Hot Water for Diving Dredgers could be deadly,dont be that Guy
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DanfromNY
02:04:55 Wed
Nov 23 2011
Hot Water for Diving Dredgers could be deadly,dont be that Guy
Ive seen over the years many different ways to get hot water down to the diver while dredging off the coast of Nome,in the fridgid Bering Sea.Ive seen the all-in-one add ons that are home built,where water is taken away from the venturi and used for the diver.This system usually uses up some of the exhaust for the heat thru some sort of heat exchanger,most very competently built.But when they leak,its usually on the engine or the air compressor shutting one or the other off,till theyre repaired.In older heat exchangers I have heard of small pieces of gravel getting caught in the coil and forcing super heated steam down the hose to the diver.Soaking in water that will raise your body temp. is not good either. Its not reccommened for some older folks to soak in hot tubs for any length of time.This is just what happens when your wter is too hot,it actually slows you down while diving and sucks your strength out.Heres the solution that Ive found over the last few years we have been using a "on demand" hot water heater digitally controlled temperatures with propane heat and its own electric water pump to keep the flow consistent.Stay safe while diving guys,nobody needs to be overheated,later,Good gold to all, later Dan

Greg_in_BC
02:40:22 Wed
Nov 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Great tip Dan, what size heater and pump do you find you need for one diver? Is the pump on demand when the water heats or continues heating all the time?

sure appreciate you sharing all your experience from the field.

Wishing I could join you fellows up there :smile: Greg

JOE_S_INDY
18:51:17 Wed
Nov 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
I have heard (I think it was Tom Ashworth) using a Zodi brand, propane, on-demand heater for cold water diving. Temperature control is really important and the factory setup is just a good idea.

Joe

dickb
19:25:24 Wed
Nov 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Do you have problems with the propane freezing up and not vaporizing in the real cold temp's? I would worry about bringing the propane cylinders into the heated area.

Thanks in advance.

Dickb

JOE_S_INDY
19:57:48 Wed
Nov 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Hey there Dick B!

Well, propane freezes at about minus 40 or 45 degrees (farenheit or Celsius) http://en.wikipedia.org/wiki/Propane

At those temperatures it isn't something that I will ever have to worry about any more. I did see propane freeze at minus 81 degrees F. in the mid '60's - but I have managed to stay away from those temperatures since then.

Dredging in any sub zero air temperatures just seems wrong to me. Well, maybe just not something that I'll ever do.

Oh, the not bringing propane containers inside has to do with leaks. A propane leak outside is dispersed by air movement while a propane leak indoors will puddle the gas / air mixture in a low depression or area. Explosions tend to follow that. I make it a habit to never, ever have a gas leak and so never would have to worry about that.

Joe

dickb
22:15:32 Wed
Nov 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Hi Joe:

I use propane here in IA for temp heat and use 100# cylinders to feed the heater. If I tie 1 cylinder on to the heater, the withdrawal rate will freeze the tank at about 20* outdoor temp. I usually put 2 cylinders together and draw from both at once. That will usually keep the cylinders from freezing. The instant water heaters draw a lot of propane to run, but I'm not sure it they will freeze the propane tanks. Kev used oil last winter to work under the ice but during the summer months the propane wouldn't be any problem. I happen to think that the instant demand hot water heaters would be a good choice. They already have pressure and temp safety valves installed.

Dickb

JOE_S_INDY
02:28:50 Thu
Nov 24 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
And --- are made to produce a regulated temperature of water.

Whatever the system, filtered water to stop 'junk' from clogging important parts is a good idea.

Lets see, + 20 degrees air / tank temp and a heavy usage / vaporization rate inside the tank can certainly bring the liquid propane to minus 45. Then again, same situation with a mild load should be just fine. I guess if necessary, put the propane tanks in the water and warm them that way from the +32 water.

Joe



oldstyle
23:23:11 Sat
Nov 26 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
The problem with bringing propane tanks into a warm environment is that the warmth causes the propane to expand in the tank. If the tank was filled in the cold and is brought indoors, the increased temp will cause the relief valve to blow off. Filling the room with volatile vapor. Also a warning about transporting tanks laying down. If the full tank warms in the sun and the relief blows LIQuid Propane comes out the relief valve. That is the white cloud of propane that you see. Liquid expands 270:1 when released from containment. This causes the relief valve to freeze open. With a small spark things get very exciting very quickly.

MrIdaho
20:22:40 Thu
Dec 22 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
They also make electric under sink on demand water heaters that would work well for this. That is if you have a generator available. One thing that all these systems should have is a valve that the diver can adjust or turn off if the need arises.

Are you guys running hot water down into a wetsuit and letting it escape through the arms and legs, or wearing a dry suit and have heating hoses inside the suit?

Anyone diving at -30 is definitely braver than I am.

Good luck to you all.

micropedes1
23:58:34 Fri
Dec 23 2011
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Let me preface this by saying that I am definitely a cold-natured ole fart. When my hands and feet get numb, I am definitely thru dredging, whether I am getting good gold or not.

I use an exhaust-heated hot water system. I have used it with a wetsuit for several decades. And have been successful by taking screening precautions and using a tempering tank. But Alaska conditions dictate some refinements that were not necessary in the lower 48. Up north, I tend to favor a drysuit, gloves with a ring system, and insulated Muck boots. Not better than the wetsuit, just more flexible and comfortable in the cold water. In the last season or so, I have modified my setup to include a "coolshirt" under my drysuit. The manufacturer assured me that using their product to keep warm in frigid waters was not what it was designed for, but it would not leak warm water into my drysuit. (made to cool off athletes). Kinda pricy,for a shirt. But it works flawlessly when tied to my existing hot water system. And allows me to stay in very cold water far longer than I would without the added warmth. Not trying to sell their product. Its just another alternative to consider. Oh, the "coolshirt" is worn over thermals and not next to the skin making the possibility of a hot water burn extremely unlikely.

http://www.coolshirt.net/acc-cool-shirt-options.html


DanfromNY
19:14:13 Sun
Jan 8 2012
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Hi All, I dont preheat my propane tanks,I do try to leave them in the sun away from where I store my gas. I wear the under armor brand cold gear under my wet suit and I have for a number of years. The shirt and pants both run about $50 a pair, but being skin tight really hold the heat into my body with the hot water added to the body of my suit less frequently then its in my gloves or head gear.Its my hands that get cold when the suction sucks the hot water out and draws the cold water in from the other side of the glove.Ive used a drysuit, but theres just too much sharp stuff under the water up there,Im repairing my wetsuits regularly.I will be trying an electric on demand system this season. I remain optimistic,it should use less power with diver shut offs installed. Good luck to All, Dan

DanfromNY
16:10:41 Fri
Jan 27 2012
Re: Hot Water for Diving Dredgers could be deadly,dont be that Guy
Heres a video showing what it was like before hot water, and you really need heat in hands down there.
http://www.youtube.com/watch?v=t2yRlEowTOY&list=UUFn3aIJ3MOIXn3pfwUVfGwQ&index=30&feature=plcp



Hot Water for Diving Dredgers could be deadly,dont be that Guy
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