Converting outboards to autogas!!! - Page 2

chewy · 03 April 2009, 06:47

We'll see what happens.
MBM keep going back to the Doctor who's baot Causation is converted to gas. I think he liked it but was running decent size engines. He had problems like everyone else.
Are Hamble still running gas on the Hondas?

Turbodiesel · 03 April 2009, 23:00

Its not hard to convert an outboard to run on gas, we have been playing with LPG outboards for a long time. It has to be a 4 stroke though!. We have just finished a Mariner 60hp EFi running on LPG and a 20hp. The biggest problem is the rules and regs about having lpg tanks in a boat its a total nightmare!!. Its also very hard getting all the lpg stuff under the cowling!.
The LPG tank must be vented from the bottom of its locker over board, so on a rib its very hard, the gas must "fall" so the outlet must run down hill and vent outside the boat. So unless you have gas tank sat in your rib at waste high its pretty hard to do. The LPG must vent above the fully laden water line on the boat too. You cant use a blower either by the way!. We think we have cracked it and are currently having a 4.8m Ribcraft built as a demo boat which we are hoping to have in the water a the Seawork show in June if anyone wants a ride!. We looked at putting the lpg on the deck and venting it through the bottom of the transom but the tanks are pretty large and take up to much room in the boat, also the weight of the tank sat at the back of a small rib causes problems with weight. There are rules about having the tank inspected so the tank must be accessable, so you cant have it mounted under the floor ( this would also stop you venting it as the gas must fall to the outside of the boat) LPG being heavier than air. You must also have expensive gas lines made up. You cant run LPG fuel lines under the deck as you can see them if they have a leak. Its all very hard work!!. This is just a small part of the nightmare rules and regs which is why no one makes an LPG outboard. Mercury bought out a small range of engines but dropped them as it was to hard to comply to the regs. The regulations are all set by code of practice 18 set by the Britsh Marine Federation, Recreational Craft Directive if you have insomnia and fancy a read!!

chewy · 04 April 2009, 07:53

Still thinking of doing it?

codprawn · 04 April 2009, 20:14

What about using hydrogen? Great for the environment - not much harder to handle than LPG and so light it will just rise up out of the boat so much safer as well.

Chris · 05 April 2009, 19:47

Quote:

Originally Posted by codprawn

What about using hydrogen? Great for the environment - not much harder to handle than LPG and so light it will just rise up out of the boat so much safer as well.

And its readily available at every marina

Nos4r2 · 05 April 2009, 20:01

Quote:

Originally Posted by codprawn

What about using hydrogen? Great for the environment - not much harder to handle than LPG and so light it will just rise up out of the boat so much safer as well.

There's a problem using hydrogen. It can't be compressed enough to make it viable to carry enough for fuel.

codprawn · 05 April 2009, 20:31

Quote:

Originally Posted by Nos4r2

There's a problem using hydrogen. It can't be compressed enough to make it viable to carry enough for fuel.

Liquid hydrogen is. There have been a few cars using it - BP even had some petrol stations dispensing it in London before Red Ken killed it!!!

And I am not on about some silly hybrid or fuuel cell - just stick it in your V8 and go!!!

Poly · 05 April 2009, 21:00

Quote:

Originally Posted by codprawn

Liquid hydrogen is. There have been a few cars using it - BP even had some petrol stations dispensing it in London before Red Ken killed it!!!

And I am not on about some silly hybrid or fuuel cell - just stick it in your V8 and go!!!

The energy density (i.e. number of Joules you can get from 1L of stored material) of liquid hydrogen is less than a third of petrol. And thats before you take into account the "wasted space" required for cryogenic storage. If you have a 100L petrol tank on your boat - you'll need to find about 400L of space to get the same range with your hypothetical hydrogen boat. Of course you can't just "pop in" any old place to refill it either so you'll need to carry extra...

willk · 05 April 2009, 22:02

Quote:

Originally Posted by Polwart

you'll need to find about 400L of space to get the same range with your hypothetical hydrogen boat.

hmmmm, high pressure tubes maybe?

.. just kiddin

codprawn · 06 April 2009, 14:39

Quote:

Originally Posted by Polwart

The energy density (i.e. number of Joules you can get from 1L of stored material) of liquid hydrogen is less than a third of petrol. And thats before you take into account the "wasted space" required for cryogenic storage. If you have a 100L petrol tank on your boat - you'll need to find about 400L of space to get the same range with your hypothetical hydrogen boat. Of course you can't just "pop in" any old place to refill it either so you'll need to carry extra...

I agree it does still have problems - a lot of them political. BP had some hydrogen filling stations back in the 90s but were forced to close them.

BMW still seem quite interested though.

http://www.hydrogencarsnow.com/bmw-hydrogen7.htm

The way forward could be higher pressure tanks - maybe spiral wound carbon fibre/kevlar.

I think it's main use though could be for power stations. Produce hydrogen from sea water - yes very wastefull but surely better than just switching on more and more lamp posts to try to deal with the night time surplus???

Poly · 06 April 2009, 15:03

So we are agreed that hydrogen isn't really a viable fuel for a rib at the current time!

chewy · 06 April 2009, 15:47

Or gas!

PeterM · 06 April 2009, 15:48

Quote:

Originally Posted by willk

hmmmm, high pressure tubes maybe?

.. just kiddin

As an aside - why couldn't normal fuel ( petrol etc ) be carried inside the tubes ? The flexible tanks AVON sell are hypalon I think ? Just stick one insude each side with its own connector ? Its protected from damage by the 'standard' part of the tube, deosnt affect bouyancy if its fitted right & uses all that 'free' space we drag around with us - oh its lighter than water to (just not as light as air !) so still helps us float - ( ok that bit is a bit open to question)

chewy · 06 April 2009, 15:51

Not sure how the small pressure inside the tubes would affect it.
The fuel bladders are good and usually laid between the deck and tube so you don't lose much space anyway.

PeterM · 06 April 2009, 15:59

Was thinking more to increase capacity . I guess the tube pressure would almost give you a self priming system - but you may need to deflate the tube to fill the flexi tank inside the tube otherwise you'd need a pressurised fueling system !

I'm sure someone has done it somewhere - realised its just not worth it moved on - or maybe they haven't & I am,despite apperance, a genius !

codprawn · 06 April 2009, 16:10

I think Bombard or someone did it before in a Zodiac non rigid across the Atlantic.

It would be a problem on a RIB because most of the tubes are out of the water - there would be a hell of a lot of unsuported weight. Probably get away with it in the aft chambers. A SIB wouldn't be a problem though.