Fuel consumption Sealine s34 /Cranchi Zaffiro

[DSWright1]

I am converting from a sailing boat to motor boat and I need some advice as regards fuel consumption.

Basically I am looking at a sealine s34 with Kad 41 200hp diesels. I wish to know approximately how many litres of diesel will be used in an hour at cruising speed. I understand that it is around 25 litres per hour (or is that a mistake and should be 25 gallons an hour?) I am just trying to guage exactly how much the fuel side of things will cost per hour on the water.

Another boat I am looking at is the Cranchi Zaffiro 34 fitted with 230hp diesels - I understand that this uses 50 litres an hour which seems like a significant difference for an extra 30hp.

Thanks, David

 

[gjgm]

I m sure someone will have the exacts.. but something else to consider.. when selling, the boat with the right engines will sell;the one with the wrong engines will be a nightmare to sell.
Also, we dont knw what fuel will cost from novemeber 08,, £1.20 -1.40 a litre are the guesses, up from about 50p at present.
Also, it may seem alot per hour, but it might make more sense to think of it as litres per mile. You go along way in an hour in a power boat ! The suggestion is 100 engine hours a year is normal, though that inludes tick-over, so maybe 75 cruising hours... I think many people are way below that figure too...

 

[MapisM]

You can find some Z34 figures on this recent thread.
Anyway, it's the 25 lph for twin AD41 that doesn't make sense.
Besides, the AD41 is a bit shabby for a 34' imho...

 

[Whitelighter]

The Sealine will use about 50 litres per hour at a steady cruise of 25 knts, assuming no adverse tide, clean bum etc etc.

That is effectively 2mpg, so pretty good. The 25lph figure you have been quoted sounds like a per engine figure to me.

 

[DSWright1]

Thanks. So basically my new hobby will cost around £60 an hour in a sealine 34. Whilst I am not totally averse to this, ideally I would be on use no more than 40 litres per hour at cruising speed - what sort of horse power should I be looking at? Perhaps I should start with a smaller boat to ease the transition from sailing - was also looking at a Bavaria 30 sport with 160hp diesels. Also will diesel be more expenseive than petrol once red diesel goes, and are petrol engines more efficient?

 

[Whitelighter]

It depends on what you want to do. You could look at a boat which has a single engine which will cut down on your consumption. Our W34 has the option of a single engine (D6 330 or 370) which uses about 35 lph at a gentle cruise 22/23knts. These are not so common because a lot of people like the security and peace of mind of a twin engine set up.

The other option is to go down to a smaller boat. Don;t make the mistake of thinking smaller engines in the same boat are worse - there is an amount of power needed to make the boat do that speed regardless - bigger engines just mean more top end and they are working less at cruise.

Another option is a newer, smaller boat with common rail engines. the newer ranges from VP and Mercruiser for example are more efficient that the older generation units like the AD41.

Sorry for mentioning our boats, but I thought it relevant.

 

[Whitelighter]

forgot to mention, I reckon diesel will be no more expensive than petrol at the pump next year, in factit will probably still be less (closer to the road rate). Diesel engines are inherently more efficiet than petrol lumps, you will go about 50% further for the same volume of fuel in a diesel boat.

 

[Deleted User YDKXO]

Er, how about going slower? Instead of wizzing about at 25-30knots, try 15-20knots and you should get significantly improved fuel consumption. As has been said already, do not buy a boat because it has small engines. You'll find it difficult to sell on and you won't get any better fuel consumption because those small engines will be thrashing their nuts off
Red diesel may be a little more expensive than petrol in the future because it's not low sulphur diesel like the road variety but it still makes sense for a number of reasons. Diesel engines are inherently about 25% more efficient than petrol engines, the fuel is much less flammable, it's much more widely available and, arguably, diesel engines are more reliable

 

[Whitelighter]

t 15knts an S34 will be sitting on the hump and being very inefficient. MPG wise, between 20knts and about 28knts on that boat will be about the same.

I don;t wnat to start this arguement again though /forums/images/graemlins/grin.gif

You could go for a semi-d boat like a single engined Nimbus 310 - nice and efficient and still capable of a good 14knts

 

[[2068]]

Consider an S34 with the smaller KAD32's.

You might not quite make 30kts, but it should burn something more like your desired 40 litres per hour at a (slower) cruise, which would be in the low 20's. I know there's a general rule that smaller engines in the same boat don't help economy, but for whatever reasons, KAD32's don't seem to burn as much juice as you might expect.

If you wanted more speed (34kts?), then you could go with KAD32's in a smaller boat, say a an S28, but then you lose the separate cabin up front.

Swings and Roundabouts...

dv.

 

[Deleted User YDKXO]

Blimey, still on the hump at 15kts? My fat lump of a boat is over the hump at 15kts so I would have thought a S34 is planing quite nicely especially with the tabs and drives down a bit? I bow to your greater knowledge /forums/images/graemlins/smile.gif

 

[[2068]]

An S28 will plane down to about 16kts with full tabs down, the drives trimmed in, and no under-thin people on the stern seat. It's happiest between 17 and 24kts, though.

I can't imagine the S34 is much different, maybe add a knot to the above figures?

dv.

 

[PowerYachtBlog]

Deleted User
while I know a Ferretti plains at 15 knots a Sealine with 2 x 200hp might just not do that
my Gobbi 27 Sport goes up at 2500 RPM and will be doing about 15/16 knots at that revs, drives down tabs up
the tabs cannot be used much, too much drag unless over 3000 RPM so better leaving them in all up
so I think a Sealine S34 would go up at about 17/18 knots
50 LPH for both engines would be a correct figure for the Sealine
I consune about 45 LPH at 3000 RPM which gives me 23/24 knots
similar conumsption between 2900 - 3100 over 3200 you go over the 50 LPH
230 KAD43 should consume a little more about 5/10% more but then it also depends the speed range of the boat in question
so if for e.g
1Sealine S34 2x200 HP for 25 knots needs 3400 RPM
2Sealine S34 2x230 HP for 25 knots needs 3100 RPM
boat 2 might in actual fact consue less altough equipped with bigger engines

the Ferretti plain fast for the reason that they have no tunnel props and is a pretty well balanced boat,
some of the models plain even at just 10/11 knots which is incredible and gives quite bad weather stability when you get stuck in heavy stuff....

 

[cloud7]

You are spot on , I have a S34 with kad 32, in the range 17 - 24knot, very economical 35 - 40 litres /hour which is excellent
for a 34ft boat . /forums/images/graemlins/smile.gif

 

[DavidJ]

KAD41's are getting a bit long in the tooth now so although I am a fan of Sealines (the old ones anyway) I would go for the 230hp's which I assume would be KAD43's and the Cranchi is a totally good boat with a good reputation and good second hand value especially in the Med.

 

[Sneds]

Our boat is 28ft with twin AD31P 150HP engines.
My rough estimation is at around 22 knots we are using 30LPH and flat out (32-34knots) around 50 or 60!
If you look at the MBM boat tests, in the mag, you will see that a slight reduction in speed will save a hell of a lot of fuel.
Allways, though, allways make sure you fill up when you can as adverse weather or going against the wind can dramatically increase your fuel consumption, as can having a dirty bum as the season progresses.

 

[Sneds]

Oh, BTW, at around 5 knots. 1500RPM, we use about 4-6 litres per hour!