daniel f aleman:
Plenty of cave and technical divers use a "conventional" BC. Such a BC isn't my preference for any diving but why wouldn't you take a diver into a cave without a backplate?
BP/W are banned! And other fun things I've learned on my first chartered dive ...
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Plenty of cave and technical divers use a "conventional" BC. Such a BC isn't my preference for any diving but why wouldn't you take a diver into a cave without a backplate?
We used horse collar BC in the 70 in caves with great success. In particular the dual bladder Dacor. I don't think a cave dive needs a BP, there could be other suitable equipment.
I am sure 80 MPH is way more than would be needed to clear the water. After all, a dolphin swims at 15 to maybe 30 MPH and they clear the water. No scuba diver will ever swim 20 MPH much less 80 with or without an 80 lb lift BC. Is there even such a thing? I have seen 60 lb lift but 80? I guess there could be such a thing. N
I am sure 80 MPH is way more than would be needed to clear the water. After all, a dolphin swims at 15 to maybe 30 MPH and they clear the water. No scuba diver will ever swim 20 MPH much less 80 with or without an 80 lb lift BC. Is there even such a thing? I have seen 60 lb lift but 80? I guess there could be such a thing. N
OMS makes a Dual 94#, scary.
daniel f aleman
Contributor
Mike,
All divers act as a team and use the same equipment set-up while on a particular cave dive. If a group of divers all want to dive in a cave wearing the same BC, fine.
All divers act as a team and use the same equipment set-up while on a particular cave dive. If a group of divers all want to dive in a cave wearing the same BC, fine.
abitton
Contributor
daniel f aleman:
This is what DIR divers do (not necessarily a bad approach, mind you), but somehow I don't think this is a hard and fast rule...
And I would think that if you take divers in a cave, and they're all tourists (albeit cave-trained), you expect that there may be significant variations in their configuration... Unless you specifically say that your customers must have equipment X, set up in configuration Y when you book the dives...
abitton
Contributor
Nemrod:
As Eric said, this is a job for the Mythbusters!!!
Here you boys (and girls) go:
Begin Qoute (pants!)
There are a couple of components to this. The first is the amount of thrust able to be generated by the fins while kicking. Your example, a stuck inflator valve, assumes the dude was not kicking hard straight up so it can be discounted.
Once the guy leaves the surface of the water, there is no more force acting on him except gravity. If we assume that the downward force of the weight of the human + gear that are currently out of the water balances with the buoyant force of the inflated drysuit below the water equalizes when he is about chest-deep, then the diver has an additional 5 or 6 feet to rise before his fins clear the water's surface.
Neglecting additional water drag while the fins are being lifted out of the water, any negligible lift created by the legs of the drysuit, and a host of other things, the diver will need to clear the surface of the water at more than 12 mph, or 17 feet per second.
I can't believe I actually typed all of this out. The whole idea is one of the dumbest things I've ever heard.
You'd have better luck making a bus jump a 120' long gap in a bridge like you saw in Speed. Oh, wait... you thought that was really possible, didn't you?
End Qoute
Begin Qoute (pants!)
There are a couple of components to this. The first is the amount of thrust able to be generated by the fins while kicking. Your example, a stuck inflator valve, assumes the dude was not kicking hard straight up so it can be discounted.
Once the guy leaves the surface of the water, there is no more force acting on him except gravity. If we assume that the downward force of the weight of the human + gear that are currently out of the water balances with the buoyant force of the inflated drysuit below the water equalizes when he is about chest-deep, then the diver has an additional 5 or 6 feet to rise before his fins clear the water's surface.
Neglecting additional water drag while the fins are being lifted out of the water, any negligible lift created by the legs of the drysuit, and a host of other things, the diver will need to clear the surface of the water at more than 12 mph, or 17 feet per second.
I can't believe I actually typed all of this out. The whole idea is one of the dumbest things I've ever heard.
You'd have better luck making a bus jump a 120' long gap in a bridge like you saw in Speed. Oh, wait... you thought that was really possible, didn't you?
End Qoute
KansaiKitsune
Contributor
Nemrod:
Could you introduce me to this 20 year old bimbo PADI dm? I could use some one on one training.
KansaiKitsune:Could you introduce me to this 20 year old bimbo PADI dm? I could use some one on one training.
If she doesn't realize the value of a harness, a crotch strap and some well placed d-rings I wouldn't even bother.
opalobsidian
Contributor
Cave Diver:If she doesn't realize the value of a harness, a crotch strap and some well placed d-rings I wouldn't even bother.
OH!!!!
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