Fuel Consumption for twin V8

[oldgit]

I disagree totally (with the exception that fuel will rise, and not just petrol) - I have never been stopped from filling up 4 cans, and also have never had to fill more than four in one go - and I am talking from experience!

Forecourt notices prohibit you from filling up anything other than those small containers .You are simply not supposed to do it and if the cashier spots you he will stop you,its his/her job.
You are not allowed to store more than a very small quantity of fuel anywhere either .
Marinas normally forbid filling boats from cans ,apart from titchy outboards etc.
And as for driving around with 3 or 4 25L plastic petrol cans in your car ?
Been there done it.
No getting away from the fact if you to fart around locally than petrol is OK,if you are prepared to lug supermarket petrol around or cough up marina prices,from the few that bother to stock it.
But if you actually intend going anywhere...forget it.

 

[Barleycorn]

When I have to fill up jerry cans I put them on the back seat, and fill them through the back door making sure I am facing away from the Kiosk. Never had a problem. Like most other things you get away with it if you're sensible.

Also a decent fitting pouring spout for the jerrycan makes filling a lot easier than using a funnel.

 

[julians]

Surprising that petrol is hard to come by in UK marinas. IN mallorca all the marinas I know of sell petrol and diesel. Aside from the increased fuel consumption compared to diesel, its not a problem having a petrol powered boat in mallorca.

 

[Greenheart]

Maybe worth having your own pipe & 12v pump for emptying the vehicle's fuel tank, so you can perfectly legally (and safely, and much more easily) put 90 litres in there, then pump it into the boat's fuel tank later?

 

[[2068]]

Maybe worth having your own pipe & 12v pump for emptying the vehicle's fuel tank, so you can perfectly legally (and safely, and much more easily) put 90 litres in there, then pump it into the boat's fuel tank later?

Quite a few newer cars have anti-syphon devices that would stop that.
But it would work with an old Jag or Rangie

 

[aquapower]

Maybe worth having your own pipe & 12v pump for emptying the vehicle's fuel tank, so you can perfectly legally (and safely, and much more easily) put 90 litres in there, then pump it into the boat's fuel tank later?

Don't think I would like to use 12v pump, if you going to do it then syphon will be safer.
I use to leave cans in back of car as said above, only got noticed a couple of times but on a busy forecourt it doesn't usually get noticed. Tesco was the one that would usually say something.

 

[BruceK]

The fact that you get away with it does not make it clever. Loose jerry cans in the back seat, the day you have an accident you may not regret that action for long. Explosive airbags and petrol, talk about going out with a bang.

 

[Greenheart]

I was under the impression there are 12v pumps which are specifically insulated in order not to produce sparks.

Perhaps Vetus or Plastimo make a shape and size of tank which could sit squarely in the boot (trunk) and swallow 100 litres without requiring individual lifting/tipping/concealment at the fuel station. In combination with a spark-free pump and a decent length of hose, it sounds less hassle than an assortment of jerrycans, which only contain enough to let the boat limp home.

 

[BruceK]

Just buy a bowser. You can get one for under a grand on fleabay

 

[Barleycorn]

The fact that you get away with it does not make it clever. Loose jerry cans in the back seat, the day you have an accident you may not regret that action for long. Explosive airbags and petrol, talk about going out with a bang.

Have a look at this, how they test Jerrycans

www.youtube.com/watch?v=25PDRWXnGKg

I suppose the worst is they could hit you on the head in a collision, but I was brought up in the sixties when us five kids sat across the back seat of the Vauxhall Wyvern, not a seat belt in sight, and survived many trips throughout England and Scotland. That must have made me the Cavalier that I am!

 

[ian38_39]

Sorry but I have just sold a petrol boat with twin 4.3 volvo V6's and the only thing that would stop one selling is people saying that you shouldn't buy one. the boat was a Sealine 310 statesman so 34' with a flybridge. By The Way it sold in 4 Days, I'm sure all the oil burners will struggle to beat that

Our use 70% river Norfolk Broads 3 trips out to sea a year two of 1 week and one of 2 weeks, maybe a couple of short trips on a weekend apart from that.

At sea she cruised at 3400 rpm giving 20 knots and averaging 1.5 miles per gallon, yes the equivalent diesel may do 2 mpg but on the river they were neck and neck, at around 1 gallon per hour.

In our use the difference was somewhere around £400 a year, hardly significant in a years boating costs. Maintenance was cheaper and easier, reliability was 100% through 7 years and bearing in mind that the boat was 22 years old, diesel or petrol at some point soon the engine is going to suffer a major issue, if it does then £2500 will put you a brand new lump in my old boat, how much is a new 200hp diesel going to cost you and how many years at £400 a year is it going to take to make it up?

Getting petrol can be a pain, yes we had to fill 5 jerry cans at a time from the petrol station but in 7 years only once had someone tell us we couldn't. the cans were tight in the boot and couldn't move so I just filled them there.

in a car you can put legally 2 x 10 litre jerry cans, individual licensing at fuel stations may limit what they can dispense into cans but that is the fuel station license not the law. if you use a van it goes to 300 litres or if you take a fire course and carry the right extinguishers it is a lot more. not sure I would be using the extinguisher but there you go.

