Deco Habitat Design

[apitkin]

Mike Poucher summarized what we've been doing very eloquently.

Here is a French page on deco habitats:
http://www.plongeesout.com/articles%...gruissanot.htm

And the Google translation:
http://translate.google.com/translat...520douchet.htm

This has a lot more information about securing the habitat if you don't have a roof to put it under. When you calculate the forces involved, you realize you have to take the tie-down system very seriously.

Andy

[Dive Africa]

Here is a pic of KUR's small Habitat that is installed in Madison Blue

Thanks Billy - I managed to source two of these - for free (Thanks Steven) We'll start playing with these and once we have patted the technique down, we'lll try something bigger - I found a very nice 2250l horizontal water tank (about $700) that would be perfect.

Natuarally just propping the habitat up against the roof is 1st price, but I think it is not going to be possible (will look for a spot - but the entrance to the cave might be to deep.

The open hole is between 35m and 50 deep so the bottom might not work (also a lot of silt) - we might be able to drill into the shear cliff sides and attach anchor bolts, We will also look for big boulders.

Any advise on what tyype of ropes cables, chains, attachment points, etc that we can use.

Also any other tips, warnings on handling the crates in open water?

Regards Dries

[FW]

...The open hole is between 35m and 50 deep so the bottom might not work (also a lot of silt) - we might be able to drill into the shear cliff sides and attach anchor bolts, We will also look for big boulders.

Any advise on what tyype of ropes cables, chains, attachment points, etc that we can use.

Also any other tips, warnings on handling the crates in open water?

Regards Dries

One problem attaching it to a wall would be uneven tension on the hold down lines. You may have to reinforce the sides of the habitat so it won't collapse from the uneven loading.

Be really sure it is secure, because if it comes loose on deco, whoever is in it will get a very fast ride to the surface.. It it hits another diver on the way up, they will be hurt as well.

[OFG-1]

If you are in that deep of water,I suggest a open bell with a winch and anchor, you can winch it down to depth, then let it come up as you do.

These used to be lying around the Gulf used a few years ago, I dont know if any are still around. This is good for a picture, but the price is crazy. If you weld, these aren't hard to make.

http://www.ebay.com/itm/NAUTILIS-2-M...item4aaca12dcf

[chilldive]

Also any other tips, warnings on handling the crates in open water?

Once you get things in place all will "look" good, then you start filling with air and things can unravel in a hurry. Lots of uncertainty when you start filling so be careful and make sure everyone is out of the way and paying attention.

[mpoucher]

Any advise on what type of ropes cables, chains, attachment points, etc that we can use.

Also any other tips, warnings on handling the crates in open water?

If you plan to anchor one to the floor, I would go with good tubular webbing, or chains for strength. A come along system, or the cam bands for tying down loads should work for making it adjustable. I think you may have to reinforce the cage to take the strain. The crate was pretty easy to handle in the water. It floated nicely on top while we got in and attached a lift bag, and then turned it over to make it sink. The plastic pallet took a little while to fill with water - I would drill a few more holes to make it fill quicker next time around. We were able to swim it in relativily easy with no flow in Alachua, but in Madison, with the flow (and the flow was not high by any means!) it was more of a challenge. We swam it in part way, but as the passage got lower, we didn't have clearance for the lift bag, sowe ended up rolling it along the floor to get it in place (all sand and rubble).

[huxley]

It might be wise to use spreader bars, or a platform or a simple steel cross a few feet below the cage to allow to chain the cage to it in all corners straight down. from there on you can go to a single point of attachment in the center down to the anchor. This will avoid the cage from deforming at the rim since you don't have any horizontal forces. If you run any of the chains that attach to the cage in an angle you will need to reinforce around the rim. It might come in handy as a platform to stand on as well.

[apitkin]

Thanks Billy - I managed to source two of these - for free (Thanks Steven) We'll start playing with these and once we have patted the technique down, we'lll try something bigger - I found a very nice 2250l horizontal water tank (about $700) that would be perfect.

Natuarally just propping the habitat up against the roof is 1st price, but I think it is not going to be possible (will look for a spot - but the entrance to the cave might be to deep.

The open hole is between 35m and 50 deep so the bottom might not work (also a lot of silt) - we might be able to drill into the shear cliff sides and attach anchor bolts, We will also look for big boulders.

Any advise on what tyype of ropes cables, chains, attachment points, etc that we can use.

Also any other tips, warnings on handling the crates in open water?

Regards Dries

And lastly, don't forget to take pictures and write up your experience so we can learn from it too!

Good luck.

[FW]

It might be wise to use spreader bars, or a platform or a simple steel cross a few feet below the cage to allow to chain the cage to it in all corners straight down. from there on you can go to a single point of attachment in the center down to the anchor. This will avoid the cage from deforming at the rim since you don't have any horizontal forces. If you run any of the chains that attach to the cage in an angle you will need to reinforce around the rim. It might come in handy as a platform to stand on as well.

But what if they have to attach it to the wall?

[huxley]

I would attach the platform with 4 individual chains to the wall, lets say 30' below the platform with individual length chains so the platform would be leveled. Picture mountaineering if they hang a platform off a cliff on a single anchor point in the wall, now turn this picture around and you have the floating platform. My biggest concern would be to pull one of the boulders out of the side wall of the quarry. keep in mind you are applying a couple 1000's pound of force, that might loosen something up and now what, you either go up or that whole thing goes down if the boulder is big enough that you are attached to. It depends on the local conditions but sounds like it is safer to look for the big on on the ground and use it as a counter weight, its not going anywhere neither down or up unless it is too small.
If chain wraps around the rock are done right so that they can only tighten up ( lets say couple loops at the corners of the rock that get combined to a single attachment point for the up chain) this should be foul proof. Just keep in mind the rock might move a little while you fill up the habitat.
Second bet would be drill holes and use expansion bolts, but make sure you have plenty, while the bolt might hold couple thousand pounds the rock might not.