Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 31-05-2017, 10:03   #1
Registered User
 
KISS's Avatar

Join Date: Sep 2014
Posts: 321
Very Low Pressure SCUBA Tank

I know nothing about SCUBA, so bear with me, this may be a stupid question.

Is there some reason you couldn't use a manual pump to fill a tank to say 10 atmospheres (about the pressure inside a bike tire, so should be doable) and use that for brief, shallow dives (like cleaning the hull)? A standard 0.39 ft3 tank at 10 atmospheres should have enough air for about 10 minutes by my estimation.
__________________

__________________
"If one does not know to which port one is sailing, no wind is favorable."

-- Seneca
KISS is offline   Reply With Quote
Old 31-05-2017, 10:13   #2
Registered User

Join Date: Aug 2010
Posts: 1,236
Re: Very Low Pressure SCUBA Tank

Now, I'm admittedly not a diver. however, a quick google search and a little public school education tells me:

Atmosphere = "atm"
lb per square inch = "psi"

1 atm = 14.6959 psi.

14.6959 x 10 = 140.6959

10 atm = 140.6959 psi.

That is WAY over any bicycle or automobile tire pressure rating.
__________________

Shrew is offline   Reply With Quote
Old 31-05-2017, 10:16   #3
Registered User
 
KISS's Avatar

Join Date: Sep 2014
Posts: 321
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by Shrew View Post
Now, I'm admittedly not a diver. however, a quick google search and a little public school education tells me:

Atmosphere = "atm"
lb per square inch = "psi"

1 atm = 14.6959 psi.

14.6959 x 10 = 140.6959

10 atm = 140.6959 psi.

That is WAY over any bicycle or automobile tire pressure rating.
If you google "bike tire pressure," the first result says that road tires have a typical PSI of 80-130.
__________________
"If one does not know to which port one is sailing, no wind is favorable."

-- Seneca
KISS is offline   Reply With Quote
Old 31-05-2017, 10:28   #4
Registered User
 
Davidhoy's Avatar

Join Date: Jul 2016
Location: Hollywood FL
Boat: Catalina 470
Posts: 921
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by KISS View Post
I know nothing about SCUBA, so bear with me, this may be a stupid question.

Is there some reason you couldn't use a manual pump to fill a tank to say 10 atmospheres (about the pressure inside a bike tire, so should be doable) and use that for brief, shallow dives (like cleaning the hull)? A standard 0.39 ft3 tank at 10 atmospheres should have enough air for about 10 minutes by my estimation.
You'll be lucky to get anywhere close to 145 psi (10 bar) with a bike pump. The problem is that scuba first stage regulators take tank pressure and reduce it to 140 psi intermediate pressure to send to the second stage regulator. Without sufficient pressure in the tank, the first stage won't crack open, and you'll be sucking dry almost right away.

-David
__________________
Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. Mark Twain
Davidhoy is offline   Reply With Quote
Old 31-05-2017, 10:39   #5
Registered User
 
KISS's Avatar

Join Date: Sep 2014
Posts: 321
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by Davidhoy View Post
You'll be lucky to get anywhere close to 145 psi (10 bar) with a bike pump. The problem is that scuba first stage regulators take tank pressure and reduce it to 140 psi intermediate pressure to send to the second stage regulator. Without sufficient pressure in the tank, the first stage won't crack open, and you'll be sucking dry almost right away.

-David
Got it. Is there an electric pump that would be safe to use to fill a tank (still not to normal pressure, but to something well over 140 so as to make the tank usable)? Or would you say a hookah is the better option? ...the huge cost of a proper SCUBA compressor can't be justified for the limited purpose I have in mind.
__________________
"If one does not know to which port one is sailing, no wind is favorable."

-- Seneca
KISS is offline   Reply With Quote
Old 31-05-2017, 10:56   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 2,526
Re: Very Low Pressure SCUBA Tank

I'm a former diver. A Hookah is your cheapest bet. A compressor that produces over 150psi is expensive and expensive to run. When a dive tank gets down to 500psi you should be near the end of your dive. I use a hookah for changing zincs, etc., and it works fine. Fast to setup and use and no trip to get tanks filled.
Don't gather dive equipment and dive without dive school. It's easy to kill yourself, I nearly did as a teen.
Lepke is offline   Reply With Quote
Old 31-05-2017, 11:14   #7
Registered User
 
Davidhoy's Avatar

Join Date: Jul 2016
Location: Hollywood FL
Boat: Catalina 470
Posts: 921
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by KISS View Post
Got it. Is there an electric pump that would be safe to use to fill a tank (still not to normal pressure, but to something well over 140 so as to make the tank usable)? Or would you say a hookah is the better option? ...the huge cost of a proper SCUBA compressor can't be justified for the limited purpose I have in mind.
As someone else has already pointed out, a hookah system is your best bet. Just make sure that the air intake is nowhere near the engine or generator exhaust.
__________________
Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. Mark Twain
Davidhoy is offline   Reply With Quote
Old 31-05-2017, 11:27   #8
Registered User

Join Date: Jun 2012
Location: Port Aransas, Texas
Boat: 2019 Seawind 1160 Lite, Previous 2002 Seawind 1000
Posts: 1,332
Re: Very Low Pressure SCUBA Tank

A couple of the bottom cleaning guys in my marina use simple compressors in the dock, with hose to regulator. My sister who is certified says this is dangerous as they could be breathing in line oil droplets from the compressor. Comments? At least two divers here are using the cheap "pancake" compressors.
sailjumanji is offline   Reply With Quote
Old 31-05-2017, 11:32   #9
cruiser

Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
Re: Very Low Pressure SCUBA Tank

They're probably oilless with an inline filter. You can by a decent 110v model at the home depot for $99.
Kenomac is offline   Reply With Quote
Old 02-06-2017, 09:54   #10
Registered User

Join Date: Aug 2010
Posts: 1,236
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by KISS View Post
If you google "bike tire pressure," the first result says that road tires have a typical PSI of 80-130.
My Mtn bike tires run around 30psi. My dirtbike tires run around 13psi. Maybe some performance road bikes get up to 80-130psi. You'll find most recreational bikes out there are riding around with significantly less.
Shrew is offline   Reply With Quote
Old 02-06-2017, 10:28   #11
Registered User

Join Date: Dec 2015
Posts: 566
Re: Very Low Pressure SCUBA Tank

Quote:
Originally Posted by Shrew View Post
My Mtn bike tires run around 30psi. My dirtbike tires run around 13psi. Maybe some performance road bikes get up to 80-130psi. You'll find most recreational bikes out there are riding around with significantly less.
I always pumped my touring bike to around 110.

Higher pressure means less rolling resistance.
__________________

Jdege is offline   Reply With Quote
Reply

Tags
Cuba, scuba

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mann 900 v8, Low pressure coolant tank and loosing water NicholasHill Engines and Propulsion Systems 3 30-06-2016 21:50
Low Oil Pressure at Low Revs Streetcar Engines and Propulsion Systems 6 16-03-2012 11:07
One Very, Very, Very Lucky Sailor nigel1 Off Topic Forum 13 09-11-2011 08:04
So You've Been Very, Very Good . . . Your Boss . . . otherthan General Sailing Forum 6 27-12-2010 21:11
Very Small, Very Efficient Ice Cube Maker Wanted for Sundowners Fuss Plumbing Systems and Fixtures 21 20-07-2010 07:09

Advertise Here


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×

ShowCase vBulletin Plugins by Drive Thru Online, Inc.