Slow & steady little compressor- curious and/or seeking

[seascaper]

Sorry Iain,
Power supply's not limited per se, it's just costly. We get 110/220 at 50Hz from the mains. Outages certainly happen, too, and for larger/longer fill sessions we could/would certainly rent bottles and get fills at the Park/dive shop.

Our nursery depths are less-than 20', usually less than 10' when they're buoyed mid-water, so a 3K 80' lasts 90-120min without too much trouble. 3 bottles with brekki & lunch breaks gives a thoroughly debilitating 7hr wet-day, x 3 bodies makes for 9 bottles. Not much call for rebreather, though my druthers might err towards a hookah.

Most of our out-planting is at a similar depth, but the moving-about needs tanks (rather than boat-mount hookah). Snorkel is by far the most efficient <1.5m, so we're getting breath-hold training from the ex-pro up the coast in the springtime http://www.apneablue.com/?page_id=2

Having said all of that, in 18-months we start out-planting 4500 staghorns at 10-14m: computers with each tech and an O2 drop-tank 5m. We'll likely pear back to 2~3 wet-work days per week (at depth) with only 2x tanks/day and/or get a 4th tech, depending on how we go incl. how the methods adapt over the next 1.5years. Patents pending...

Andrew

 

[tbone1004]

@seascaper for those depths and times, why not look at a tow-behind hookah? unless currents are really bad, they aren't that difficult to tow around and from those depths, just carry an al40 for bailout and you'll be good to go

 

[iain/hsm]

@seascaper for those depths and times, why not look at a tow-behind hookah? unless currents are really bad, they aren't that difficult to tow around and from those depths, just carry an al40 for bailout and you'll be good to go

At first glance because of the TTUP and shallow depth I too would certainly consider the Hookah idea.
Just not for long. Because when you look deeper into it for three people running 7 hours each day on a small Honda petrol (gas) engine will cost you more in fuel than the HP air compressor.

Assuming a good quality oil free LP pump such as the Tomas single stage compressor block or Gast your looking at air flows of 12 cfm at the surface and around 10 cfm at 40-50 ft depth good for your three divers.

Then you need to drive the thing and 4BHP Honda engine is what your looking at. The Honda GTX 140 runs about 3 hours on a tank of petrol. So your already at least three fuel tank fills a day and good luck after a week running with all the rust that starts to form.

Besides who (as an ex commercial diver) is going to sign off three divers sharing the same single compressor air supply source running live even remotly near to a petrol engine with no additional safety surface support.

Dead in the water would be my take on the idea, both for the idea and by implication.

And I wouldn’t take too kindly to breath holding as an idea either or as an option.

I should add in my diving school training we were not allowed to hold our breath for more than 4 minutes as they determined it caused brain damage, They had a point.

 

[tbone1004]

@iain/hsm I was thinking the electric hookah from Brownies
Each set of batteries is good for ~60min and can handle three divers to 15m.
$5700 for a 3x diver system including bailout bottles, add another $800 for 2x spare sets of batteries and chargers which are easy to swap and you're good to go.
Cost there is electricity for recharging the batteries and the fact that when you are at 10ft, you are limited to about 75min dive time vs. 2 hours

 

[iain/hsm]

in 18-months we start out-planting 4500 staghorns at 10-14m: computers with each tech and an O2 drop-tank 5m.
Andrew

Crikey Andrew now you tell us!!! 4500 coral planting in what time? and for how long this is serious commercial aquaculture sounds like your going to need a whole bunch of farmers at work rather than divers to get this off the ground. But this is a tad more than a divers forum can handle, if this is a commercial application and your divers are paid to do this work I'm not sure we can be as informal in our varid suggestions and not consider a whole raft of pitfalls here.

What the heck are you making here? the Great Barrier reef?

All bets are off I'm going with that this will end up as a full surface supplied spread with a chamber on deck Iain

 

[iain/hsm]

@iain/hsm I was thinking the electric hookah from Brownies
Each set of batteries is good for ~60min and can handle three divers to 15m.
$5700 for a 3x diver system including bailout bottles, add another $800 for 2x spare sets of batteries and chargers which are easy to swap and you're good to go.
Cost there is electricity for recharging the batteries and the fact that when you are at 10ft, you are limited to about 75min dive time vs. 2 hours

Shoot. Stop thinking scuba rinky dink. This is amatuer pool/hull cleaning kit. The stuff you use on your yacht once a week in the summer for your holiday spills and thrills.

This guy is making his own coral atol by the sounds of it. At the rate he intends planting you will be able to see the thing from space and your going to do this battery powered?
Give me strength.

This will make China and the Spratly Islands look like using a bag of sand for a mooring post. We are way past Kansas now my friend. LOL

 

[TrimixToo]

Thanks Ian,
I've got ~20bottles in the current collection, old and brand-spankin' new.

We use 6~12 bottles/day in set-up & monitoring days and <6/week through grow-out phases. Perfect-world there'd be something at ~1cfm on some manner of quiet & high-efficiency motor (island= electricity is costly). It sounds like that last 1000PSI is excessive work/duration, as I'd thought it might be.

Larger machine is more noise, thus timing issues with work, sea, sleep, neighbours etc. and/or tank-changes at X-minute intervals. I'd prefer to go to bed and wake up to a rack of ready-to-go bottles but fully appreciate the risks with "set & forget".

(Amongst) my problem(s) is the down-time of compressors at dive-shops & Marine Park office (mechanical & professional), plus time, travel & traffic in drop-collect. Autonomy is becoming my general ethos with efficiency getting to be getting to more important than actual cost, though I'm still a wee start-up so up-front cost remains extremely relevant.

Steel banks only go to 2500PSI, no? Thus still need to let machine run at elevated PSI, then start machine to top-up before work-day or spring for the Haskel? I'm trying to not make yet another investment (in gear & importation, space, time, risks etc) if there's an option, though I appreciate that there's not much for options unless I take BRT's kind offer (thanks, but it'd strain the budget for now).

Thanks again,

Andrew

If electricity is that expensive, you might consider a gas-powered compressor. (I have an Onan engine that will run a K14, free to a good home but it's sort of a long distance for you to come pick it up.) Just a thought.