A completely submersible cache? (guidance needed)

[TheStouffville5]

I am looking to create a cache that is completely underwater. It would be approximately 6 feet under water at most. As the lake level goes down it would be around 2 feet at best. It doesnt have to be fancy, in fact practical is better than fancy, given where it will be...Im thinking of PVC pipe closed at one end with some cement inside for weight and then a screw top on the other end. but my concern is that the constant water pressure would evenually work its way inside.

 

I know there are rubber seals for the screw top but Im hoping someone can actually say " ive built one and this is what I learned".....

 

Does anyone have specific expereince they can draw on to provide some guidance? I know there are many "waterproof" conatiners out there. But this one would be actually in an underwater environment until removed for signing.

Links or video or anything would be awesome.

Thanks

[+Mr. Wilson & a Mt. Goat]

I've seen plastic preforms attached to a bag of rocks, it worked ok, water still got in after awhile. Another good idea is to have something that can be clipped/unclipped from something (usually a buoy), though the ones I've found like this were dive slates.

Water will make it's way inside the first layer for sure, but you could dry containers within containers for added water protection.

[+cerberus1]

Enjoy maintenance runs?

Every underwater hide we've found was wet inside.

Many finders can't keep land hides dry, sooner or later someone's not taking the time to dry hands/wipe seals, opening the container to access the log.

 

We've seen some that were a stage in a multi.

Aluminum dog tags or plastic piece with coords inside anything would work then.

[+WarNinjas]

I found a pipe sticking up in the bay a ways off shore. I used a milk crate and wired a bunch of weights inside of it. Then inside of the crate I tied a pelican style box. Inside of that was a Lock N' Lock and then a water bottle preform in that. It got all covered in green moss on the outside but was fine on the inside for many months. Then PG&E cut it off and put something over the pipe. I had no idea it was a PG&E pipe as it just looked like something random sticking out of the water. I moved it but think it would still be going fine if not removed.

[+niraD]

I've found an ammo can that was submerged. It worked well unless someone caught a plastic bag in the seal when closing it; then the plastic wicked moisture into the ammo can.

 

I've seen a design that I think would work. The outer container is a section of PVC pipe, with a cap glued to one end and a ball valve glued to the other end. The PVC pipe (and thus, the cap and ball valve) have to be big enough that a match safe or preform can fit into it. The log goes into the match safe or preform. The match safe or preform goes into the PVC pipe, and the ball valve end of the PVC pipe is tied to a weight. The idea is for the pipe to float with the ball valve down, and with the cap of the match safe or preform up. If the ball valve leaks (or isn't closed properly), then air pressure keeps water out of most of the pipe. The match safe or preform inside should keep the log dry.

 

But I've never actually found a cache like that.

[+cheech gang]

Weighted ammo can in water at end of cord, sealed lock-n-lock container inside the ammo can. Foolproof only until the inner box is not closed properly.

 

I can't imagine there is ANY configuration that some fool can not screw up...

[+coachstahly]

You can use a diving slate as your log and water inside the container wouldn't matter. You'll probably have to clean it every once in a while. I have a 5/5 multi with multiple underwater stages but I hid it late last summer and won't be able to check on it until Memorial Day at the earliest. For one stage I used a hard plastic water bottle with a screw top (no flip top or "straw", just a cap), loaded with sand, and a matchstick container inside on top, secured to an old wooden pole, that used to be an advertising sign in the main channel, with a wire fishing leader. Another stage was a hand punched dog tag. Another stage is a diving slate piece. None of them are deeper than 4 feet.

[+J Grouchy]

Seems like a container within a container would work best...adding a level of redundancy to help keep water away from the log sheet. I heard that Nalgene (authentic Nalgene...not a knock-off brand) makes for a good underwater container...so perhaps putting a preform or waterproof matchstick container inside one of those would work well.

[+Isonzo Karst]

I own a submerged cache, and have owned several through the years.

 

Don't try to keep them dry, go ahead let them be wet. This works fine, and takes care of buoyancy issues as well.

I have used UW dive light battery canisters for dry UW caches. This will work, until someone gets the inside wet by handling the cache while they're wet. Because that's what is always going to happen, why fight it?

 

My current UW cache is an old ammo can, had holes rusted through, so I drilled more holes such that water moves through it well, and it drains as it's lifted out of the water. Has a divers slate for a log.

It's cabled to an old bridge pier, tends to sit on the bottom.

Works fine

[+BAMBOOZLE]

Use a stainless steel water bottle....weight it with fishing sinker lead. Put your log in a match safe or attach a line to the inside of the cap and suspend a bison containing your log. We have found these water bottles dry on the inside and barnacle encrusted on the outside.

[+kunarion]

Does anyone have specific expereince they can draw on to provide some guidance? I know there are many "waterproof" conatiners out there. But this one would be actually in an underwater environment until removed for signing.

A local cache was a big ammo box in a submerged hollow tree stump. The can was half-filled with concrete for weight. It was no more wet inside than any other ammo box around here. A small box in that box might have worked OK, too. The whole thing washed away in a flood.

