Tips on the logistics of set-up on liveaboard

So, I dive in Northern California and never have condensation problems. I soon will take my new D200 in a DX200 housing (S&S) on an air-conditioned liveaboard in the tropics. What sequence do people use to set-up while avoiding condensation. Should I:

1. set-up camera/housing complete in my air-conditioned berth. Go on deck and dive. Rinse, dry, return to air conditioned berth and swap batteries, lenses, ports, etc. Go on deck and dive....

or

2. take housing and camera onto deck separately and wrap camera in a towel while it warms and then wipe off condensation on housing when it warms. Set it up and dive. Return to berth to swap batteries and then repeat?

I don't know... how do you do it?

i always leave my camera on deck all the time, they should have a nice big padded dedicated camera table.

leave it in the housing when it is not in use. The only thing i bring back and forth to cabin would be memory card and lenses. For the lenses, to avoid AC issues it is best to bring them onto deck a good 30 mins or more before you need to put it into the housing to let it warm up.

Do you have a second body or a second camera for land photos? That would be a good way of not having to bring your UW camera in and out of the room/lounge all the time

Air conditioning is your friend. Cool AC air is dry air. If you can assemble and seal your housing inside AC then this is best. When you bring it outside it will fog on the EXTERIOR of the housing but that's no big deal.

If you do have to open stuff outdoors, then warm it up first before exposing it to humid air. Otherwise water will condense on cold surfaces, INCLUDING the inside elements of your lens and camera. Not good. Like Mike says, best to bring them out (sealed in ziploc) for a while to warm up before assembling.

HTH

James

Totally agree with James; air con is your friend.

The only problems I've encountered have been when opening my housing outside of the air-conned saloon - as in just noticing the lens cap still on whilst preparing to jump in.........

...they should have a nice big padded dedicated camera table...

I am with James also - I have always sealed up my kit in the air con - and don't leave it unattended in the rinse tank - that is a favourite disaster area.

Paul C

Thanks for the tips! This was the info that I needed.

As for leaving gear on deck.... in PNG I had all of my gear stolen in the middle of the night despite having a crew member sittting on deck as security (we were near Manus Island). I'm hesitant to do that anymore, but this time I'll be in the Bahamas on a 200 ft NOAA vessel, so I'm not particularly concerned about boarders.

Thanks again!

Scott

Condensation is impacted in part by the ability of the housing to equalize temperature with the surrounding water. Aluminum housings do this very well. Acrylic/polycarbonate not so well. If the internal flash is used alot more heat must be decipated. (This is probably not the case with your D200.) The effectiveness of tropical A/C units is a big unknown for me. How efficiently are they removing moisture ?? I tend to be more worried about them blowing dust around the room than removing water vapor from the air. Since my Nexus housing is aluminum I don't worry about A/C. Doing camera work on deck works fine, as does in a dedicated camera room. For condensation to occur there must be water vapor in the housing & a sufficient temperature differential between the housing & seawater. I tend to minimize this temperature difference vs attempting to minimmize vapor. When moving camera, lenses, flash cards or batteries from A/C room to deck, just give them time to acclimate to new conditions before installing in housing. Whatever works for you I guess. Looks like I'm with Mike on this one.

With some measure of reluctance at saying so, I think the notion of assembling your gear in the AC for the purpose of locking dry air into the housing is an idea a bit overcooked Any pro-sumer or better camera and accessories will do fine in a case or on the photo table at the ambient humidity and temperature of the vast majority of dive locations we visit. And if your gear is at ambient you won't experience any condensations issues provided prolonged exposure to direct sun is minimized Personally I avoid keeping my gear in the AC if possible.

Condensation is only impacted by % humidity. If you start with enough moisture in your housing and camera to be at 90% humidity, and the temp drops, you will go to 100% humitidy and you will get condensation. You get condensation on anything that's cold enough to be at the dew point for the local humidity.

It's not witchcraft. It's not the sun. Reduce the humidity by starting with air as dry as possible, like the AC cabin air.

And protect your $5k camera and $5k vacation with $5.00 worth of dessicant. Why risk it? Why risk even a bit of fog on one dive? get some dessicant.

Maybe I need to write an article about housing fogging. I think it would be a good one as it's a problem on just about every trip I go on. Someone's consumer digicam housing fogs during a dive.

This is an easy issue to resolve if you understand the concept of "dewpoint." The dewpoint is the temperature at which water goes from the vapor phase to the liquid phase. It depends on HOW much water is in the air, and the temperature. Condensation inside a housing depends on the dewpoint, and on the thermal conductivity of the housing materials.

Why?

When you close a housing in 90f moist air (tropical) you're just about at the SVP (saturated vapor pressure). That means that at 90f you are ALMOST at the dewpoint. This is pretty common for the tropics.

When you make a dive and the water temp goes down to 75f or 80f then the housing system starts to lose temperature to equalize w/ the surrounding water. Some materials conduct the heat differently, so they cool off faster.

Glass conducts heat better underwater than acrylic or lexan, so it cools faster. When the glass cools down to the dewpoint temperature, then ALL of the water vapor in the housing condenses onto the inside of the port glass. :-(

The ONLY solution to this problem is to remove the water from the air in some way. One is to use an absorbant medium like silica pack or tampax. The other is to close the housing in dry air (AC) thus trapping air with some water in it that is at a LOWER dewpoint than it will be during the dive.

As posted above in the thread, aluminum housings are good because the aluminum cools the fastest. That means that water will condense on the inside of the aluminum housing shell - which is usually not a problem.

Cheers

James

Maybe I need to write an article about housing fogging. I think it would be a good one as it's a problem on just about every trip I go on. Someone's consumer digicam housing fogs during a dive.

