LPG as an a primary source of fuel

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BlueSkyNick

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filling the car with diesel today, looked across the forecourt to the LPG pump totally unused, despite the much lower price. With the apparent shortage of gas in the North Sea, this might change, but nonetheless I stood there wondering why there has been little take up.

I know there is a cost to installing the conversion kit and the tank, which itself takes up a significant chunk of the boot space, but for a high mileage commuter or business man, it would seem economical.

Then thought about using LPG in a boat especially after red diesel is unavailable.

Safety is obviously top of the list, but if it can be installed in a car, it should be OK? After all, cars are far more likely to have an accident, at much higher speed, and cause a lot more damage if the gas tank blows, than would be the case in a boat.

So what are the REAL issues?
 
I'd certainly consider it in a car, as it's been tried and tested, and good availability of fuel in most areas.

However, all the boat conversions I've known have had problems, and the number of marine lpg outlets has dropped, meaning in many areas it is impossible to refuel
 
LPG conversions are for petrol engines only, if you now have a diesel you would have to change the engine. There is a small power loss on conversion. I would regard an LPG engine on a boat as being just as dangerous as petrol. Problem is that just like petrol vapour, LPG is heavier than air, so any leakage would collect in bilges, and, again like petrol vapour it makes an explosive mixture with air. Despite cost (diesel is about £1 per litre in Turkey), I regard it as the appropriate fuel for a yacht auxiliary engine, or powerboat.
 
My petrol car was succsesfully converted and the savings have been great.
If my boat was petrol I would certainly consider the change.
Contrary to one view I dont think that a diesel can run (totally)on LPG, it can run on a mix of diesel/lpg (as it can on diesel/petrol) but I dont think that this is really to be reccomended!!
 
I think the safety issue of the danger of LPG leakage is the decider for me - although I do have LPG cooking and water heating. I would stick to diesel for motion!
 
As an aside, my central heating boiler runs on gas oil which is shared with my domestic standby generator (diesel).

Although I am sure this price has changed, I last paid 33p (including 5% VAT) per litre for this.

Is there any difference between gas oil and red diesel and, if not, why can I not use this in my boat engine (while the concession lasts)?
 
If I had a petrol engined boat I would save my pocket money for putting in diesel/s rather than converting to LPG, and I say so after three years of driving a Bi-fuel car very happily.
There are several reasons the most significant being the small number of LPG outlets anywhere accessible by boat. This is less of a problem for owners who trail their craft; they can pull into any forecourt to fill up. Going on my experience as a car LPG user the number of outlets will not increase. For road use they have been closing down, one consequence of supermarkets closing filling stations with their competitive pricing. I haven't seen a single supermarket with LPG while calor shops don't accept most auto-cards and are shut when you need them.
Back to boats.
LPG needs petrol for initial ignition. This means you will need a petrol as well as an LPG tank with associated switchover gear. This complication in a marine environment is not welcome.
The number of running hours on LPG per litre will be slightly less than for petrol and a lot less than diesel. That means an LPG tank will need to be about a third bigger than diesel to give the same endurance. As its a pressurised tank it will need to be heavier than a simple container.
The last factor is safety which others have dealt with, although I did see a fishing boat in Cyprus which had a four stroke outboard with a pipe leading to a domestic butane bottle in the bilge.
I walked away rather smartly.
 
a very informative response Gordon, thanks to you and all the others too.

whilst my query about LPG on boats was purely rhetorical, i have been thinking about buying a bi-fuel car. Your comments on reducing availability are a concern - presumably you either have to drive out of your way to a known LPG outlet or risk burning more petrol than desired, if you can't find one.
 
Re cars I think the problem is that most have to be converted & the sums aren't attractive.
Av 12000 miles/year @ 30 mpg petrol car uses about £1630 fuel. On LPG @ 24 mpg it's about £930 saving around £700/year. So payback is around 2 years. 2 years where you've saved nothing & mebbe want to change the car by then.
Also chance your exhaust valves have burnt out by then.
 
Chas, I agree safety at sea must be the prime concern no point in trying to save a few pounds and then blowing yourself and probably others up. Diesel should in my view be the fuel of choice by the yachtsman. Removing the tax concession on diesel is like saying we should all wear seat belts as its safer, but guess what, we are putting a 100% tax on them.
We actually had a prospective member a few years back who wanted to run a pipe from a gas tank in the yard to his boat on the jetty about 50 yds away. Fortunately diesel is fairly idiot proof, gallon can, funnel and just pour it in.
 
Valve wear will only be a limited factor if you are wide open throttle everywhere. Normal use will only degrade valve life by a limited amount on a modern engine, if at all.
 
Interesting online quotes...

You may have seen it, but there's an interesting online quotation system on the Greenfuel website. Input your car details and annual mileage, and it gives detailed conversion cost and full breakdown of fuel savings. Also gives details of nearest LPG stations.
 
Spot on! I think my point is that I feel I know, and can cope with, the dangers of LPG powered cookers, whereas the thought of having an LPG fuelled carb/injection system on my engine, with the attendant risks of leaks or fractures would be too much.
 
Have any of you had first hand experience with marine gas converted petrol engines?

If so I would be interested in your opinions, if not then most of you will be of the opinion that a gas installation makes a petrol engined boat more dangerous.

This of course is not true, infact the opposite is true, a gas converted boat has more safety systems than one without.

The gas detectors will not allow the engine to be started this includes if they have a sniff of petrol.

Of course petrol/gas will always be more volatile than diesel but when treated accordingly then why should it be a problem?

Now, most that have a diesel engine will be likely carrying a 5 litre tank of unleaded for the tender outboard & LPG for cooking facilities, just because you have diesel as a primary fuel dousn't make a boat immune to petrol related dissasters, assuming the above is true.

When you know the dangers then you are more vigilant.

Look at the ratio of petrol powered craft to that of diesel, contrary to what some believe they don't blowup quite as often as some would like you to think.

I know 3 people who have gas converted thier petrol craft, all are extremly happy with the outcome.
In one case the conversion was done 4 years ago, all have reported no more problems than can be expected after years of average use.

The savings are twofold, first the boats are cheaper to buy even including conversion you save on the initial purchase price.
Second you save on fuel costs which is why most diesel engine buyers choose diesel in the first place & of course availability.

This begs the question if Gas converted boats are as cheap to run as current diesel powered craft & gas becomes as readily available then how many will hang onto thier thirsty diesels when the price per litre rockets to £1.20 a litre?

I for one will be interested in the resurection of gas as a primary fuel & will consider a petrol with gas conversion if the diesel price hitts the same level as current petrol prices.

How many others have thought the same? or will the thought of petrol/gas be too much for some? /forums/images/graemlins/confused.gif
 
I recently changed an LPG powered Transit for a new Diesel one. The previous van was a few years old and not particularly economical and I calculated the extra mpg of the diesel would cancel out as near as damn it the saving on the price of LPG. I guess the new factory equiped vans may be a bit more economical but my major bug bear was having to fill up twice as often even though I had a fairly large (by car standards) tank fitted.
One thing to consider if converting a boat is carrying extra fuel. Refilling an LPG tank is near impossible unless you get a transfer pump.
One thing I do miss is clean engine oil, even when it was due for a change. That and never even coming close to emission limits at MOT time.
 
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