Howdy group,
All the yachtsmen I know who run a diesel use only 'diesel fuel', which
is light and expensive. However, in the merchant navy we use bunker
fuel whenever we're going to be running the engine for a long time,
without varying RPM.

It's thicker than molasses at room temperature, but when suitably
heated, it runs enough to be used in a diesel engine. It also costs a
fraction of regular 'diesel fuel' (aka "Champagne"). The engine is
started with light diesel fuel until it's running hot enough, then the
fuel mixture is gradually changed over to bunker. If the ship comes to
manoeuvering conditions, then the mixture is switched back to light
fuel. They always go back to light fuel before shutting off the engine,
too, to 'clean' the insides for the next start-up.

Now I'm wondering why we don't do this in cruising yachts, where the
engine is running constantly for days, especially considering the fuel
prices of late. All one would need is a heated holding tank and a way
of adjusting the fuel mixture. Then again, I'm not a marine engineer.
Am I missing something?

Regards,
-Max

Hi

In the old day's there was plenty petrol engines that had a double
caburator , to switch between petrol and the heavier petrolium ( a
ligther sort of Diesel fuel ) .
For an old fasion 4 stroke slow running marine petrol engine, this also
work best, if the fuel are pre-heated, usealy by the petrolium tube
turned around the exhoust pipe , but also the air intake running thru
the exchoust pipe, help a lot pre-heating the more heavy fuel, when a
switch turn the gasolin chamber of the caburator to standby, and the
fuel was taken from the opposite chamber with petrolium.
------- the problems was the same ; the engine had to be started with
petrol on, but warm it ran well enough on the cheaper petrolium, and
the double caburator, made it so that only a switch needed to instantly
turn off the petrolium side so the engine would run more safe , say
when entering a harbour.

wrote:
Howdy group,
All the yachtsmen I know who run a diesel use only 'diesel fuel', which
is light and expensive. However, in the merchant navy we use bunker
fuel whenever we're going to be running the engine for a long time,
without varying RPM.

It's thicker than molasses at room temperature, but when suitably
heated, it runs enough to be used in a diesel engine. It also costs a
fraction of regular 'diesel fuel' (aka "Champagne"). The engine is
started with light diesel fuel until it's running hot enough, then the
fuel mixture is gradually changed over to bunker. If the ship comes to
manoeuvering conditions, then the mixture is switched back to light
fuel. They always go back to light fuel before shutting off the engine,
too, to 'clean' the insides for the next start-up.

Now I'm wondering why we don't do this in cruising yachts, where the
engine is running constantly for days, especially considering the fuel
prices of late. All one would need is a heated holding tank and a way
of adjusting the fuel mixture. Then again, I'm not a marine engineer.
Am I missing something?

Regards,
-Max

THere's more than the heated day tank, you need separators
to deal with the sludge, a place for the sludge (sludge
tank), etc. etc. Most pleasure sailboats turn off the
engine and sail so you don't have a ready source of heat to
keep the fuel tank warm....

Oh, small engines just won't run on heavy fuel either. The
fuel pump on a small (say 50 HP) engine pumps out such tiny
amounts of fuel with each stroke that it probably couldn't
meter it if it were heavy fuel.

Evan Gatehouse

OK I'll let all my chemistry ignorance hang out and ask. Would it be
practical to brew your own deisel by mixing bunker with regular
gasoline? Would the savings be worth it?

wrote:
Howdy group,
All the yachtsmen I know who run a diesel use only 'diesel fuel', which
is light and expensive. However, in the merchant navy we use bunker
fuel whenever we're going to be running the engine for a long time,
without varying RPM.

It's thicker than molasses at room temperature, but when suitably
heated, it runs enough to be used in a diesel engine. It also costs a
fraction of regular 'diesel fuel' (aka "Champagne"). The engine is
started with light diesel fuel until it's running hot enough, then the
fuel mixture is gradually changed over to bunker. If the ship comes to
manoeuvering conditions, then the mixture is switched back to light
fuel. They always go back to light fuel before shutting off the engine,
too, to 'clean' the insides for the next start-up.

Now I'm wondering why we don't do this in cruising yachts, where the
engine is running constantly for days, especially considering the fuel
prices of late. All one would need is a heated holding tank and a way
of adjusting the fuel mixture. Then again, I'm not a marine engineer.
Am I missing something?

Regards,
-Max

THere's more than the heated day tank, you need separators
to deal with the sludge, a place for the sludge (sludge
tank), etc. etc. Most pleasure sailboats turn off the
engine and sail so you don't have a ready source of heat to
keep the fuel tank warm....

Oh, small engines just won't run on heavy fuel either. The
fuel pump on a small (say 50 HP) engine pumps out such tiny
amounts of fuel with each stroke that it probably couldn't
meter it if it were heavy fuel.