 

This is an easy issue to resolve if you understand the concept of "dewpoint." The dewpoint is the temperature at which water goes from the vapor phase to the liquid phase. It depends on HOW much water is in the air, and the temperature. Condensation inside a housing depends on the dewpoint, and on the thermal conductivity of the housing materials.

 

Why?

 

When you close a housing in 90f moist air (tropical) you're just about at the SVP (saturated vapor pressure). That means that at 90f you are ALMOST at the dewpoint. This is pretty common for the tropics.

 

When you make a dive and the water temp goes down to 75f or 80f then the housing system starts to lose temperature to equalize w/ the surrounding water. Some materials conduct the heat differently, so they cool off faster.

 

Glass conducts heat better underwater than acrylic or lexan, so it cools faster. When the glass cools down to the dewpoint temperature, then ALL of the water vapor in the housing condenses onto the inside of the port glass. :-(

 

The ONLY solution to this problem is to remove the water from the air in some way. One is to use an absorbant medium like silica pack or tampax. The other is to close the housing in dry air (AC) thus trapping air with some water in it that is at a LOWER dewpoint than it will be during the dive.

 

As posted above in the thread, aluminum housings are good because the aluminum cools the fastest. That means that water will condense on the inside of the aluminum housing shell - which is usually not a problem.

 

Cheers

James

James

Thank you for that clear explanation, appreciated by a 'physics' numpty like me!

Reduce the humidity by starting with air as dry as possible, like the AC cabin air.

I'm sorry, and I don't mean to be unkind, but I find the whole assertion that it is necessary to lock AC'd air into your housing, absurd Why make it more difficult or scary than it has to be?

No problem Iggy - you are free to choose where and when you put your housing together. My advice is free and you certainly don't have to follow it. If others choose a different method, then that's fine too.

What matters is whatever works best for YOU.

Cheers

James

The biggest chance for fogging is for a P/S camera in an acrylic housing, since the onboard flash probably fires for every shot. This constantly produces additional heat in the housing which must be disipated. Get out the silia gel packs for this one.

No problem Iggy - you are free to choose where and when you put your housing together.

No ill-will intended James. And that's not forum induced gentility, I really mean it

Hi Iggy,

I work offshore (10+ years) and have plenty of experience w/ condensation and corrosion. I respectfully disagree that just because something has been done for 20 years does not make it the best way :-)

I think it's a legit comment (even from someone with authority) to say that it's better to keep and/or open microelectronics inside in an airconditioned space rather than leaving them on deck.

Cheers

James

Interesting

I've only had fog issues two times.

First in the Bahamas in scorching heat. My mistake I believed was to assemble my housing inside in the air-conditioning. Leaving it outside the rest of the trip (in the shade) I never had a problem. As indeed I never had in any hot environments where I have left it outside.

The other was actually in Northern Ca. (Monterey). This was during the beach photo contest. My dome fogged up. Air temp. about 70, water in the low 50s. I resorted to floating on my back on the surface with my housing on my chest. Took the sun about 14 minutes to burn away the fog. Nearby was raft of Sea Otters; some on their backs. Once I got back to shore some guy complained that I had resumed my dive before he maneuver out their to take a photo of this for the contest. He was sure that it would have won the contest and was upset that I didn't stay to pose for him.

Does AC actually reduce the humidity by that much?

I would tend to agree that keeping electronics in an A/C environment may be best. But the key word here is "keeping". We as divers do not do that - we're moving our rigs inside, outside, AC, no AC, in the water....

If you let temperature/humidity conditions stabilize you will be alot less likely to have a condensation problem. This means working on deck or in a room at/near ambient temperature. And keep your rig out of direct sun.

Been on numerous live-aboards with both Ikelite and Canon housings and as long as security is not an issue (which it never has been) I leave all camera gear outside on the photo table or shelves underneath. If I have a need to bring some portion of the set-up inside AC'd areas I always take it back out in time to adjust. Had a condensation issue once at Sunset House where I had the housing outside on a table and immediately put the camera inside from the AC'd room. As soon as I saw it I knew what I had done. Outside on the table (shaded area) and covered with a dry towel has worked for me. I have silica packs on hand but have never had to use them.

YMMV

Jeff

It's rare (and with some trepidation) that I even consider disagreeing with James about anything, but I'm with iggy and jcclink on this one. I do a lot of liveaboard trips in the tropics (and nowhere else), and I see a lot of people having trouble with condensation. Invariably, it seems, this involves housings (usually acrylic, but sometimes aluminum) and other components that have been chilled by being held in an air conditioned cabin. I see people trying to deal with this by sticking bags of silica gel, tampons, and tissues around the housing, muttering imprecations, even prayer. And I tell them, just keep your housing, camera and lenses out of your cabin.

At home, my cameras and lenses live in air-conditioned and dehumidified powered dry boxes in a room that is air conditioned most of the time. These are absolutely wonderful if you live in the tropics and don't like fungus growing inside your lenses! On the boat, however, it's a major rule that my cameras, lenses, and housings stay out of heavy cabin air conditioning. (Inside is fine, as long as it isn't an air conditioned space, and I don't leave anything in the sun.) If I need to keep stuff in an a/c cabin, I let it warm to non-a/c room temperature for at least a couple of hours before opening anything up, changing lenses, etc. I've never had trouble with fogging. (I have an aluminum housing by Subal. I don't use silica gel or other dessicants in the housing.)

I think I understand the point James is making, but I'm not sure it applies to most liveaboards that I've been on. James seems to be assuming that a/c cabin air is really dry, which simply isn't always the case on a boat. With a damp towel and a couple of wet suits hanging in the room, and water on the floor of an en suite shower/bath, the humidity in an a/c cabin can be at least as high as it outside or in a simply ventilated space, and some times much higher.

Frogfish