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Scuba Forum / General / March 2004Negative pressure
I'll be flying out of the US and want to store my Oly 5050 digicam inside it's UW housing to save space. It'll travel in my carry-on bag (I never check stuff). There's no good way to put the camera in without sealing the housing. I know the housing is good to 130 feet of positive pressure, but I wonder if there is any danger of the slight negative pressure in the cabin damaging any of the seals on the housing? My old Pelican cases had purge values to deal with this issue, but the Oly housing doesn't. Thoughts? TIA, Dave -- "Every normal man must be tempted at times to spit upon his hands, hoist the black flag, and begin slitting throats." - HL Mencken >I'll be flying out of the US and want to store my Oly 5050 digicam inside >it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 5 lines] > >Thoughts? Take out the O-rings safe diving, bullshark > >I'll be flying out of the US and want to store my Oly 5050 digicam inside > >it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 7 lines] > > Take out the O-rings Thanks. One or both? > > >damaging any of the seals on the housing? My old Pelican cases had purge > > >values to deal with this issue, but the Oly housing doesn't. [quoted text clipped - 4 lines] > > Thanks. One or both? Both >replace spamblock with my family name to e-mail me #I'll be flying out of the US and want to store my Oly 5050 digicam inside #it's UW housing to save space. It'll travel in my carry-on bag (I never #check stuff). There's no good way to put the camera in without sealing the #housing. I know the housing is good to 130 feet of positive pressure, but I #wonder if there is any danger of the slight negative pressure in the cabin #damaging any of the seals on the housing? My old Pelican cases had purge #values to deal with this issue, but the Oly housing doesn't. # #Thoughts? # #TIA, # #Dave # # You won't damage the o-rings or seals, but you will almost certainly have problems opening the housing after you land (which is why Pelican cases have vent valves). Remove the main o-ring before you fly. Alan > #I'll be flying out of the US and want to store my Oly 5050 digicam inside > #it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 17 lines] > > Alan I thought you had to pack it in water "Alan Street" <alan@nonono_irsi.com> wrote in message news:150220041455314758% > You won't damage the o-rings or seals, but you will almost certainly > have problems opening the housing after you land (which is why Pelican > cases have vent valves). Remove the main o-ring before you fly. > > Alan I would think that problem would exist ONLY if you open it at altitude. If you close it on the ground...and don't open it until you're again on the ground, the pressure inside shouldn't change, should it? > "Alan Street" <alan@nonono_irsi.com> wrote in message > news:150220041455314758% [quoted text clipped - 8 lines] > the > ground, the pressure inside shouldn't change, should it? It depends on where you land. Think LA to Denver.  SignatureTom Thackrey www.creative-light.com tom (at) creative (dash) light (dot) com do NOT send email to jamesbutler@willglen.net (it's reserved for spammers) "Tom Thackrey" <use.signature@nospam.com> pounded away at his keyboard resulting in: :It depends on where you land. Think LA to Denver. No it doesn't. Mine was hard to open after flying Toronto to Cozumel. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ > "Alan Street" <alan@nonono_irsi.com> wrote in message > news:150220041455314758% [quoted text clipped - 7 lines] > If you close it on the ground...and don't open it until you're again on the > ground, the pressure inside shouldn't change, should it? I would think so too, but I FINALLY found the Oly documentation (page 147, thank-you-very-much) and they say to pull both o-rings before flying. I'll just put them in one of the little bags they give you for lubricating them and all should be fine. Thanks all! >I would think that problem would exist ONLY if you open it at altitude. >If you close it on the ground...and don't open it until you're again on the >ground, the pressure inside shouldn't change, should it? Only if it remains sealed. But underwater cases are designed only for the situation where pressure is higher outside the case than inside, where pressure forces the case halves to close more tightly on the O-ring. In a situation where the pressure inside the case is higher, the case halves are forced apart and the seal will leak, equalizing the pressure. Thus, as the plane climbs, the cabin altitude rises to 6000-8000 feet, and the housing will leak outward enough to bring the pressure inside it to somewhere near that level. Then when the plane descends, the housing clamps onto the O-ring and fails to leak. When you get back on the ground, you've got a substantial pressure difference between inside and outside. Dave #"Alan Street" <alan@nonono_irsi.com> wrote in message #news:150220041455314758% #> You