1800SR3 LPG

[Argonaut]

On a previous Mercruiser powered ski boat, I had the big bonus that it had an LPG conversion, as LPG is half the cost of petrol.
At that time only disadvantage was very few places stocked it at the pump; now very easy to buy on garage forecourts, and many marinas.

So maybe a conversion is worth considering.

LPG is only 45p per litre - £2.05 per gall compared to £4.75 a gallon for petrol (UK gallon figures) to put in perspective that is equiv to $3.40 gall lpg against $7.90 gall for petrol. (US gall)


Biggest issue would be where to put tanks ... on 1800SR3 .. if I could get 2 tanks under the bow seats that would be ideal, but guess it's not likely to be possible.

Anbody any experience of converting 1800?

[tglee]

Biggest issue would be where to put tanks

I'm not an expert on alternative fuels. But, I do think that this could be a big concern.

Propane is less dense than gasoline and you must carry more of it to go the same distance. On a per unit of weight basis, liquid propane contains about five percent more energy than gasoline; however, the density is 30% less. The net result is that a gallon of propane contains about 28% less energy than a gallon of gasoline. In addition, Propane tanks can only be filled to 80 pecent of their capacity due to expansion.

I don't know what the European standard is. This comparison is based on the commercial grade of propane for automotive use known as HD-5 in North America. “HD-5” stands for Heavy Duty (propane) containing a maximum of 5% propylene (also called propene) and a maximum of 2.5% butanes and heavier hydrocarbons (also shown as C4+). This grade was developed back in the 1970's to establish a grade of propane, based on composition, that would be suitable for automotive use. That is, if the composition of propane met the HD-5 requirement, then the fuel would be suitable for automotive engines both for stability and for octane quality, without having to actually test every batch for octane or stability.

Propane with a higher butane content should yield better results.

Most automobiles are designed to run about 300 miles on a tank of gasoline regardless of their fuel efficiency (low MPG=big tank, high MPG=small tank). I'm not sure who decided this, but I guess the reason is if your in the middle of nowhere you have 300 miles to find another gas station. Anyway, you would need a large amount of propane to travel 300 miles in an average car. This is one reason why you don't see many LPG vehicles. The LPG delivery trucks are commonly LPG powered because they are carrying lots of it with them. Also, many city buses use it because they are not expected to travel far between fill ups.

I don't know how many gallons a recreation boater would burn in an hour but you would definitely need large tanks.

[Brit Rider]

Eek.. do you really think you'd get them under the bow seats? There isn't much space up there at all. Personally I'd think hard about doing it... its a big cost and you're going to need to be doing alot of hours to make it worth it.

If you really want to do it I'd cut out the kick panel in front of the drivers seat, clear the area and install a tank there then face it up with some carpeted foam board. That should give space for a decent sized tank.

[Argonaut]

Originally Posted by Brit Rider

Eek.. do you really think you'd get them under the bow seats? There isn't much space up there at all. Personally I'd think hard about doing it... its a big cost and you're going to need to be doing a lot of hours to make it worth it.

If you really want to do it I'd cut out the kick panel in front of the drivers seat, clear the area and install a tank there then face it up with some carpeted foam board. That should give space for a decent sized tank.

If I could get it done I probably would, filling up would reduce from a typical fill up price from £52 to £22
That is without fuel it the tow car !
It was great on my previous LPG boat .. but then I didn't pay for conversion, it was already done.

Now if you had a storage tank at home, you could save the road fund duty, and price drops even further .. most waterski lakes have their own tank for that reason, they get it filled with fuel tax rated as for home heating.

[tglee]

How large were the tanks on your LPG boat?

[Argonaut]

It had twin tanks ... similar to ones in this pic

http://www.iwemaenterprise.nl/Marine_installed.htm

but were not installed alongside the engine ...

If memory recalls correctly they were 2 x 70Lit tanks

[Argonaut]

Originally Posted by tglee

I'm not an expert on alternative fuels. But, I do think that this could be a big concern. .

That maybe why autogas propane has a higher energy rating that standard unleaded petrol.

Standard '4 star unleaded' is 98 RON
LPG autogas is rated as 108 RON.

Maybe that balances things out ?

[tglee]

On a per unit of weight basis, liquid propane contains about five percent more energy than gasoline; however, the density is 30% less. The net result is that a gallon of propane contains about 25-28% less energy than a gallon of gasoline.

This is North American HD-5 automotive propane. The European standard may be different. Especially if there is more butane in the mixture.