Gas pipework on houseboats

Does anybody know anything about installing natural gas pipework on a static houseboat? I have been told that only compression fittings can be used for copper gas pipework? This doesn't sound right to me, but then I've never fitted NG on a houseboat.... Does this mean that all gas pipework must be surface mounted? Is this guy pulling my leg?

if you take your boat out of the water, and connect a pipe that is connected to the national distribution system, then you can have natural gas,otherwise you can use lpg(bottled gas)iam not 100 percent but i think you have to hard solder/braze all pipework on boats, this is not a diy job,i strongly advise you to get someone who is experienced with gas installations on boats

Have a look at this, the answer is here, this is a GOOD site, you will have to dig it out http://www.canalworld.net/forums/index.php?act=idx