wrote:

The boat I planning on having has
a three cylinders engine and only a 20 gals tank. At time, when a
storm or
hurricane is behind you may have to make a mad dash in light wind
condition
to reach a safe heaven. Then 20 gals of fuel may not be enough to
reach the
safe heaven. What would be the best way to carry extra fuel?

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+).

If hull speed is 6 MPH, that is 300 statute miles which probably
allows you to get to a lot of safe havens.

OTOH, if you are in the open ocean, no amount of fuel is going to save
your hide.

Lew

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.

You can figure .054 to .06 gallons per horsepower hour depending on things
like how much electric power is being drawn and the effeciency of the
specific engine. Those of us living the simple life seldom run our engines
except to move the boat.

--
Roger Long

* Roger Long wrote, On 6/6/2007 5:16 PM:
....
Those of us living the simple life seldom run our
engines except to move the boat.


IIRC, your cruise last year was only a week ... hardly enough time for
a block of ice to melt in Maine. ;-}

And I'm guessing you didn't exactly live the "simple life" on the
Titanic venture, even if trip to the bottom was a bit spartan.

On Wed, 6 Jun 2007 17:16:39 -0400, "Roger Long"
wrote:

You can figure .054 to .06 gallons per horsepower hour depending on things
like how much electric power is being drawn and the effeciency of the
specific engine. Those of us living the simple life seldom run our engines
except to move the boat.

My definition of serious cruising is 3 to 6 weeks in the boondocks
where fuel is either totally unavailavle, of dubious quality, and/or
prohibitively expensive.

Most of the coastal north east has a fuel dock every 20 miles or so
and 20 gallons would be plenty as long as you go into town once a
week.

Wayne.B wrote:


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.


OK, use your numbers.

Assume only 10 gal in the tank and 3 qts/hr consumption.

(10*4)/3 = 13+ hours.

If you haven't found safe haven in 13 hours, you are probably in deep
doodoo.

Ran a 30ft sloop with a one lunger and a 10 gal tank for years.

Out on a 2,500 mile cruise, it was a big deal if I bought 6-7 gallons
at once.

That's why those boats have rags, so you DON'T have to listen or smell
the damned engine when you want to go someplace.

Lew

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
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

On Thu, 07 Jun 2007 01:05:04 +0100, Ian Malcolm
wrote:

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)

My engine is actually a 27 hp 4 cyl and drives my primary generator.
At half load it burns about 1 gal/hr. Extrapolating downward 25% or
so is where my guesstimate came from. The traditional rule of thumb
for diesels is 1 gph for every 17 hp actually developed.