It's not very pressurised. The 95 litre tank in my old Range Rover is around 8 bar, which is about half the pressure in the air suspension tank and only about three times the pressure in the tyres. Although as you say being able to just pour more petrol in from a can is an advantage!
CNG and hydrogen tanks need ridiculously high pressures - 250-300 for CNG and over 700 bar for hydrogen. Even if that was dry nitrogen it would be a potentially lethal bomb!
The nice thing about LPG is you can use plastic pipe and inexpensive compression fittings that are easy to connect and disconnect when you need to work on stuff. If you undo a pipe and it's got line pressure in it, the biggest problem is that it stinks and you might get frostbite if it sprays on your hand. It just kind of hisses out a bit. You want to do this outside though if you're unsure if there's pressure there.
Propane is a lot less explodey than petrol, so you end up using a little more of it but you get a bigger slower bang, which gives you less flat-out power and more torque. Everyone needs more torque, no-one needs to be flat out wide open throttle. The downside is that being less explodey, it means you need the ignition system to be in perfect condition. I get about 10,000 miles from a set of spark plugs before it starts getting hard to start and noticeably groggy acceleration, even allowing for it weighing over two tonnes and and having a 200bhp engine. It's never going to be fast! At least it's lawnmower-grade spark plugs, good old BPR6ES, same as in your boat engine.
CNG and hydrogen tanks need ridiculously high pressures - 250-300 for CNG and over 700 bar for hydrogen. Even if that was dry nitrogen it would be a potentially lethal bomb!
The nice thing about LPG is you can use plastic pipe and inexpensive compression fittings that are easy to connect and disconnect when you need to work on stuff. If you undo a pipe and it's got line pressure in it, the biggest problem is that it stinks and you might get frostbite if it sprays on your hand. It just kind of hisses out a bit. You want to do this outside though if you're unsure if there's pressure there.
Propane is a lot less explodey than petrol, so you end up using a little more of it but you get a bigger slower bang, which gives you less flat-out power and more torque. Everyone needs more torque, no-one needs to be flat out wide open throttle. The downside is that being less explodey, it means you need the ignition system to be in perfect condition. I get about 10,000 miles from a set of spark plugs before it starts getting hard to start and noticeably groggy acceleration, even allowing for it weighing over two tonnes and and having a 200bhp engine. It's never going to be fast! At least it's lawnmower-grade spark plugs, good old BPR6ES, same as in your boat engine.