won't damage the o-rings or seals, but you will almost certainly #> have problems opening the housing after you land (which is why Pelican #> cases have vent valves). Remove the main o-ring before you fly. #> #> Alan # #I would think that problem would exist ONLY if you open it at altitude. #If you close it on the ground...and don't open it until you're again on the #ground, the pressure inside shouldn't change, should it? # # Not necessarily. Some seals will hold pressure from either direction, but many seals used in housings are designed to withstand external pressure and vent internal pressure. Since the cabin of an airplane is pressurized to an equivalent of ~7000 ft, many housings will vent when the plane is at altitude and seal upon descent. Anyone who has used a Pelican case onboard has seen this (as an aside, venting a Pelican case next to a TSA inspector can be great fun.... if you're not in a hurry to catch your next plane ;-). Alan "Mark M" <mjmorganReeMoov2@cox.net> pounded away at his keyboard resulting in: :I would think that problem would exist ONLY if you open it at altitude. :If you close it on the ground...and don't open it until you're again on the :ground, the pressure inside shouldn't change, should it? My observations refute your theory. I don't know if the pressure changes, but I know that it took me two trips to learn that if I closing the housing, it is hard to open when I arrive at my destination. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ >"Alan Street" <alan@nonono_irsi.com> wrote in message >news:150220041455314758% [quoted text clipped - 7 lines] >If you close it on the ground...and don't open it until you're again on the >ground, the pressure inside shouldn't change, should it? The housings are designed to keep pressure out, not keep pressure IN. Taking such a housing to altitude will cause it to vent slightly, and it doesn't take much "slight" to make it impossible to open. When I fly with my Pelican, the lid is ALWAYS compressed and it is impossible to open until I release the vent. --- Rich http://richlockyer.tripod.com/ > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] > damaging any of the seals on the housing? My old Pelican cases had purge >SNIP< I have flown with my Nikonos camera in checked bags, then used it underwater. No problems with seal damage, nor with opening the camera on land. I did take normal care of the seal, and grease it before use as directed in the manual. I don't know what pressure is maintained in the checked baggage area, but I suspect it will be the same as or less than in the passenger cabin. SignaturePhilip Stripling | email to the replyto address is presumed Legal Assistance on the Web | spam and read later. email to philip@ http://www.PhilipStripling.com/ | my domain is read daily. > > I'll be flying out of the US and want to store my Oly 5050 digicam inside > > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 10 lines] > checked baggage area, but I suspect it will be the same as or less than in > the passenger cabin. I haven't had any problem with my UW cameras either, but the Oly housing has a LOT more volume and a ton of o-ring sealed controls. I'm afraid that either I'll never be able to get it open again, or that one of the little o-rings will slip out if place and leak or get jammed. After doing some repacking today, it looks like I'll be able to take the divider out of my Domke bag, use it for the accompanying gear, and pack the camera in the housing on the side with the main o-ring removed. Thanks all, Dave > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] > damaging any of the seals on the housing? My old Pelican cases had purge > values to deal with this issue, but the Oly housing doesn't. Interesting question. On my trips, I pack the housing with the door open with clothes packed around it to keep it from getting damaged. The suggestion that others have made to remove the main O-ring sounds like an even better idea however. -Eric "Eric" <eric@nospam.org> pounded away at his keyboard resulting in: : Interesting question. On my trips, I pack the housing with the door :open with clothes packed around it to keep it from getting damaged. The :suggestion that others have made to remove the main O-ring sounds like an :even better idea however. Sounds pretty labour intensive to me. I use the leave the housing open. