How to fill my CNG tank in my '89 C-30

[daave]

Have 1989 Catalina 30 recently inherited with CNG tank for the stove/oven.
Pls help with details on fillling the CNG tank. Stove/Oven Manual says fill to half so as not to blow fittings. The manager of the CNG automobile filling station says their pumps fill to 3600 psi and he's not certain the tank for the boat can take that pressure.

Are the fittings for filling a car at the CNG station the same for the fittings on the tank?

What is the capacity of the tank so I can know what "half full" is? Tank looks to be 5 gals.

Many tanks,

daave

 

[Stu Jackson]

CNG refill

There is, or should be, a regulator on your boat connected to the hose that goes to the stove, and the connection (reverse hand thread) to the tank. The regulator controls the outgoing pressure. Our setup includes a pressure gauge on the regulator which shows the remaining fuel left in the tank, by pressure. Our gauge goes up to 3500 psi. The tanks we get are usually 2000 to 2500 psi when new (newly refilled - we swap empty tanks for full ones for $20).

The refill fittings have to be the same because the tanks only have one connection. If they're different, adapters should be available.

There was a post just this week on CNG with some good references. Look it up and read it.

Our CNG tanks are really heavy, look like oxygen tanks in a hospital, but are painted white. There is no way one could estimate it are being 5# as you've guessed - don't know how you got there.

If it was me, I'd ask him to fill it up to 2500#, take it to your boat, assure you have the right fittings, make sure the regulator and gauge and hoses are fine, connect it and light the stove.

After your read the suggested info, and check out the safgas website so you're sure you've got CNG. Reason I say this is all sounds a little fishy to me...

 

[daave]

Re: CNG refill

Thanks alot, Stu. I'll check the safgas website. I did a search in the archives for CNG and came up with 72 pages. Gave up after reading 15 pages since nothing related to the CNG refill. Our boat has the fittings and gauge. Since I've never refilled a CNG tank, I'm not familiar with whether the psi on refill can be regulated. According to the manager of the CNG sales in California, they pump only 3600 psi. I guessed at 5 gals based on the size in comparison to the LPG tanks we use on bar b ques, rvs and marine apps. The manual says fill the tank to half full. Strange instructions if you ask me. But then, what do I know.

Cheers, mate

 

[Stu Jackson]

CNG tanks

I understand. As long as the tanks look like WWII torpedoes, you're looking at the right thing. Anything else, lt me know, because CNG requires those blasphemous tanks.

Here's the link to that other discussion: http://forums.catalina.sailboatowners.com/showthread.php?t=109634

I understand you searched for CNG, I was just suggesting going back to read the past few days of discussion to find a topic with CNG in the heading. Sorry about that, I should have given you the link right away.

You may also be interested in this: http://c34.org/bbs/index.php/topic,4938.0.html Feel free to do a search there on CNG, more reading, I know, but there search engine also gives you some gist of the discussion to see if it's worth reading. A lot of our guys and ladies have had the same issue, as you can imagine.

For instance, the third one down on a search on the C34 MB is "CNG-Pressure" here: http://c34.org/bbs/index.php/topic,4439.0.html