We slept soundly at night with the comfort factor of no matter what happened to our old boat we could afford to repair it. Not so sure that is the case now we have a couple of Tamd 63p's.

Petrols, dependent on use have a great deal to offer but you can not deny if you are going to do serious passage making at sea. something that probably less than 5% of boat owners do. you would be better off with a diesel.

 

[oldgit]

Well done for selling your old boat so quickly. I will give it 6 months at most before your first post appears slagging off petrols and outdrives.
A nice pair of proper engines presumably with reliable drive system in a boat actually capable of going in a straight line
So what did you buy then ?

 

[ian38_39]

A Sealine F43, Trust me I am already having nightmares priced up an intercooler for it the other day out of interest, it is more to buy than it would have cost me to have a new engine fitted in the old boat, and that is not an exaggeration.

Have not had the point where things get cheaper because of moving to diesel and getting less fuel cost. Yes the boat has got a lot bigger but it will still cost more in fuel per mile to run than my petrol boat did.

I really do after 7 years ownership believe petrol's have a place. don't run them flat out unless you do want to empty your wallet but treat them kindly and they will serve you well for not much more money than a diesel. they will also cost you a lot less when things go wrong.

 

[BruceK]

If you are boating on the Broads or similar petrol could make perfect sense. I remain to be convinced that if you were sea based you'd be singing the same tune of £400 p.a. While I was looking for boats I spent a bit of time at NYA at the broads and there were a good number of excellent condition petrol engined boats. But as the speed restrictions there negated the cost differential between the two fuel types and consumption your argument w.r.t. maintenance is very valid, I just don't think it's transferrable to saltwater boating where you will spend most of your time on the plane rather than hull speeds or slower.

 

[ian38_39]

Would absolutely agree that if you are going to spend all your time at 20 knots plus Diesel is the only sensible choice, but if most were to be honest about the amount of hours they spent at that speed per year, and even if they were to double the amount that they spent on fuel for that time, it would still not be that much in a years costs.
We used to cover between 400 and 500 miles over our 4 sea weeks, this is probably more than the majority of sea boats do in a year any way.

Most of the problem with petrol is getting it, if it is not available where you boat it is a pain, then there is the fact you only see your annual costs once a year and they are so big a few hundred makes no difference. When you fill with petrol you see it each time you pull up to the pumps and as a percentage £50 or £60 becomes a lot, especially when you are cruising with the same boat with a diesel engine.

 

[BruceK]

A simple calculation of what it would coast me per month budget in fuel for my boat if I just averaged 3 hours cruising every weekend in the season or ~ 75 hrs p.a. (3 hrs x 25 weeks). I have KAD42's their petrol equivalent would be the Penta 4.3 V6 or smallest V8. As the V6 is marginally more fuel efficient at cruising speed we will stick with that.

Diesel
2 x KAD42 diesel ~230HP @ 20 liter x2 per hour at cruising revs 3200 rpm (personal consumption observation)

diesel at my marina 89pence liter

(40 litre per hour x 75 x 0.89) / 6 (months) = £445 per month in the season

Petrol
at forecourt (marina more expensive) 1.15

2 x Volvo Penta 4.3 V6 ~225HP @ 38 liter x2 per hour at cruising revs 4200 rpm (reported consumption observation)
(76 liter per hour x 75 x 1.15) / 6 (months) = £1092 per month in the season

I boat on a budget, petrol would limit my hours useage, in fact make it miserable as I have given myself a budget of £12k p.a. to play with at this hobby.

 

[ian38_39]

Can only add to that that we cruised at 20 knots at 3400rpm with V6's which gave us a usage of roughly 60 litres an hour.

Even using the personal consumption over the reported it would still make diesel the heavy favourite, especially if you get your diesel as cheaply as you do. On the Broads it is around £1.10 litre

Using Broads fuel prices for diesel and actual consumption for petrol and running for 50 hrs a year, (which is average use) and doing all of this at 20 knots, (average is 10 knots) the annual difference would be £1250 but this is based on all sea use where you would expect diesel to be cheaper. Even then if you bring down the speed to an average 10 knots taking in marina time, approaches etc the difference would be down a lot more.

Obviously these are all rough figures as I don't know what boat you are using as a basis for your calculations and with Kad 42's it is probably bigger than the 310 statesman I am basing mine on but it does stand to reason that the bigger the boat the more likely it is that diesels will be the engine of choice, not just for fuel use but also torque.

Would still maintain that if there is a mix of boating across river and sea the figure will be so close as to make no difference.

 

[subra]

Thanks for all the replies, some excellent advice and i appreciate it. Really for someone like me with little to no boat knowledge its invaulable to have a pool of infomartion like this.

I plan to use a mariner which is around 8 nautical miles from the sea with a 6 knot limit until then. Im assuming this will give me more than 1 mile per gallon?

When out to sea it will be opened up which is where im going to be using a lot of fuel i presume, running around 30 knots for an hour for instance which i assume will use 1 mile per gallon?

Just got my RYA powerboat level 2 today so will hopefully be getting either this boat or, should it be deemd to expensive to fuel, a different one within the next week or so.

Thanks

Thanks