Nemo by Blu3 battery-powered tankless dive ‘hookah’ systems

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Introduction

You might spot us around using a Nemo Blu3 system (now superseded by the Nomad Mini). It’s a battery-powered dive system with a 3m hose and regulator. It’s like a halfway between snorkelling and diving. It enables the user to remain submerged for periods of an hour or more and I love using it, particularly for taking macro photos!

Who might use a Nemo Blu3?

Divers will find this easy enough to use, though it takes a bit of fine-tuning in terms of buoyancy. People who haven’t dived before will be on a learning curve in terms of buoyancy. This is perhaps the hardest thing of all to master and can take some divers months to perfect.

Anyone who buys or uses one of these will need to complete the Digital Online Training, Disclaimer and Medical Fitness Form as there are some serious safety matters to consider – I’m not going to go into these as I’m not qualified to explain. Needless to say, lung over-expansion and drowning are both possibilities! If you buy one of these it’s your responsibility. I am not recommending this to anyone who doesn’t know how to use it.

Note, the unit I use is limited to 3m (realistically ~2.8m, as you need a bit of give in the hose). This is ample for poking around the base of coastal reefs in Port Phillip Bay. For reasons I explain below, any deeper than this may be a bit tricky. Buoyancy is going to be one of the hardest things to learn if you’re not used to it.

The units are CE Marked in accordance with EN 1012-1:2010 of the European Union, which deals with all significant hazards, hazardous situations and events relevant to the design, installation, operation, maintenance, dismantling and disposal of compressors and compressor units, when they are used as intended and under conditions of misuse which are reasonably foreseeable by the manufacturer. This of course means you should never use the unit without undertaking all the mandatory training.

How long does the battery last?

On my first proper dive I did 65 minutes* and it was still going strong. The new Nomad mini has a battery life of 35-40 minutes.An extension pack can be bought to double the dive duration. Given I’m mostly in about 2m of water, it’s nothing to surface and snorkel intermittently. It’s no different to constantly duck-diving but actually puts less pressure on my ears.

What does it feel like to breathe?

Breathing in isn’t as smooth as a regulator. Although the Nemo by Blu3 is quite silent above the surface, there is a shudder through the hose which makes it a bit noisy. Not noisier than diving, just different. I also find that in very shallow water there is a little bit of positive pressure through the purge valve. This can be a bit annoying as the air noisily ‘pops’ out sometimes.

The air flow is quite free but it is also easy to breathe a mouthful of water at the start. I find it’s really important to purge the regulator before starting to breath. Normally when you dive the regulator is in your mouth before you enter the water. Whereas with this device, you’re more likely to have it submerged before taking a breath. Breathing in seawater can cause an immediate drowning response. I find it best to breath above water once before diving to alleviate that risk.

What does the Nemo by Blu3 feel like to tow around?

This was the biggest surprise for me. Once I had the ‘backpack’ on, I couldn’t really feel it at all. As I snorkelled out I’d turn around to check whether it was still there. At depth it would glide very freely above me. It will only occasionally ‘tug’ at my back when I am about 2.8m or deeper. It is extremely comfortable to use and like diving, there are moments where you forget it’s there.

What about running out of air?

Unlike a dive tank it doesn’t run out suddenly. The Nemo by Blu3 battery declines after a while and you’ll find it increasingly harder to breathe. That’s plenty of time to surface. But it helps to have a dive plan.

Making a dive plan

For use in nearshore areas I stick to places I know. I’ll snorkel a location first and familiarise myself with the terrain from above. One of the risks is that I’m effectively diving on my own, which is a calculated risk I’m prepared to take. But I am very glad to have a dive watch and compass with me. The chances are you’re not going to drift out to sea at 3m but ideally you’d ‘turn the dive’ after 30 minutes and start heading back inshore. It’s easy to get lost so knowing what direction the beach is, at least helps you to navigate back in roughly the right direction. I keep my snorkel on my mask (unlike when I’m diving) so I can resume breathing at the surface. Then the regulator just comfortably hangs off my neck.

Risk of boat strike

The unit comes with its own yellow fluorescent float and dive flags. In theory vessels are supposed to remain 50m from any such flag. Should a boat run over the unit I’d hear it coming, remain low and surface once it’s passed. It’s probably less risky than snorkelling. But to be safe, I try to remain with my head mostly below surrounding reef level anyway. There is little to no chance of being struck by a boat that way.

Buoyancy Control for the Nemo by Blu3

Using a wetsuit

This is the hard part and where some dive training is useful. Often gear and techniques are developed for warm water where there’s no necessity to use a thick wetsuit. Wetsuits make you very buoyant which necessitates the use of weights.

But there is no simple qualification for snorkelling that helps you learn how much weight to use. It comes down to trial and error. But snorkelling while over-weighted is dangerous as you simply sink and there have been tragedies occur where people panic from not being able to stay afloat.

The reality is that there is no guidance on how to achieve correct buoyancy for using a system like Nemo by Blu3. What is certain is that you will most likely need to swim out to your dive spot before using it. This means you don’t want to be carrying more weight than you need to comfortably float at the surface.

Lung control for buoyancy

In diving you have a buoyancy control vest, which means you can fill it with air to compensate for being over-weighted. But with the Blu3, you need to regulate your buoyancy between 1-3m by just using your lungs. A diver knows how to breathe at the top or bottom of their lungs to get this just right.

If you are snorkelling, when you duck dive, air compresses in your lungs and you start to sink. But if you take a breath from the Nemo by Blu3 regulator after submerged, you will reinflate your lungs and start floating up. If you’re inexperienced, this might make you anxious and your breathing rate will increase, making it even harder to stay down. Conversely, if you’re overweighted, you may sink like a stone making it hard to get off the bottom.

I already know exactly how much weight I need to be neutrally buoyant wearing my 5mm semi-dry suit, with a lung full of air, so I ‘float’ about 30cm above the sediment at 3m after duck-diving down. So, I am easily able to breathe from either the top or bottom of my lungs to control buoyancy and remain fairly static in the water column.

Nevertheless, when I first used it, I still found it a little tough to stay down but that improved throughout my swim. By the time I finished I was in only 1.3m and being completely relaxed, could stay submerged easily

We love the Nemo by Blu3 as an additional tool in the snorkelling kit. It’s good to tow along anyway to have a good snorkelling float and the option of staying underwater from time to time.

The 3m limit is about right. I suspect any deeper and it may be hard to remain submerged in the shallows, or you might be tempted to overweight and end up crawling along the seafloor. Since you’re mostly going to use this to swim from a beach, you really want to be able to stay ‘hovering’ in 1-3m. For macro photography it’s really useful, as you can get out of the surge a little, as well as stay longer to frame shots. For fossil-hunting it’s also really cool. It’s easier to find smaller things that would go unnoticed otherwise.

If you’re really confident in the water and have the skill or patience to learn how to control your buoyancy in the shallows, this offers a great experience. Being so lightweight, you can just walk it down to the beach! Cost-wise they are quite expensive but about the same as you’d invest in BCD, regulator, tanks and numerous air fills.