What range do you have?

MapisM said:
I was going to make the same question.
As I recall from a previous thread, PF mentioned that his typical fuel burn is 180 l/h at a cruise speed of 27/28 kts.
So, he should burn around 2500 litres to make 377Nm, and that's without considering any reserve.
Sounds like a helluva tankage, for a boat like his... :confused:
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Each boat approx 21 was built to order .Mines hull no 12 .
STD 800 x 2 tanks straddling the centre geny behind the central ( relative to the boat vol ) engines .Tanks are behind the gearboxes trapezoid shaped into the V .Behind those is a bulk head of the twin + en-suite stern cabin - where most boats have an ER .
No owners fwd shower room , dinette enlarged , bigger day heads in lieu of seperate shower with a connecting door to the fwd owners cabin .AND and extra long range tank on the stb side of another 800 , so 3x800 ,
There are two fuel fillers on the stb side deck and one on the port deck .

All three tanks are interchangeable by various cocks / valve s in a suede rubricks cube esk way :)

When the LR tank is full , despite the slight internal rearranging less kg on the stb side due to loss of shower room ,the boat lists to stb it’s quite visible and the slime tide mark @ haul out looks odd to say the least .
This summer after checking it for the dreaded bug I opened up the various cocks connecting the three tanks up and emptied the reserve .
I think I’ve been running round with a spare 800 L for the past 3 years totally oblivious.
There’s no guage or sight glass so you can’t tell what’s in it .
I did it by tapping all three tanks the main two are guaged and sight glassed so I worked out by the tap sound the reserve must have been full . It was ,
Funnily enough I was on the boat last WE with about a 1/4 or less in the two main tanks and it felt it now lists ever so slightly to the port side ,but only a v tiny list ,
I always dose with diesel anti bug even in the summer and a big dose at the last fill up before the winter .
Well the 3 + year old 7/800 L reserve, like a fine wine seemed ok when the engines drank it .Its empty now as it’s mounted ( straight rectangular shape ) higher then the inlet on the main on the stb side .So with the relivant cocks open you can empty it .

Not sure why the original owner specced the LR tank ,but he’s a serial Itama owner with a hotel on Capri and uses the boat for Naples taxi and day trips .Fiammetta 3 is a XL 51 made in the same yard by the same guys with the old moulds in Roma .
 
View attachment 74576
Stb see the two white lines the lower is about submerged midships were the extra 800 L has been sitting

View attachment 74577

Port side the lower of the twin stripes is 4/6 cm above the water .

It sits more or less level now despite the new heavier tender offset to stb on the bathing platform .

Water tanks a whopping 500 L for the boat size that’s under the saloon cabinsole - v shaped to the keel glassed in .
So fully loaded it’s down to lower white stripe , and loosers a knot or two initially carry all that weight .
 
On the subject of fuel burn, could someone explain the difference between "Full load" and "Calculated Propeller Load" and tell me which I should use?

IMG_20181014_165127.jpg
 
VERY intriguing explanation PF, thanks for it.
Though I would guess that the train of thought behind that choice is that the boat is supposed to be normally used with the LR tank empty, except when really necessary, for obvious performance/balance reasons.
In other words, exactly the opposite of what you did in the last 3 years... :)

What are the fuel tanks made of, s/steel? Aluminum? Or are they structural, i.e. built in solid grp and glassed to the hull - as mine and some Ferrettis are, for instance?
As I understand, the latter is how your water tank is made, so I guess that they might have taken the same (not very usual, actually) route also for fuel.
Besides, do you possibly have a layout drawing which you can post?
Btw, this could well be worth a new specific thread on builders' choices (both layout and material) on onboard tanks.
 
petem said:
On the subject of fuel burn, could someone explain the difference between "Full load" and "Calculated Propeller Load" and tell me which I should use?
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Neither P, I'm afraid. :D
The full load curve shows the max power that the engine is capable to deliver, while the prop load curve is the actual power required by the prop.
Which might lead you to think that the latter is the only meaningful curve, which is kind of true, if it weren't that it is theoretical, and normally calculated with a correction coefficient which follows the linear behaviour of a displacement boat.
The "real" prop load curve should empirically be calculated on each boat, and btw it is affected also by load, hull cleanliness, etc.
Easy peasy if you've got electronic engines showing the load in real time, but if you don't, the manufacturer theoretical prop load curve is the best approximation you can get.
 