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] > damaging any of the seals on the housing? My old Pelican cases had purge > values to deal with this issue, but the Oly housing doesn't. First off, there is no such thing as "negative pressure" The cabin pressure in an airliner is about 8,000' when the aircraft is at 30,000 - 35,000 feet. As a rule of thumb, it is about 1" (Hg) per 1,000 feet of altitude at low altitudes .... so if the pressure in the enclosure is 1 atmos. the pressure against the seals will be about 8" Hg ... about 0.3 atmospheres. It is pressing in the sense opposite that when under water, but surely the enclosure will tolerate that? Does the manufacturer have any information at their website about carrying on aircraft? Is there something on the enclosure you can leave open? Cheers, Alan. Signaturee-meil: there's no such thing as a FreeLunch. >I'll be flying out of the US and want to store my Oly 5050 digicam inside >it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] >damaging any of the seals on the housing? My old Pelican cases had purge >values to deal with this issue, but the Oly housing doesn't. I remove the O-ring and pack it separately. --- Rich http://richlockyer.tripod.com/ Dave left this mess on Sun, 15 Feb 2004 16:16:05 -0600 for The Way to clean up: >I'll be flying out of the US and want to store my Oly 5050 digicam inside >it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 5 lines] > >Thoughts? Never seal your casing on a plane. Next? Tao te Carl "It takes a village to have an idiot." - Carl (c) 2003 (Kudos to Cap'n Jim Wyatt for this link) BEFORE you ask a dumb-a.s question here...http://www.speakeasy.org/~neilco/bart.gif > >I'll be flying out of the US and want to store my Oly 5050 digicam inside > >it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 5 lines] > > > >Thoughts? This is all kind of irrelevant isn't it? How could there be negative pressure in the cabin? If there is, it probably means that there's been a serious disaster and you're probably going to crash anyway. Planes always maintain pressure in the cabin, it's handy to stop people from passing out etc. >This is all kind of irrelevant isn't it? How could there be negative >pressure in the cabin? If there is, it probably means that there's been a >serious disaster and you're probably going to crash anyway. Planes always >maintain pressure in the cabin, it's handy to stop people from passing out >etc. Only to 6,000 to 8,000ft, and only really guaranteed to 10,000ft Go ahead.... take a bottle of suntan lotion from sea level to 10,000ft and open it up. There is a significant pressure difference, and it doesn't take much to render a housing impossible to open. --- Rich http://richlockyer.tripod.com/ > Only to 6,000 to 8,000ft, and only really guaranteed to 10,000ft > Go ahead.... take a bottle of suntan lotion from sea level to 10,000ft > and open it up. > > There is a significant pressure difference, and it doesn't take much > to render a housing impossible to open. That's very interesting. I didn't know that. I stand corrected. I assumed that since the cabin was pressurised, that the sea level pressure would be maintained. However after doing some more research I now understand that the pressure is allowed to fall, just not as low as the pressure outside (for obvious reasons). >I'll be flying out of the US and want to store my Oly 5050 digicam inside >it's UW housing to save space. ... There's no good way to put the camera in without sealing the housing. ... Remove the O-ring(s). Replace them before diving. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > >I'll be flying out of the US and want to store my Oly 5050 digicam inside > >it's UW housing to save space. ... There's no good way to put the camera in > without sealing the housing. ... > > Remove the O-ring(s). Replace them before diving. Got to remember the second part - that'd be the kicker ;) > > >I'll be flying out of the US and want to store my Oly 5050 digicam inside > > >it's UW housing to save space. ... There's no good way to put the camera in [quoted text clipped - 3 lines] > > Got to remember the second part - that'd be the kicker ;) Put a tag on the housing reminding you to put the O rings back in, also on the camera. Nobody can remember everything, a reminder is all that is needed. > > Got to remember the second part - that'd be the kicker ;) > > Put a tag on the housing reminding you to put the O rings back in, also on > the camera. Nobody can remember everything, a reminder is all that is > needed. or remove and loop the door o-ring and throw it in the case with the camera, near the LCD for models not totally transparent, should be a good visual reminder... or put a small one in the battery compartment :-) "R Benner" <bennerBOGUS@personainternet.com> pounded away at his keyboard resulting in: :Put a tag on the housing reminding you to put the O rings back in, also on :the camera. Nobody can remember everything, a reminder is all that is :needed. Another argument in favour of leaving the seals in and the housing open. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ >Another argument in favour of leaving the seals in and the housing >open. > O-ring inspection should be a basic, never forgotten check list item right up there with: -is there air in the tank -is my mask on my face before I jump in -did I remember to put on my weight belt. any photog who fails to check his o-ring before EVERY dive is asking for a flood. > Buff5200 <BUFF5200@aol.com> pounded away at his keyboard resulting in: :O-ring inspection should be a basic, never forgotten check list item :right up there with: [quoted text clipped - 5 lines] :any photog who fails to check his o-ring before EVERY dive is asking for :a flood. On my last trip we had these big heavy tanks so any concept of extra weight was a non-starter. But, exactly what does one check an o-ring for? And, how does one conduct such a check? Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ "Dan Bracuk, CTHD" schrieb: > On my last trip we had these big heavy tanks so any concept of extra > weight was a non-starter. But, exactly what does one check an o-ring > for? And, how does one conduct such a check? Look for scars, stretch it, look for tiny cracks. Check roundness, if a bit square, and no replacement available, massage it gently to it's original form, or close. Matthias > Look for scars, stretch it, look for tiny cracks. Check roundness, if a > bit square, and no replacement available, massage it gently to it's > original form, or close. Yet another newsgroup thread degenerates into a sex thread... The recommendation is to remove the main O-ring from an underwater camera housing when traveling by air with the housing. The objection is that you might forget to replace the O-ring. Get serious! If you don't inspect your housing, checking and re-lubing the O-ring before every day's diving, you're going to flood anyway. And if you DO inspect, you'll hardly overlook a missing O-ring! Aquire and practice the right habits of caring for U/W photo equipment or be prepaired to throw away lots of money replacing it. This gear is NOT like your old Kodak "Brownie" - you can't just pull it out of the closet once an year and expect it to work without a bit of TLC. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. >The recommendation is to remove the main O-ring from an underwater camera >housing when traveling by air with the housing. > >The objection is that you might forget to replace the O-ring. > >Get serious! Dan gets paid to be contrary. If he weren't the stereotypical polite Canadian, we'd call him a troll. --- Rich http://richlockyer.tripod.com/ Rich Lockyer <rlockyer@linkline.DONTSPAMME.com> pounded away at his keyboard resulting in: :Dan gets paid to be contrary. The objection of "you might forget to replace it" came from someone else. My objection is that it is more labour intensive than necessary. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ hammond@not@peek.ssr.hp.com (Charlie Hammond) pounded away at his keyboard resulting in: :The recommendation is to remove the main O-ring from an underwater camera :housing when traveling by air with the housing. [quoted text clipped - 12 lines] :is NOT like your old Kodak "Brownie" - you can't just pull it out of :the closet once an year and expect it to work without a bit of TLC. Depends on the camera of course. On my Reefmaster, the o-ring is not designed to be removed or lubricated. Also, while I have not tried it for a year, I did pull it out of the closet after nine months and it worked. But those of you who like labour intensive cameras have other options available. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ Grumman-581 schrieb: > > Look for scars, stretch it, look for tiny cracks. Check roundness, if a > > bit square, and no replacement available, massage it gently to it's > > original form, or close. > > Yet another newsgroup thread degenerates into a sex thread... Evolves! Matthias > Buff5200 <BUFF5200@aol.com> pounded away at his keyboard resulting in: > :O-ring inspection should be a basic, never forgotten check list item [quoted text clipped - 10 lines] > weight was a non-starter. But, exactly what does one check an o-ring > for? And, how does one conduct such a check? I will squeeze the o-ring between the thumb and crook of the forefinger of one hand and pull it through with the other. After more than a full 360 (it's hard to tell exactly when it's been through for one rotation), I'll turn the o-ring around and pull it through the other way. I'm feeling for embedded grit, abrasion, slices that open up under the pressure of my thumb and finger, anything that isn't completely smooth. Then I'll put the o-ring on the back plate, clamp it onto the main housing, and examine the sealing surface of the o-ring, looking for anything not completely uniform. Ikelite clear housings make this rather easy. Regards, Ross -- Ross Bagley http://rossbagley.com/rba "Security is mostly a superstition. It does not exist in nature... Life is either a daring adventure or nothing." -- Helen Keller #"Dan Bracuk, CTHD" <NOTbracuk@pathcom.com> writes: # #> Buff5200 <BUFF5200@aol.com> pounded away at his keyboard resulting in: #> :O-ring inspection should be a basic, never forgotten check list item #> :right up there with: #> : #> :-is there air in the tank #> :-is my mask on my face before I jump in #> :-did I remember to put on my weight belt. #> : #> :any photog who fails to check his o-ring before EVERY dive is asking for #> :a flood. #> #> On my last trip we had these big heavy tanks so any concept of extra #> weight was a non-starter. But, exactly what