Petrol V Deisel

ian38_39 said:
Volvo's figure's tie up fairly well with mine in that at 3500 rpm on my engines I am Burning about 8.5 Gallons an hour on each engine. 3500rpm gives me my normal cruising speed of 21-22 knots, can anyone fill in the figures for AD41's on a 310 statesman running at the same speed on diesels?

Ian
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That sounds about right, I have 32ft crusier similar hull to yours but no flybridge, 3500rpm gives 21-22 knots at 8.5 gallons per hour, but for both engines. Thats with AD31's, I suspect it would be the same or better with AD41's as the rpm would be much lower.
 
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ian38_39 said:
Which brings me back to my initial statement that petrol really does offer a viable option for those boating on a budget.

Ian

Ian
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Definately the answer is no, the catch 22 with a petrol boat is you can afford to buy it but can't afford to go anywhere. I boat on a budget and don't regret finding the extra for a diesel boat (previously owned a single petrol), i've used it much more and cruised further than I could ever have contemplated with a petrol boat. It is a harsh truth but twin petrols are ususaly only sold to newbies by desparate brokers who tell you about low hours and you'll never spend the difference etc... But even in the US where petrol prices made twin petrols viable, they are now taking them out and fitting diesels to save fuel and petrol is still only half the cost it is here.
 
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I think I read somewhere that less than 25% of boats moored in the Chichester Harbour area ever leave the harbour, so the price of a few gallons of fuel isn't going to make a huge difference to most boaters running costs.

Our boat is petrol, and on a nice smooth day it's great to open the throttle and wiz across the Solent - it's part of the fun of boating that we couldn't experience with a diesel.

I agree if you have a 30ft + boat and travel long distances, diesel makes sense, but how many people fall into this category?

MVP
 
ian38_39 said:
Mike thanks for that, if your figures are right that would mean that you were getting twice the range from your 305 than I am and also paying less than half for your Miles.

2.5 miles per gallon seems high to what I was expecting, how accurately did you check these? it is not that I am questioning your honesty it is just that it will form an important part of my calculations for a new boat.

From what I am told I can expect no better than 1 mpg for a 360 on kamd 42's. I assume due to extra weight and the inefficiency of shafts over stern drives. Even given that if you were achieving 2.5 mpg from your 305 it seems a big drop to 1 mpg on a 360.
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Sorry it was a long time ago (early '90's) but the figure is approximately right. Don't forget that the AD31's were 4 cyl lumps so relatively light and frugal although really vibey and noisy. I'm surprised you're being quoted 1mpg for the 360. Yes OK it's a heavier boat on shafts but I would expect 1.1-1.2mpg @ 20kts but maybe you'd reckon on 1.0mpg for planning purposes. I had a Sealine F43 with TAMD63P's too and that got close to 1 mpg
 
I think I read somewhere that less than 25% of boats moored in the Chichester Harbour area ever leave the harbour, so the price of a few gallons of fuel isn't going to make a huge difference to most boaters running costs.
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I'd imagine that figure is close to the number of boats not designed to be anywhere other than a harbour. Thousands of little saily thingys live in the harbour?
 
KevB said:
I'd imagine that figure is close to the number of boats not designed to be anywhere other than a harbour. Thousands of little saily thingys live in the harbour?
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And here is such a boat..really just a floating caravan..
Carversupersport.jpg


Paul
 
A major factor against petrol engines is the lack of proper fueling facilities in many area such as the west of Scotland
Having recentley had the fumes from a not that near boat being filled from cans blowing over I wonder what the acceptance of refueling in a marina would be ? Add that to the transportation of large numbers of jerry cans of petrol in a car.
How many laws and insurance term are being broken apart from the fact that it is dangerous
I suspect that most petrol engine fire are either during or just after refuelling.
 
I've owned a petrol boat and as a double whammy had 300ltrs of LPG on board as well. I always had a niggling feeling about the amount of high octane explosives on board. If there is a smell of petrol everything becomes very serious. The petrol isn't the problem it's the fumes.

With a diesel boat if you smell diesel the only worry is the hassle of finding the leak and clearing up the mess.

