Spare Air, Emergency air cylinder.

[capnsensible]

Anyone used one? Looking for feedback.

Lots of places use the 'lazy line' way of mooring boats, inevitably resulting in the odd tangle round the prop.

Im wondering if this device might be useful to give one time to sort that out, or actually any prop/rope love affair!

Recently having someone on board who, by sheer bad luck, introduced a line to a prop on my boat, Im looking for ways ahead. My very nice next door neighbour lent me a wetsuit (kindness....it meant I had to go in!!) but staying under is not easy and I hate swallowing gallons of seawater.

Appreciate any comments, ta.

 

[capnsensible]

Link here:

http://www.divepursuits.com/product...rce=gbase&utm_medium=gbase&utm_campaign=gbase

 

[Monique]

I was a diving instructor and am conservative on these matters.

IMO, repeat IMO, get a real course and buy real scuba gear. What is your life worth?

 

[capnsensible]

I was a diving instructor and am conservative on these matters.

IMO, repeat IMO, get a real course and buy real scuba gear. What is your life worth?

Thanks, but yeah, completed Open Water Diver course and have done quite a bit in places (various).

All I am looking for is a few safe minutes under the prop, say 1 metre. With those constraints, is it good?

 

[Skylark]

Just don't see the point of one, frankly. Not enough air to be of any use and enough air to put you in a position of risk, IMHO.

I'm guessing their water content to be about 0.5l. Working pressure, again a guess, 232 bar, that's about 200 bar "cold" or 100 litres to consume. Standard assumed air consumtion at the surface is a breathing rate of 25 litre per minute. Empty tank in 4 minutes at the surface. Now dive, albeit a couple of metres(2m = 20% more consumption), now add a bit of work, either scrubbing the hull or wrestling a snake around the prop.

If you have a basic dive qualification, you'd be better to buy second hand gear and keep it on the boat, again, IMHO.

I'm an active BSAC diver / instructor with >1000 dives in my logbook.

 

[Seajet]

Captain Plummet

I am NOT a trained or qualified diver, but have often wondered about this clearing prop's issue.

So I have opted for the intelligent / cowardly solution, an engine in a well...

A good chum who was very experienced in snorkelling, with a little Scuba experience was on his parents' yacht when they picked up what turned out to be a plastic tarpualin around the prop in mid-Channel, and as it was calm spent the next 2 days drifting around, and I've seen their photo of a nuclear submarines' periscopes & masts going close by while they were diasbled ! I think I might have been on the VHF to arrange a tow before then.

My chum had tried going over the side with a bread-knife to clear the prop', but it was so cold in June that he couldn't do it; when the boat was finally lifted, it turned out the plastic sheeting had 'welded' itself around the shaft, and took a good deal of effort to remove even then.

There was a 'shallow water breathing apparatus' - SWEBA - designed for just this purpose, but it didn't seem to catch on, and I imagine there would be serious issues re. training & health & safety nowadays; I think one normally has to use a lead weight belt when diving, which could spell bad news for the untrained type having a quick try !

 

[prv]

I think one normally has to use a lead weight belt when diving, which could spell bad news for the untrained type having a quick try !

Not especially; the lead is there to counteract the buoyancy in a neoprene suit, taking you back to about the same as swimming in your trunks. You need weights for snorkelling in a wetsuit as well (unless you spend 100% of the time floating on the surface) and that doesn't involve any training.

Just don't pick up a diver's belt with enough lead to sink a bulky suit and all his gear and strap it on over your 3mm shorty. You need to match the weight to the suit.

Pete

 

[Seajet]

Pete,

understood, but is there any simple way of clearing a fouled prop with some sort of unqualified, 'mild scuba' type gear ?

I'm used to dinghy sailing in wet & dry suits, but both are a bit bouyant - especially dry suits.

I do carry a decent mask & snorkel in case of getting tangled up ( despite having the engine in a well ) and have serrated knives stowed at both ends of the boat - learned that one the hard way on a chum's boat with a doubled up warp incorporating a knot in the middle ! - but apart from things like SWEBA or proper Scuba kit requiring training & qualifications, I reckon El Yotto is a bit stuffed ?!

 

[capnsensible]

Thats it seajet, exactly my question. I really appreciate the pro advice, hence my asking.

As I mentioned, having been under, free swimming on not just that occassion, I really cannot hold my breath for too long and found at the last attempt, I came close to being in a bit of stress, swallowed a bit of water and felt lucky to get away with it. Just a few minutes air at only 1m or 2psi depth would have been enough, I reckon.

But I will take the advice of them what knows.

Trouble is with full kit, which I have taken on yachts, it uses a lot of room and is easy to knock chunks out of gelcoat......clearly, though not as important as safety.

The makers reckon the 85 litre bottle gives 57 surface breaths, no idea what that will do 1 to 2 meters.

Lucky news though, I just bought a 2 piece 5.5 mm wet suit for 20 quid!!! Good nick too.

CS

 

[prv]

understood, but is there any simple way of clearing a fouled prop with some sort of unqualified, 'mild scuba' type gear ?

