LPG RIBs

Colin F · 01 August 2003, 21:59

Anyone heard of LPG powered ribs anywhere? I'm still considering which is the best value for money/ value per hp solution to powering a 7m rib, which I'm soon to buy. Lots of choice for mercruisers, and they can apparently all be converted to LPG which is available at a fair few marinas on the south coast, and around most of the uk. Marine Gas sells for about 32p per litre - and you get the performance of a petrol engine. This sounds too good to be true!! Conversion costs are around 2000 - 2500.

Any experiences out there?

I run a mitsubishi L200 3 litre on LPG which works brilliantly.

Hope someone can advise.

Ribnwheels

Richard B · 01 August 2003, 23:35

No direct experience, but heard a few tales...

Hamble harbourmaster converted a couple of Honda outboard powered Cheetah Catamaran hulled workboats - than converted them back after problems (allegedly).

Look on ybw.com forums (motor boat chat) and do a search on LPG. It throws up some interesting stories, and some horrors!

As far as I know, if you powered a RIB on LPG, you'd be at the bleeding edge of marine technology.

Alan · 02 August 2003, 08:49

I did some research into this a couple of years ago, including whether there were any LPG conversions available for 4 stroke outboards. I was advised at the time that there were but since they were low volume production from CNC machined kits they were expensive but volume production was coming. Well to the best of my knowledge this hasn't happened yet!

The other thing that reall killed it for me was tank location - needs to be vented to the air / overboard which I think would make underdeck tanks probelmatic and whether the tank would stand up to the pounding that a RIB takes.

Having decided it was a non starter I then went on to look at Diesel (numerous threads about petrol vs diesel on rib.net if you search) but decided that purchase costs for what I wanted were out of my reach. Only option then is for hitech 2 or 4 stroke outboards and accepting that 1l per mile (approx) consumption at 80p litre is the price to pay for being a petrolhead!

Chris Murray · 02 August 2003, 10:23

I heard the same story about the Hamble Harbourmaster's boats.

I shouldn't worry about being a "petrol-head", I doubt that there will be quite the same enthusiasm for diesel engines, when the fuel costs are similar to petrol (2006?). Have you compared the weight of a 300hp diesel to the new Yam 300 HPDI?

I appreciate that diesel is more readily available on the water in the UK/Europe, but try convincing US boaters that diesel is the way to go!

Just a thought ...

Chris.

Mike C · 03 August 2003, 12:52

I believe Ribcraft are planning an LPG boat. Whether they've actually built one yet or not I don't know but worth asking www.ribcraft.co.uk

Personally though, I would still be worried about having a pressurised fuel tank on board a RIB! Probably ways to solve all problems but while we can buy red diesel at 30p or less, I don't think they will take off. Maybe if/when that concession goes it may be different......

I think you can convert a diesel engine to LPG can't you? Not much point now - something to worry about in the future!

Mike C

Chris Murray · 03 August 2003, 20:05

Oh no you can't !!!

LPG requires spark plugs, so conversion from diesel would be a bit of a problem. Quite a large problem actually !!!

Incidentally, I understand that LPG engines are usually best started on petrol, before switching to LPG. I am not really sure why, but I think it might be to do with valve lubrication. This may not apply to an LPG car, as they tend not to get "thrashed" every time they are run.

I looked into LPG for my last boat, which had a 5.7litre V8. One of my biggest concerns was that no-one at that time could supply a satisfactory stainless tank. The idea of a painted MILD STEEL tank in a salt water environment did not impress me very much.

I also felt that the marine LPG industry (there were 2 suppliers at that time) really hadn't got its act together and was probably best avoided. Things may be better now though.

BTW, LPG is less efficient than petrol but is a bit lighter.

Chris.

Mike C · 03 August 2003, 23:16

Quote:

Originally posted by Chris Murray
Oh no you can't !!!

LPG requires spark plugs, so conversion from diesel would be a bit of a problem. Quite a large problem actually !!!

Thanks for that Chris. Someone told me I could convert my diesel CAR to LPG once, (Salesman I think). I didn't think it sounded very likely at the time!

I've no intention of even thinking about doing it to my boat. I currently use half the quantity of diesel compared to the amount of petrol I used on my old boat..... so even if the tax goes on diesel, I’ll still be paying half the price I used to pay!

Mike C