MapisM said:
Neither P, I'm afraid. :D
The full load curve shows the max power that the engine is capable to deliver, while the prop load curve is the actual power required by the prop.
Which might lead you to think that the latter is the only meaningful curve, which is kind of true, if it weren't that it is theoretical, and normally calculated with a correction coefficient which follows the linear behaviour of a displacement boat.
The "real" prop load curve should empirically be calculated on each boat, and btw it is affected also by load, hull cleanliness, etc.
Easy peasy if you've got electronic engines showing the load in real time, but if you don't, the manufacturer theoretical prop load curve is the best approximation you can get.
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Thanks. Would a figure of c. 40lph per side @ 3000rpm (slight chop, clean hull and 100% loaded with fuel and cruising gear) therefore be within expected parameters? That's what I seem to be getting.
 
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petem said:
Thanks. Would a figure of c. 40lph per side @ 3000rpm (slight chop, clean hull and 100% loaded with fuel and cruising gear) therefore be within expected parameters?
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Yup, I would say so. According to the charts you posted, 40lph is just about half way between the prop load curve, which as I said is only theoretical, and the full load curve, which is the limit (both in terms of output and fuel consumption) above which the engine should never go, unless defective.
I mean, the engine will NEVER go above that curve in terms of output of course - that would rather be a miracle than a defect :D.
But it could burn more fuel, due to some leaking injectors, defective pump, or whatever - which in turn should make the engine unusually smokey, btw.
My understanding is that this can indeed happen in MAN engines for instance, whenever one or more nozzles are worn out.
I see no reason why the same couldn't happen in other engines, though I'm happy to be corrected by volvopaul or any other folks who know VP engines much better than myself.

Btw, am I wrong in remembering that the 44 series is the latest of KAD engines, and that it is electronically controlled?
If so, you should be able to check the real time load on some instrument, or maybe you could add one, if not originally fitted.
That's a very useful number to have (together with EGT), if possible.
Even more than fuel burn, imho.
 
MapisM said:
Yup, I would say so. According to the charts you posted, 40lph is just about half way between the prop load curve, which as I said is only theoretical, and the full load curve, which is the limit (both in terms of output and fuel consumption) above which the engine should never go, unless defective.
I mean, the engine will NEVER go above that curve in terms of output of course - that would rather be a miracle than a defect :D.
But it could burn more fuel, due to some leaking injectors, defective pump, or whatever - which in turn should make the engine unusually smokey, btw.
My understanding is that this can indeed happen in MAN engines for instance, whenever one or more nozzles are worn out.
I see no reason why the same couldn't happen in other engines, though I'm happy to be corrected by volvopaul or any other folks who know VP engines much better than myself.
Click to expand...

Thanks. No smoke from my engines at all which is a relief.

MapisM said:
Btw, am I wrong in remembering that the 44 series is the latest of KAD engines, and that it is electronically controlled?
If so, you should be able to check the real time load on some instrument, or maybe you could add one, if not originally fitted.
That's a very useful number to have (together with EGT), if possible.
Even more than fuel burn, imho.
Click to expand...