does one check an o-ring #> for? And, how does one conduct such a check? # #I will squeeze the o-ring between the thumb and crook of the #forefinger of one hand and pull it through with the other. After more #than a full 360 (it's hard to tell exactly when it's been through for #one rotation), I'll turn the o-ring around and pull it through the #other way. I'm feeling for embedded grit, abrasion, slices that open #up under the pressure of my thumb and finger, anything that isn't #completely smooth. # #Then I'll put the o-ring on the back plate, clamp it onto the main #housing, and examine the sealing surface of the o-ring, looking for #anything not completely uniform. Ikelite clear housings make this #rather easy. # #Regards, #Ross # # Welcome back, Ross! .. >> Remove the O-ring(s). Replace them before diving. > >Got to remember the second part - that'd be the kicker ;) It will be instantly apparent if you forget. <grin> SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 9 lines] > > Dave Underwater housings are designed to keep water out. The pressure outside the housing (in the water) is greater than inside the housings. At a high altitude the pressure outside the housing is less than inside the housing. Therefore there is force from the inside of the housing pushing to get out rather than water from the outside pushing to get into the housing. The design of the seals & valves may not be designed to handle this reverse pressure. You may even damage the integrity of the seals or valves. I would check with the manufacturer. Ihor > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] > damaging any of the seals on the housing? My old Pelican cases had purge > values to deal with this issue, but the Oly housing doesn't. negative pressure? i don't think there will be a vacuum in your plane...and if there is, your camera housing will be the least of your problems. commercial flights should have a cabin pressure of at least the equivalent of an 8000 ft altitude. if your ears can stand the pressure in an airplane cabin, then surely your housing can too. >>I'll be flying out of the US and want to store my Oly 5050 digicam inside >>it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 13 lines] > of an 8000 ft altitude. if your ears can stand the pressure in an airplane > cabin, then surely your housing can too. Jim, As someone else pointed out, I don't think it is an issue of withstanding the "pressure" as much as which direction the pressure is coming from. The seals and housing are designed to withstand pressure from outside pushing in. If the camera housing is sealed at sea level and then ascends to 8000 ft (cabin pressure), the pressure inside the housing will be reverse from what it is normally designed to withstand. Will that damage the seal or housing? May or may not. I guess that is main question. Others have suggested removing the O-ring for the trip which would solve that problem (as long as the O-ring were replaced prior to the dive). In my situation, I live at 1100 ft above sea level. I have never had a problem when loading the camera at home and then opening the housing at sea level, but I could tell there was a pressure difference. In that case, there was a slight "vacuum" in my camera housing. Andy Signature"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." George Orwell nitespark@h8spam.cox.net writes: >The seals and housing are designed to withstand pressure >from outside pushing in. If the camera housing is sealed at sea level >and then ascends to 8000 ft (cabin pressure), the pressure inside the >housing will be reverse from what it is normally designed to withstand. > Will that damage the seal or housing? May or may not. I guess that >is main question. It shouldn't damage the housing, since it's intended for more pressure difference than an airplane flight will generate. The problem is that as the cabin pressure drops to 8000 ft altitude equivalent, the housing will expand to the point that the seal will leak, relieving the pressure difference (since it isn't designed to seal against higher internal pressure). Then when the airplane descends, the increase in pressure will clamp the housing tightly shut on the O-ring, making a good seal. No damage will result, but you may not be able to get the housing open at all. (4 PSI pressure difference times the surface area of the housing can be a lot of pressure clamping the housing closed). >In my situation, I live at 1100 ft above sea level. I have never had a >problem when loading the camera at home and then opening the housing at >sea level, but I could tell there was a pressure difference. In that >case, there was a slight "vacuum" in my camera housing. Now imagine you loaded the camera into the housing at 8000 feet in the mountains, then drove to sea level. It would take about 8 times as much force to get it open. Dave > nitespark@h8spam.cox.net writes: > [quoted text clipped - 26 lines] > > Dave take it straight in and you get a leak, even shallow water, it will suck it