Wayne.B wrote:
On Wed, 06 Jun 2007 16:24:31 GMT, Lew Hodgett
wrote:


What is the max fuel consumption rate of that 3 cyl engine, about 1.5
quarts/hour maybe?

A 20 gal tank would provide over 50 hours of operation ((20*4)/1.5 = 53+).


A small 3 cyl diesel will typically burn around 3 qts/hr (.75 gal).
Range is only part of the issue. Most cruisers run the engine 2 or 3
hours per day for battery charging, hot water, etc.

A typical small normally aspirated marine diesel will burn about 1/3 of
a litre per kilowatt hour (1/4 litre per HP hour if you prefer mixed
units). Thats near enough 1/2 a pint per HP hour. Just multiply by
your engine's max continuous output rating to get an idea of the max
fuel consumption. Better still, get the maufacturer's spec sheet and
look up the consumption for your cruising RPM.

The numbers I give above tie in pretty closely with observed results for
our 26 footer with a Yanmar 1GM10, where we normally motor at around 3/4
throttle and the rated continuous output power is 8 HP. The tank is 18
Litres when filled to the brim and we used about 20 litres (topping it
off from cans part way) on a 100 M, 15 hour passage from the Thames to
Calais a fortnight ago. Any discrepancy can easily be accounted for by
time spent dodging round a large fishing net (thankfully lit) at
reduced speed in the middle of the TSS and what assistance I was able to
get out of the sails in the light airs we had.

Incidentally, for the OP, we usually carry enough gallon cans in the
stern locker to refill the tank twice. So thats just over 4 1/2 US
gallons in the tank and 9 gallons reserve.

That tank will do OK for a day tank if we go off blue water but as the
filler is on the side deck and we have a low freeboard, I'll need to
fit a larger main tank with a transfer pump or at least some way of
refuelling at sea *without* taking the cap off the filler. I also need
to look at fuel polishing (help keep the tank clean over the winter +
its better to find you have been sold contaminated fuel *before* you
leave port).

Wayne, your 3 quarts per hour figure seems a little low or do you
usually cruise at half throttle? (I'm guessing your engine is around 25
HP as there is little point in haveing a 3 cylender diesel rated at
under 20 HP)

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
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