[+Trucker Lee]

Just like holding glass upside down in the sink, the top should be sealed and the bottom can be open. Weight around the outside of the container and tether so the cache can be reached through the open bottom. A pickle bucket will easily conceal a small ammo can this way, the ammo can will be enough to keep things dry as cachers return to shore to trade and sign. No extra tools needed, so would most likely rate as a 3.

[+cerberus1]

My current UW cache is an old ammo can, had holes rusted through, so I drilled more holes such that water moves through it well, and it drains as it's lifted out of the water. Has a divers slate for a log.

It's cabled to an old bridge pier, tends to sit on the bottom.

Works fine

This looks like the best idea.

All of the ammo cans we got at geowoodstock had faulty seals, so that's a good option for 'em rather than fixing.

 

May be a dumb question, but do you simply erase the divers slate when the log's full?

[+Isonzo Karst]

but do you simply erase the divers slate when the log's full?

 

You could. On mine, it'll be years before that's an issue. It may never be an issue; because the cache and hence the slate are in moving water, I guess that it will tend to gently erase over time.

The slate needs to be attached to the cable that holds the cache. It's easy for people to lose.

 

[+cerberus1]

Thanks !

[+wmpastor]

Enjoy maintenance runs?

Every underwater hide we've found was wet inside.

...

Does it have to be dry? What about the dive slates for signing? They're made to be wet all the time.

[+cerberus1]

Enjoy maintenance runs?

Every underwater hide we've found was wet inside.

...

Does it have to be dry? What about the dive slates for signing? They're made to be wet all the time.

Did you read the last two posts above yours?

[+ecanderson]

There are expansion plugs designed for the end of PVC or other pipe. The plugs have threaded rods (big screws, really) down the center with a wing nut. As the wing nut is tightened against a washer on one end, a washer on the other end helps and begins to try to compress the rubber stopper. As it does so, it expands laterally to fit tightly into the pipe. You can seal the other end with PVC cement.

 

The only gotcha here is that you have to trust the finder to take time to screw the wing nut back down tightly enough to create a proper seal. I've seen a couple of these that worked well, and a couple that didn't. You need a soft (low durometer) rubber for best results.

 

Picture something like one of these things http://www.alibaba.com/product-detail/rubber-compression-stopper_1804395703.html?s=p , small end inserted into the pipe, with washers on both ends, and a bolt running from small out the large end, with a wing nut. Turn the nut and expand the rubber, and you have a seal. They make them pre-built, but I couldn't spot one out on the net . Probably using the wrong nomenclature.

[+threenow24]

My underwater cache (PMO when it's disabled) sits in about two feet of water. It consists of a smallish lock-n-lock inside another larger lock-n-lock. I filled the outer one with cement and lead weights to keep it on the lake bottom, with a space formed for the smaller container to sit in. I take it out every fall (I live in Minnesota where the lakes freeze, I haven't wanted to risk the cache being frozen in the ice and then being uprooted and moved when the ice goes out in the spring).

Every year the outer container has had water in it, due to something like a piece of seaweed or grain of sand getting in the seal and causing a leak, but the inner has always been dry, next month will mark it's 6th year.

The Geocachingvlogger posted a

on it a few years ago if you wanted to check it out.

As I said, I pull this out every year and clean and dry the outer container. Would the inner cache still be dry if it had sat out on the lake bottom all that time? I believe it would be, but of course it all depends on the finders taking the time to make sure the boxes don't have stuff in the seals when they're done.

[+cerberus1]

There are expansion plugs designed for the end of PVC or other pipe. The plugs have threaded rods (big screws, really) down the center with a wing nut. As the wing nut is tightened against a washer on one end, a washer on the other end helps and begins to try to compress the rubber stopper. As it does so, it expands laterally to fit tightly into the pipe. You can seal the other end with PVC cement.

 

The only gotcha here is that you have to trust the finder to take time to screw the wing nut back down tightly enough to create a proper seal. I've seen a couple of these that worked well, and a couple that didn't. You need a soft (low durometer) rubber for best results.

 

Picture something like one of these things http://www.alibaba.com/product-detail/rubber-compression-stopper_1804395703.html?s=p , small end inserted into the pipe, with washers on both ends, and a bolt running from small out the large end, with a wing nut. Turn the nut and expand the rubber, and you have a seal. They make them pre-built, but I couldn't spot one out on the net . Probably using the wrong nomenclature.

Have a box full of the Cherne test plugs (thought we were gonna have pipe hides).

Those we've found, folks don't seem to crank the wing nut down enough, or replace 'em correctly into the pipe.

We often find 'em laying near the container.

Decided against it. Figured if some can't close an ammo can, this'd be way too complicated.

[+Bushwalker53]

I find that the best containers for underwater caches are military match containers. These are only big enough to fit a micro logbook in but they are extremely watertight and come in a variety of different colours. (Bright orange, and olive green mainly) The main problem would be trying to stop the cache from floating to the surface of the water. Good Luck!