You can also listen to an interview with Scorkl founder David Hallamore at NSP:114 David Hallamore SCORKL — Noob Spearo Podcast.
Much of what we've covered above for the Scorkl also applies to the MiniDive. The marketing hype used for the MiniDive is more conservative. They say it has a max depth of 3 metres for non-divers, but that it works at up to 50 metres. The MiniDive uses a separate second stage regulator on a low pressure hose. The MiniDive has a harness so that you're less likely to loose it. These are thought out changes, but we still consider it deadly dangerous and a suicide device.
Much of what we've covered above for the Scorkl also applies to the Smaco. The marketing hype used for the Smaco is similar to that of the Scorkl. The Smaco uses a separate second stage regulator on a low pressure hose. The Smaco has a SPG to allow you to monitor the air pressure in the cylinder, but you have to remove it from your month to see it. These are thought out changes, but we still consider it deadly dangerous and a suicide device especially in the hands of non-certified divers.
Using devices which allow you to beathe at depth underwater without learning to scuba dive is deadly dangerous. Without the proper training you just don't know how many ways there are tp cause yourself serious injury, or kill yourself. You don't know how to do it safely. If you want to spend more time underwater you need to learn to freedive or scuba dive. There are no cheap shortcuts.
See also, Full Face Snorkel Mask Dangers.