On Wed, 23 Feb 2005 20:41:51 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

I run a 1985 Perkins 85 HP 4 cylinder pushing a 43'
boat. I consistantly burn 1 GPH.

==================================

If so, you are only using about 20 hp out of your 85 available. At
85% of full RPMs it should be burning about 3 gph unless you are way
under propped.

"Wayne.B" wrote in message
...
On Wed, 23 Feb 2005 20:41:51 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

I run a 1985 Perkins 85 HP 4 cylinder pushing a 43'
boat. I consistantly burn 1 GPH.

==================================

If so, you are only using about 20 hp out of your 85 available. At
85% of full RPMs it should be burning about 3 gph unless you are way
under propped.

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.

On Wed, 23 Feb 2005 23:51:31 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:
==================================

If so, you are only using about 20 hp out of your 85 available. At
85% of full RPMs it should be burning about 3 gph unless you are way
under propped.

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.

========================================

You obviously have plenty of reserve power which is nice for those
occasions where you are motoring into head winds and seas.

Actually, the original owner repowered the boat from a Perkins 4-108 to
a 4-236. The boat lived in Newfoundland. Fighting currents was
definitely his goal.

Doug
s/v Callista

"Wayne.B" wrote in message
...
On Wed, 23 Feb 2005 23:51:31 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:
==================================

If so, you are only using about 20 hp out of your 85 available. At
85% of full RPMs it should be burning about 3 gph unless you are way
under propped.

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.

========================================

You obviously have plenty of reserve power which is nice for those
occasions where you are motoring into head winds and seas.

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.



What RPM are you turning on that Perkins, Doug. Lionheart has a 4-108 I
got from a guy on this newsgroup in NC for $1200. In spite of the
boatyard's screwup flooding her exhaust and crankcase with seawater with a
dripless packing water injection line, she's a great engine. Our
econocruise is also very easy to get near hull speed on the Amel Sharki 41
ketch at around 2200 RPM, but she's nearly as fast at 1800. There's a 120A
house alternator mounted to port and the engine has a 90A alternator on its
bracket for the starting battery for some silly reason I have yet to figure
out. The new fridge is 12/120V so we took away all the car air conditioner
parts of the old French fridge/freezer combo.

The original Perkins that came with the boat ran just fine, even though the
hourmeter read over 7000 hours! Engine shop said it was still usable so
it's in the captain's garage in Atlanta, our spares repository of used
parts. Simply an amazing engine.....by anyone's standards.

"Larry W4CSC" wrote in message
...
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.



What RPM are you turning on that Perkins, Doug. Lionheart has a 4-108 I
got from a guy on this newsgroup in NC for $1200. In spite of the
boatyard's screwup flooding her exhaust and crankcase with seawater with a
dripless packing water injection line, she's a great engine. Our
econocruise is also very easy to get near hull speed on the Amel Sharki 41
ketch at around 2200 RPM, but she's nearly as fast at 1800. There's a
120A
house alternator mounted to port and the engine has a 90A alternator on
its
bracket for the starting battery for some silly reason I have yet to
figure
out. The new fridge is 12/120V so we took away all the car air
conditioner
parts of the old French fridge/freezer combo.

The original Perkins that came with the boat ran just fine, even though
the
hourmeter read over 7000 hours! Engine shop said it was still usable so
it's in the captain's garage in Atlanta, our spares repository of used
parts. Simply an amazing engine.....by anyone's standards.

I don;t actually know. The calibration of the tach is off because the
alternator is
not stock. When we first bought the boat I measured the actual RPM and made
a graph to convert from indicated to actual. Converting the proper cruising
RPM
to the indicated gives 2500 so that is where we run unless we need some
extra. I've forgotten what the actuals are. 1800 sems to stick in my mind
but
I'd have to go look it up.

Doug

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

I don;t actually know. The calibration of the tach is off because the
alternator is
not stock. When we first bought the boat I measured the actual RPM and
made a graph to convert from indicated to actual. Converting the
proper cruising RPM
to the indicated gives 2500 so that is where we run unless we need
some extra. I've forgotten what the actuals are. 1800 sems to stick in
my mind but
I'd have to go look it up.

Doug




Thanks. The 4-108 just seems to lazily cruise along in the 1800-2000 RPM
range. Lionheart has 90 gallons of diesel in the tank that's the starboard
seat in the center cockpit. It's amazing how long that lasts under power.

"Larry W4CSC" wrote in message
...
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

I don;t actually know. The calibration of the tach is off because the
alternator is
not stock. When we first bought the boat I measured the actual RPM and
made a graph to convert from indicated to actual. Converting the
proper cruising RPM
to the indicated gives 2500 so that is where we run unless we need
some extra. I've forgotten what the actuals are. 1800 sems to stick in
my mind but
I'd have to go look it up.

Doug




Thanks. The 4-108 just seems to lazily cruise along in the 1800-2000 RPM
range. Lionheart has 90 gallons of diesel in the tank that's the
starboard
seat in the center cockpit. It's amazing how long that lasts under power.

We have 2 95 gallon tanks. Great cruising range but having that much fuel
when
one only consumes 1 GPH has it drawbacks.

Doug

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

We have 2 95 gallon tanks. Great cruising range but having that much
fuel when
one only consumes 1 GPH has it drawbacks.

Doug



Fuel polishing is probably an issue, mostly ignored by sailors until it's
clogged the injectors or at least the filters. It always disturbs me how
so many sailors will just leave the tanks half empty all the time, instead
of topping them off before docking. Being down a gallon or two is probably
ok, but the condensation in a half-empty fuel tank of any size is just
awful here in Charleston.

It's just laziness. All those that have half empty fuel tanks all have
plenty of money to fill them.

http://www.gulfcoastfilters.com/fuel_polishing.htm

On Wed, 23 Feb 2005 23:51:31 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

"Wayne.B" wrote in message
.. .
On Wed, 23 Feb 2005 20:41:51 -0500, "Doug Dotson"
dougdotson@NOSPAMcablespeedNOSPAMcom wrote:

I run a 1985 Perkins 85 HP 4 cylinder pushing a 43'
boat. I consistantly burn 1 GPH.

==================================

If so, you are only using about 20 hp out of your 85 available. At
85% of full RPMs it should be burning about 3 gph unless you are way
under propped.

Scoots me along at just under hullspeed. Last surveyor said it was
propped just fine.

I do 5.8 knots at 1/2 throttle on a direct drive Atomic 4 with a 12" x
6" "standard" two-blade prop pushing a 10,000 lb boat with a 27' LWL.
Hull speed is just under seven knots. RPM is around 1,500-1,600.

I can get to 6.6 knots SOG at 3/4 throttle, but the noise is
unpleasant and I start burning a lot more gas...it's not worth it.

I can sail in heavy air favourably angled slightly above hull speed
(7.3 knots SOG) for sustained periods, or about 1.5 knots

I have logged a pretty consistent gas usage of 0.73 Imp. gal/hr. which
is about .825 U.S. gal, I think. That's at a typical cruise speed of
1/3 throttle or 5 to 5.2 knots. A 12 gallon tank gives me a range of
about 84-90 NM or just under two round trip Toronto-Niagara River
crossings. Motorsailing increases this significantly, of course.

If I drop it to 4 knots, I burn one half gallon an hour. This means 24
hours of constant use and nearly 100 NM of range. (It's a
racer-cruiser, not a passagemaker).

I only use full throttle in reverse, actually...if ever.

The point? You pay hugely in fuel consumption and engine wear getting
that last knot.

R.