CNG Blues
Our 1991 Legend 37.5 came with CNG and a single tank. Soon we realized the difficulty in filling our CNG tank, even in a boating Mecca like the greater Detroit area. Here is how we solved our CNG problems. First, you probably need a second tank and a place to store the tank on board. Tanks are available from various on line merchants for about $100 or so. Next, you need a way to fill the tank. Most metropolitan areas have CNG filling stations for natural gas automobiles. These are listed in the phone book. You will find that the fitting on the CNG tank and the fitting on the CNG fill nozzle are not compatible. There is a piece of hardware (we call it a "phramus") that will bridge this gap. I do not know where you can buy a phramus, but there are some good instructions on how to make one on this web site. It does not look too difficult to assemble, once you obtain all of the parts. You need to EXERCISE EXTREME CARE in filling your tank. The pressure from the filling tank exceeds the allowable pressure in the CNG tanks. So just add a little cng at a time, i.e. less than 1 seconds worth, and then check the tank pressure. Do not exceed the rated capacity for your CNG tank. There was a company that sold us our phramus last year. A couple of months after we bought it we received a registered letter saying do not use the phramus. Apparently, some one was filling a CNG tank using their phramus and the tank exploded causing serious unjury - I think they exceeded the allowable pressure. The company promised us a safe-replacement phramus, but I guess they lost our address. I realize there is some risk in filling the tanks this way, but we have been very careful and have not had any problems. There is no viable alternative other than an expensive conversion to propane.
