Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 Lots of non-divers want to know if it's possible to extend a snorkel so they can go a little deeper. The answer, as i have read, is no, because the human diaphragm is not strong enough to overcome the increasing water pressure at depth. The draft of my canal boat is 95cm most of which is keel. The chine is about 20cm below the surface and I want to be able to see under this for bottom cleaning. I can do this with a standard snorkel, standing on the bottom of the canal with my head under the water but it means that the top of the snorkel tube is at or near water level which brings with it the probability of ingesting poo water. Not good. So, although I don't want to extend a snorkel to go deeper can you extend it so that the top is a bit further above the poo and still be able to breath ok? Quote Link to post Share on other sites
Crazyhorse 47 Posted January 9, 2019 Share Posted January 9, 2019 Covered this year's ago doing the open water. As I remember it has to do with the amount of air we exhale. I think its about .4 of a litre. The lungs hold about 6 litres so if the snorkel was too long, you would be rebreathing your CO2 which would start to catch up with the oxygen levels in your lungs. The CO2 level is whats dangerous, no so much the oxygen. Sorry, doing this from memory. You would need a way of expelling your Co2...completely. Quote Link to post Share on other sites
khayyam 68 Posted January 9, 2019 Share Posted January 9, 2019 Yes tidal volume approx 500 ml. You'd have to work out the volume of your tube, but of course a skinny little one isn't going to be easy to breathe through either! Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 Yes, I thought a purge valve by the mouthpiece would do it. But in reading further there may be another complication. Apparently 18 inches is about the distance one can suck air down a tube whilst under water due to the surrounding water pressure. Snorkels appear to be designed for the user lying prone and face down in the water. Consequently the snorkellers lungs would be at or close to the water surface. Standing vertically in the water but crouching down with my head under the water (with the aid of a weight belt) means that my lungs would be 18 inches or more under the water thereby making breathing difficult or impossible. I don't know enough about this diving stuff but I think in terms of head under the water hull cleaning, it's back to the drawing board. Quote Link to post Share on other sites
Island Time 1,230 Posted January 9, 2019 Share Posted January 9, 2019 Can't do it safely. Get a hookah - surface supply, with proper regulator Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 Online, check out 'scorkl'. Could be the answer to the boatman's prayers? Quote Link to post Share on other sites
Island Time 1,230 Posted January 9, 2019 Share Posted January 9, 2019 Kim, ones a hookah, ones a hooker. Minor differences in words can get you in a lot of trouble! 2 Quote Link to post Share on other sites
cj! 19 Posted January 9, 2019 Share Posted January 9, 2019 Manual pump refillable bottles like the Scorkl, Spare Air, SMACO, etc. will give you a small lightweight reusable system but with limited duration depending upon your needs. A small 12v electric hookah will allow for a much longer dive duration at a price. Have a look at your space, weight, financial and dive duration requirements. Maybe you can just hire someone to do it for you? Another option for live viewing without getting wet is a GoPro or similar on a pole with a wifi extension cable. Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 A hookah would be great, but I don't need to go that flash or costly. It's a big item to stow on a smallish boat and in Europe I will pay in euros what it costs here in NZD. My boat has keel cooling which is a blessing in that I don't have to continually deal with blocked raw water filters resulting from weedy water, but it does mean that once in a while I have to leap over the side to clean weed (and fishing line) off the water cooling pipes and the prop and rudder. All i need us a system that can give a few brief minutes occasionally under water. So this scorkl looks interesting. Quote Link to post Share on other sites
Island Time 1,230 Posted January 9, 2019 Share Posted January 9, 2019 Same as a "spare air" been around for a while, but never seen one hand pumped before. Quote Link to post Share on other sites
Myjane 40 Posted January 9, 2019 Share Posted January 9, 2019 I clean the bottom off at times and dive with snorkel to the keel , hold breath surface and blow out ,take another breath works ok Quote Link to post Share on other sites
Crazyhorse 47 Posted January 9, 2019 Share Posted January 9, 2019 Same as a "spare air" been around for a while, but never seen one hand pumped before. Ditto considering around 3000psi is required for a dive cylinder. Maybe a completely sealable cabin, a air compressure pump and a hatch you can open in the hull...a moon pool!!? Quote Link to post Share on other sites
cj! 19 Posted January 9, 2019 Share Posted January 9, 2019 The hand pump is a 3 or 4-stage pump that can pump to 3000-4000psi depending on the pump. The MiniDive is another one of these mini scuba kits. Aliexpress and eBay normally have these "mini scuba tank" kits available. Mantus offer a small scuba pack based on a pony bottle but it's not hard to put your own version together, I did this back in the 70's for getting into tight spaces chasing crays or quickly dealing with a stuck anchor. I also built my own hookah as I always ran out of full bottles and getting fills was a problem when you're away on the boat. Quote Link to post Share on other sites
Crazyhorse 47 Posted January 9, 2019 Share Posted January 9, 2019 How does the pump maintain a seal under such high pressure? The reason why I ask is any kind of sealing lubricant getting into your lungs.... Quote Link to post Share on other sites
cj! 19 Posted January 9, 2019 Share Posted January 9, 2019 O-rings. Can use silicone grease but Christo Lube is better imho. Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 I'm attracted to the scorkl because it is hand pumped even though it takes 12 minutes to load it up according to the blurb. Carrying an air cylinder to recharge a spare air type systen would appear in my case to be a bit self defeating. I clean the bottom off at times and dive with snorkel to the keel , hold breath surface and blow out ,take another breath works okI would be happy to do that in NZ, but French canal water? Perhaps not. . Quote Link to post Share on other sites
Black Panther 1,581 Posted January 9, 2019 Share Posted January 9, 2019 I would be suspicious of the claimed 10 min. If you are working it's more likely 2. Quote Link to post Share on other sites
Crazyhorse 47 Posted January 9, 2019 Share Posted January 9, 2019 Yep...Can see the attraction...(laughing gas?) Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 I would be suspicious of the claimed 10 min. If you are working it's more likely 2.I agree with you. Again, from the sales blurb, the 10 minutes is calculated on a tidal volume of 0.5 litres and a resp rate of 6. The developer states that an experienced diver would achieve this but for the average person, 6 minutes. From my ambo days a normal resp rate us 10 - 16 so he is being a bit ambitious.However, aĺl I want to dive for is to clear the occasional dollop of weed that you can always feel when you've picked it up by the wheel vibrating. It is quick to do And not Labour intensive and I can normally hold my breath for around 45 seconds whilst attacking it. Having something that could give me an extra 5 or so mouthfuls of air would be pretty good. And at $200 it isnt too much. Quote Link to post Share on other sites
Guest 000 Posted January 9, 2019 Share Posted January 9, 2019 We will see how it goes. Tomorrow is the wedding anniversary and I have told Joke that I deserve one of those dive thingies for 45 years of loyal service..servitude..? Quote Link to post Share on other sites
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