Yes, it's electronically controlled. You can buy a gateway adapter to Seatalk NG but it doesn't display load or EGT. The measurements that it does display include rpm, lph, turbo boost, water temp and engine hours. I'd be very interested to see boost and fuel consumption, particularly the latter if it could show how much fuel has been burnt since the last fill up. Problem is that it would be a bit of a pig running a cable from the ECU to the dash.
 
petem said:
You can buy a gateway adapter to Seatalk NG but it doesn't display load or EGT.
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Aha, I see. In this case, I'm not sure I'd bother fitting the adapter and snaking the cable to the helm, in your boots.
I'm not saying that fuel burn and all other numbers are useless of course, but load and EGT, more than anything else, are what really tell you how the engines are working.
Besides, for checking how much fuel is left, I would never rely on anything else but sight gauges, regardless of any other instruments - in fact, the DP didn't have them as original installation, but I had them fitted.
And once you get the hang of checking fuel level on sight gauges, you can work out also a pretty accurate fuel burn measurement.
Not in real time of course, and it takes a bit of math to get the L/H or the L/Nm, but at the end of the day who wants to keep an eye constantly on a real time fuel burn number?
That's already mad enough on P boats, without being stressed by a constant reminder on the dashboard! :D
 
Aha, I see. In this case, I'm not sure I'd bother fitting the adapter and snaking the cable to the helm, in your boots.
I'm not saying that fuel burn and all other numbers are useless of course, but load and EGT, more than anything else, are what really tell you how the engines are working.
In fact as I’ve said on other threads it’s what I set my cruise at the load ,
I just adjust the rpm to 80 % load and leave it there with a glance at the EGT,s to check they are within the correct range namely 550 -600 .
I don’t like going N of 600 in fact back off if I see that ,
It’s amazing what the prop / sterngear hygiene has on its effect on EGT and load .
I,am wearing an engine longevity hat picking out those two ( on the same page ) of the 16 other parameters spread out on 4 pages on the screens .
Besides, for checking how much fuel is left, I would never rely on anything else but sight gauges, regardless of any other instruments - in fact, on the Itama they are original installation, and like MapisM I look at them every day .
And once you get the hang of checking fuel level on sight gauges, you can work out also a pretty accurate fuel burn measurement in cm used .
Tend to work on which day I,am gonna fill up because I can see the increments used on the sight glasses.

If you are gonna fit sight glasse(s) they are actually plastic pipes transparent in U shaped protective shield with a seperate cock to make them live or dead and a push primer button to momentarily get a reading .
Obviously when runing I turn the cock off ( sos if they leak for any reason ) I just loose what’s in the pipe .
While you are making holes ask the fitter to fit a drain cock at the lowest point - handy to see fresh fuel drain out as opposed to black stuff if the boat been stud idle .
I fact the fitter may be able to adapt in your case the cock for the sight glass into a drain dock as well = one hole .
 
In a flybridge you have the engine room boxes and then boxes at the upper and lower helm.

I assume in a sports boat you will still have one at the lower helm which connects instruments and throttles. Hence no running of wires
 
Portofino said:
in fact, on the Itama they are original installation
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R U sure? As I was told, the only reason why sight gauges were not OEM fitted in DPs is that RINA used to turn their nose up to them.
I would guess that this background should apply also to Itamas, as well as any other IT builders.
Alternatively, RINA engineers were maybe less strict with southern builders, which is a distinct possibility! :rolleyes: :D
 
jrudge said:
Hence no running of wires
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Why not, J? I understand that if you have all the existing cables routed through a single box, both inside the e/r and at the helm(s), it might be a bit easier to route another wire through the same pipe.
But you surely can't use one of the existing cables for a completely new purpose, I reckon?
 
My (600l) fuel tank is in front of the engine room bulkhead in a dedicated space so there is very little room at the sides or above it for sight gauges. Besides that, the hatch is heavy and doesn't have any struts so is hard to lift. Removal of the tank would be a doddle but checking sight gauges (if you could even fit them) would be a pain.

This post has got me thinking though, I'm not sure how tall the tank is and what's below it. I guess it's just a void. Interestingly (for me), I believe that where a Genset was spec'd the fuel tank was split to make space for it. I'd be interested to know exactly how this was done (Stelican?).
 
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