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Old 09-07-2016, 06:11 PM   #41
tinped
Senior Member
 
Join Date: Dec 2007
Posts: 380
Quote:
Originally Posted by Comodave View Post
Gas vapors do indeed drop because they are heavier than air. Air has a weight density of 1 and gas vapors have a weight density of between 3 and 4. Vapor densities less than 1 will rise and greater than 1 will fall. The problem with carrying gas on board a diesel powered boat is that if there is any small gas spill or leak, the vapors can travel down into the boat causing a potential explosive situation. Vapors can travel a lot farther than one might think. Most diesel powered boats do not have ignition protected components installed in them because they are generally not required on a diesel boat. Most diesel powered boats do not have ignition protected bilge blowers either so if you do get some gas vapors down into the bilge, how do you get them out without blowing up the boat? When we carry gas for the dinghy, we either leave it in the dinghy on the swim platform brackets or strap it down on the swim platform. That way if any vapors get out of the tank, they will drop down to the surface of the water and dissipate without any problem. If you do carry gas inside the boat or up on deck/flybridge you should look at the potential paths that the vapors could take into the boat. If there are paths that lead into the boat, find another place to store the gas.
Really interesting catch.I wonder why abyc,or ul,or some other governing agencies haven't caught onto that.Since the vapors will settle lower,where the diesels are,and if given the opportunity to get below deck(open hatch or such),and there are no ignition protection devices to be found,doesnt that present itself as a possibility of an explosion?It is common place for those with dinghies to carry gas.Surprised that they are not requiring some sort of a vaportight,or explosion proof enclosure.
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