Not really. Normal diving kit itself is about as simple as you can get and still work, so the only way to "simplify" it for sailing use is smaller cylinders and/or optimised packaging (like the one reviewed in PBO a while back that looks like a small rucksack). The actual mechanism remains the same.

Have to say, though, diving to propeller depth is not rocket science. Plenty of "try a dive" type outfits are happy to strap a cylinder to complete beginners and let them roam around a swimming pool, and they don't all emerge with their lungs hanging out of their noses.

If I was buying kit for this purpose I'd probably look for one of the smaller "pony" bottles that technical divers use for decompression mixes etc - bigger than a "Spare Air" but not as big as the 10litre that's the smallest standard tank. Then a regulator with a "button" pressure gauge mounted directly to it and a single second-stage as the only hose.

Pete

 

[Seajet]

I really cannot hold my breath for too long and found at the last attempt, I came close to being in a bit of stress, swallowed a bit of water and felt lucky to get away with it. Just a few minutes air at only 1m or 2psi depth would have been enough, I reckon.

Capn,

couldn't agree more !

When about 19, and much fitter than I am now, I tried snorkelling off the rocks at St Malo...

The water was a bit cold, and I was the only one without a wetsuit. I didn't knowingly feel anxious or anything, but did find I was suffering a sort of vertigo, the feeling of being suspended in the clear water with the 'cliffs' sloping away underneath; I decided to give up & get ashore, but as I'd been what I now know as hyper-ventilating I fell straight over on the rocks, slightly nadgering myself on the barnacles; I'm sure the locals watching thought I was drunk !

I suspect if I tried that - or diving on a fouled propellor - now aged 50, it might be a one-way trip...

 

[prv]

The makers reckon the 85 litre bottle gives 57 surface breaths, no idea what that will do 1 to 2 meters.

At 10 metres the pressure is doubled (100% more) so it follows that for every metre you are adding an extra 10% of surface pressure. This translates directly into 10% more air used per breath (because it's packed in tighter but your lungs still take in the same volume of it).

So your makers reckon you use 1.5 litres per breath (85/57), or an equivalent of 1.8 "litres" at 2 metres depth. That works out to 47 of those breaths.

Not sure how accurate their reckoning is though, especially if you're working hard wrestling with a length of old trawl warp.

Pete

 

[Colvic Watson]

I thought about buying one and asked a mate who's a scuba instructor. He said they were known as death tanks - they carry such a small amount if air when the effects of pressure are considered that they give you just enough air to get into trouble but not nearly enough to get out of trouble. His recommendation was a simple scuba course and a proper half size tank.

 

[prv]

I suspect if I tried that - or diving on a fouled propellor - now aged 50, it might be a one-way trip...

I used to snorkel pretty well as an older teenager; once rescued a lady's watch from the bottom in twelve metres of water after she dropped it over the side while rafted next to us. No chance I could do that now.

Pete

 

[Seajet]

Pete,

funny you should mention that.

The snorkelling, diving chum I mentioned once recovered a Rolex for someone at Lymington town quay, we teenagers expected to get a good meal out of it, then said chum was given the princely sum of £2.00; we considered grabbing the watch and throwing it back in !

The worst 'diving' experience I ever had was going underneath my Dad's Centaur to clear weed off the prop' as she settled on a falling tide at East Cowes Marina; I tried to block my mind to the deposits on the mud as I rummaged around - I don't think I'll be repeating that any time soon !

Andy

 

[KellysEye]

We have dive gear on board but we didn't use it to clear our prop when we got a rope round it. Mask, snorkel and fins and a serrated knife are sufficient. A wet suit is buoyant so you would have real difficulty staying down. Buy some (or borrow) some lead weights 2, 4 and 6 pounds which should give you the options to achieve neutral buoyancy according to the thickness of the suit. To check your neutral buoyancy put on the wet suit, mask etc and say 6 pounds of lead on a belt. Stand up in the water, feet off the bottom and the water should come up to the middle of your mask. If it goes higher too much weight, lower to little.

 

[neale]

http://www.microdive.com/ is what you want.

The kit is compact and easily stowed on a boat and it comes with its own training course, which is not as intensive as a PADI as it only deals with depths up to 9m.

This means it is quicker and easier to obtain than a PADI, but provides all the knowledge you need to dive within the parameters.

 

[Seajet]

Kellys Eye,

thanks but it seems a touch dodgy suggesting untrained, unqualified people use weights, lest they spot the Titanic while passing by the hard way ?!

 

[prv]

thanks but it seems a touch dodgy suggesting untrained, unqualified people use weights, lest they spot the Titanic while passing by the hard way ?!

That was the point of my post, although not really what you addressed in your reply to it.

Putting on a couple of kilos to counteract a thin wetsuit is not going to send you plummeting to the depths. It should leave you exactly as you were before you put the suit on.

In any case, weightbelts all have quick-release buckles.

Pete

 

[RobbieW]

Hookahs

Theres also a variety of hookah systems, of which this is one. One big advantage seems to me to be that it doesnt need a refill once you've used the 4/5/10 litres other small systems provide. I've no idea what the divers think of such devices - I'm sure we'll find out