The Commercial Diver Network
Hello everyone! I have several questions.
I’m working on a novel that takes place during a deep dive. I’ve done a lot of research so far so I’m not coming in here blind and I have been SCUBA diving for a fair amount of time.
For some background information my fictional divers are diving with twisted umbilicals that have gas / headlamp / comms / and hot water connected to them.
1: Where do each of these lines connect to the diver? Surely the hot water doesn’t go into the helmet does it?
does the gas line go into the spare air tanks on the back? How do those tanks work (a reference guide site would be amazing). From what I see they look like rectangles of some kind. It’s very confusing.
2: What are those hot water suits made of? Is it a wetsuit or dry suit filled with warm water?
3: How heavy are these suits/helmet? Is it completely impossible to swim?
4: What keeps the suit’s water from entering the helmet? A series of collars?
5: Is the umbilical attached to a harness on ALL dives?
Any help with these would be GREATLY appreciated, as a lot of the institutes I’ve asked have ignored my inquiries.
I’m sure I’ll have more questions in the months to follow.
1) A dive umbilical is made up of the following:
Main air / gas
Communication (comm line)
Pneumofathometer (pneumo hose - used to measure Diver's depth and can be used as emergency air / gas supply
Other members can be added such as hot water, video, and light cable.
If the umbilical is not twisted, a strength member, usually 3/8" rope will be added.
The umbilical is always attached to a harness. This prevents strains from being applied to the hose connections. The main air / gas hose and bailout bottle hose connect to a side block on the Diver's helmet. This allows the Diver to operate the air trane to flush the helmet and turn on the bailout bottle. One of the most important fittings on the side block is the one way valve which is where the main air / gas hose connected. The comm line connects to posts or a marsh marine fitting on the helmet.
Hotwater suits are made of neoprene. The hotwater hose connects to the hotwater suit. For safety reasons this connection is always a quick connect fitting.
What keeps water from entering the Diver's helmet (hat) is the neck dam. This has a neoprene or latex seal that fits on the Diver's neck and then has a ring that connects to the helmet. This also keeps the helmet (hat) from floating up and off the Diver's head. Helmets do leak some from time to time.
There are many different styles of helmets, but the weight in air is approximately 28 - 30 lbs. When underwater, the helmets are usually a couple of pounds negative. You can swim, but without fins and dragging the umbilical behind you, it is a little difficult.
The Diver wears a bailout bottle on his back. This is for emergency air / gas backup. The bottle is usually 30 cu. ft. to 50 cu. ft. The picture you saw may have been a couple of smaller bottles that were housed in a protective housing.
Hope this helps.