Don't mess with petrol fumes
 
When you buy you've got to think about selling, and petrol can be a turn off compared to diesel for prospective buyers. Also diesel is more economic even after the loss of red/green. Diesel is also safer and most importantly of all the most convienient to refuel (ie from fuel jetties and road tankers). There is a reason only small craft use petrol the world over.
 
Before thinking about KAMD 42's, have a look at the service records for these... they did have some issues around the cooling system, which is better on the 43's...

41's were good at 200 hp, 42's less so, but 43's were good again as cooling system and other issues were resolved at these high HP rating from such as small block diesel...
 
As I said in my first post 80% of my boating is on the Norfolk Broads where petrol saves me money, gives me a quiter smoother and less smokey ride and also gives me decent sized engine that are happy to travel at low speeds all day month or year.
Petrol for my current use saves me money. FACT.
The downside is trips to Asda with 100 litres of petrol in the boot.

Although my next boat will be diesel, this and my last have been petrol and Ihave to say I have enjoyed them both very much. whether I make the move will depend on whether I can convince myself that the financial risk is worth it.

To me the cost of a new engine, not to mention Turbo's or superchargers is a major fear factor.

how many diesel runners can say they have not had a bill over 5k for unscheduled repairs?
 
ian38_39 said:
.......how many diesel runners can say they have not had a bill over 5k for unscheduled repairs?
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Me... highest un-scheduled repair was for a new cooling water circulation pump for about £160.

But then again, I have engines older than 20 years, max out at 25 knots with 21 T displacement. Bought the boat in Salerno (South Italy) Sailed the boat home (NE Scotland) in autumn 2004 and have done most of the East & West Coast of Scotland since...

However, at 1.5 Ton each, my engines would not be suitable for a sportscruiser... nor would they fit into a modern flybridge's engine room.
 
Its not so much diesel engines that create large unscheduled bills - its lack of maintenance or outdrives that do it in my experience. If you keep a diesel engine well serviced and maintained it should go on for years - not always, granted, things do break - but they also break in Petrols too.
 
I had a £5k bill for unscheduled repairs on the first diesel boat I owned, but that was preventable. Change belts regularly = water pump keeps going = no overheat and the cylinder head gasket doesn't blow.

2nd and 3rd boats have run for hundreds of hours without going bang, apart from usual water pump, minor electrical bits, one heat exchanger end cap, but nothing too wallet-shrinking.

Biggest expense on the current boat was when the outdrive picked up some fishing line and ended up filled with oil and sea water milk shake.

dv.
 
maybe I am totaly up the wrong tree but I have looked at 3 boats with KADs in that have had rebuilds at less than 800 hrs, a friend bought a 2003 very well presented single engined 250 hp mercruiser engined boat the other week, fortunately through a very reputable dealer. I say fortunatley as it has now had a £8k rebuild, this was after he had last year got to survey stage on a very clean Draco flybridge before having the sale fall through due to engines about to go boom.

It may well be that he just finds boats that are kept nice but not mechanicaly maintained but he does find a lot of them.

I may be paranoid but what I am really hoping is that I can gain the confidence to move to something that burns diesel.
 
Ultimately you are going to find horror stories on both sides.

With petrols: cooling passages can clog up, risers and manifolds can fail causing catastrophic internal water leaks, plus ignition systems to get wet and die.

Diesels: tend to go wrong less often, but more spectacular and expensive when they do. E.g. cooling system problems which cook cylinder head gaskets or dropped valves, dodgy sensors or black boxes on the latest electronic diesels are not cheap.

For going longer distances in salt water, diesels still win. You might even find a pump at the other end to refuel and get back again :)

dv.
 
I agree you can buy a cheaper boat, save some interest and spend some of the saving on the fuel needed.

For me I am glad I went for diesel. I had my boat delivered, as I was not experienced enough at the time to colllect her myself. I think she took a bit of a pounding on the way and as we later found out the tanks were not in good condition.

When I went to the boat on probably the second occasion it was late and winter and dark. The first thing I did when I opened the cabin hatch was put my hand inside an switch on the light. Its then I noticed the smell. One tank and leaked about 25 galons of diesel and it had seaped into the bilges. I might have heard the BO but probably not the OM :D
 
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