in. > > Now imagine you loaded the camera into the housing at 8000 feet in the > > mountains, then drove to sea level. It would take about 8 times as much [quoted text clipped - 4 lines] > take it straight in and you get a leak, even shallow water, it will suck it > in. I guess a funnier wording would have been... a leak under those conditions would really suck in water. ;-) >>>Now imagine you loaded the camera into the housing at 8000 feet in the >>>mountains, then drove to sea level. It would take about 8 times as much [quoted text clipped - 10 lines] > I guess a funnier wording would have been... a leak under those conditions > would really suck in water. ;-) Booooooo Hissssss Signature"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." George Orwell > nitespark@h8spam.cox.net writes: > [quoted text clipped - 4 lines] > > Will that damage the seal or housing? May or may not. I guess that > >is main question. good point andy. > It shouldn't damage the housing, since it's intended for more pressure > difference than an airplane flight will generate. The problem is that [quoted text clipped - 15 lines] > mountains, then drove to sea level. It would take about 8 times as much > force to get it open. the pressure gradient as one ascends is not linear...and the pressure at 1000 ft is certainly not 8 times the pressure at 8000 ft. >> I'll be flying out of the US and want to store my Oly 5050 digicam inside >> it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 11 lines] >of an 8000 ft altitude. if your ears can stand the pressure in an airplane >cabin, then surely your housing can too. A misconception here: Your ears can not stand the pressure differential between seal level and 8000 feet, but they don't have to. The pressure is equalized through the eustachian tube so the pressure inside is pretty much equal to the outside. Our sinuses are so sensitive that it only takes a few inches of water pressure to break bone. Any one who has gone flying with blocked sinuses can verify how painful it can be. I went flying with what I though was a light cold. As I climbed it actually felt good, but unfortunately that was not the case when I started down to land. I could only descend a couple thousand feet at a time and then had to wait till the pressure finally equalized. It took me longer to get down from two miles up than it did to make the trip. Any one who lives in the mountains can tell you what pressure changes can do. Exploding bags of potato chips, soda bottles... When you live at 9,000 feet and shop at 5000 (Denver) you find that just 4000 feet can make for an interesting experience at times. <:-)) How well the waterproof housing would fare? I don't know, but *I'd guess* it would survive. I'd sure hate to have it pop on a commercial flight in today's climate though. The air would probably leak out, but not back in. It might be a real bear to open later. <:-)) Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com > I'll be flying out of the US and want to store my Oly 5050 digicam inside > it's UW housing to save space. It'll travel in my carry-on bag (I never [quoted text clipped - 3 lines] > damaging any of the seals on the housing? My old Pelican cases had purge > values to deal with this issue, but the Oly housing doesn't. Thanks to everyone for their input on this. Since it's a new housing and I didn't want to mess with servicing it quite yet, I ended up leaving the o-rings in, but propped the door open and used the wrist strap to keep it from flopping around. Everything traveled safely and I ended up getting some nice shots both in and out of the water: http://www.webkatz.net/Mexico/Cozumel04.html I noticed that if you're not underwater, the housed camera gets amazingly hot in the Caribbean sun. It almost got too hot to touch after just floating around for about 10 minutes. Sitting around the beach, the un-housed camera didn't heat up at all. I also experienced some of the "negative pressure" problem I was worried about - I threw the housed camera in my black beach bag for part of the afternoon and then had a hell of a time getting it open in our air-conditioned hotel room. Anyway, I appreciate the advice, love the 5050, and had a blast in Cozumel. Dave "Dave" <webkatz@eudoramail.com> pounded away at his keyboard resulting in: :Everything traveled safely and I ended up getting some :nice shots both in and out of the water: :http://www.webkatz.net/Mexico/Cozumel04.html There are indeed some nice shots. Your purple fish with the blue tail looks like a yellow tailed damselfish. Carnival week in Cozumel is fun, isn't it. Dan Bracuk If at first you don't succeed, you run the risk of failure. The Best of rec.scuba http://www.pathcom.com/~bracuk/RecScuba/ > "Dave" <webkatz@eudoramail.com> pounded away at his keyboard resulting > in: [quoted text clipped - 6 lines] > > Carnival week in Cozumel is fun, isn't it. Thanks. Carnaval was an absolute hoot. We went a couple a nights and had a great time. |
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