It depends we either run on the tarry stuff the others use or we take some of the gas out of the tanks. We use some of the gas normally anyway as it boils at that temperature which means we can keep it stable while on passage with no cooling plant.

Not all LNG ships have the big round bits (breast boats to me and a few others) alot of them have nice square tanks under the deck know as the trans gaz system where as the balls are called moss rosenburgh spheres.

I can see why you have the fuse image the gas expands roughly 600 times when going from gas to liquid and them when mixed with air in the right volume for an explosion it is expanded about another 600 times. So 1 cubic metre of gas gives you 360,000 cubic metres of explosive mixture and the biggest ships carry about 140,000 cubic metres of liquid gas. So you have a potential for disastor about the same size as a medium nuclear bomb.

LNG ships where banned from american waters for about 2 months after september 11th.