Evan Gatehouse

Proberly not, as the more heavy fuel also carry acids and sulfur there
simply are more dirt in the heavy fuels, something that is no problem
in a huge ships engine undertaking maintaince on regular times ,where
the pistons are houled and the rings cleaned every 2 month and, you
easily end up with an engine blocked by unburned remains, valves that
will not close well, all in all , what you think you save can add extra
costs while the engine suffer. ---- beside when the engine are not made
for the fuel the smoke can turn out to be a major problem.
Also even the old slow running engines are made for a particular fuel,
the jets in the carburator aswell as the spray holes in the diesel
engine, are made so that a wrong fuel will only caurse trouble , the
engine will turn out being very "dirty" and esp. more modern engines
will soon fail or the engine will soon be vorn out.

that makes sense thanks

Proberly not, as the more heavy fuel also carry acids and sulfur there
simply are more dirt in the heavy fuels, something that is no problem
in a huge ships engine undertaking maintaince on regular times ,where
the pistons are houled and the rings cleaned every 2 month and, you
easily end up with an engine blocked by unburned remains, valves that
will not close well, all in all , what you think you save can add extra
costs while the engine suffer. ---- beside when the engine are not made
for the fuel the smoke can turn out to be a major problem.
Also even the old slow running engines are made for a particular fuel,
the jets in the carburator aswell as the spray holes in the diesel
engine, are made so that a wrong fuel will only caurse trouble , the
engine will turn out being very "dirty" and esp. more modern engines
will soon fail or the engine will soon be vorn out.

In article .com,
wrote:

Howdy group,
All the yachtsmen I know who run a diesel use only 'diesel fuel', which
is light and expensive. However, in the merchant navy we use bunker
fuel whenever we're going to be running the engine for a long time,
without varying RPM.

It's thicker than molasses at room temperature, but when suitably
heated, it runs enough to be used in a diesel engine. It also costs a
fraction of regular 'diesel fuel' (aka "Champagne"). The engine is
started with light diesel fuel until it's running hot enough, then the
fuel mixture is gradually changed over to bunker. If the ship comes to
manoeuvering conditions, then the mixture is switched back to light
fuel. They always go back to light fuel before shutting off the engine,
too, to 'clean' the insides for the next start-up.

Now I'm wondering why we don't do this in cruising yachts, where the
engine is running constantly for days, especially considering the fuel
prices of late. All one would need is a heated holding tank and a way
of adjusting the fuel mixture. Then again, I'm not a marine engineer.
Am I missing something?

Regards,
-Max

have you guys seen Bio-diesel? make friends with the owner of the "fish
shack" and get his old fry oil. google for bio-diesel and get the
strainer/filter and engine kit. think you start the engine on regular
diesel, then switch over. exhaust might smell like french fries.

Max,
I am a marine engineer and worked on big motor ships much of my career.
The simple fact is that this would not be practical for anything less
than a megayacht with a large hired crew.

Any heavy fuel equipped ship not only has heating coils in the tank to
warn the fuel so it softens enough to be pumped out, but then also has
specialized fuel heaters that are used underway to heat the residual
(what is left over when everything they actually want is gone) fuel oil
(the current name for bunker oil) fuel to near 300F for either diesel
injection systems or atomizing burners in a stream generator (boiler).
In the engine spaces of a motor ship that runs heavy fuel is also a set
of crud catchers, strainers, filters and even centrifuges to get the
fuel clean enough to prevent damage to the injection equipment.

There is also a "burn time" issue with residual fuel oils. Back when
big engines (greater the 18'(.5m) bore were low speed engines they could
get away with it, but as they are now medium speed engines (this is
piston speed not crank speed) they are now haveing trouble there. The
story was that the low burn speed could cause conditions where the fuel
would squirt all the way across the bore to stick on the far side
without burning at all. New injection hardware has cured some of this,
but that new technology is also less crud tolerant.

Out here on the great lakes (where I last worked) they don't even bother
with trying to use heavy fuel in diesels, but a long run here is three days.

Matt Colie
Lifelong Waterman, Licensed Mariner and Perpetual Sailor

wrote:
Howdy group,
All the yachtsmen I know who run a diesel use only 'diesel fuel', which
is light and expensive. However, in the merchant navy we use bunker
fuel whenever we're going to be running the engine for a long time,
without varying RPM.

It's thicker than molasses at room temperature, but when suitably
heated, it runs enough to be used in a diesel engine. It also costs a
fraction of regular 'diesel fuel' (aka "Champagne"). The engine is
started with light diesel fuel until it's running hot enough, then the
fuel mixture is gradually changed over to bunker. If the ship comes to
manoeuvering conditions, then the mixture is switched back to light
fuel. They always go back to light fuel before shutting off the engine,
too, to 'clean' the insides for the next start-up.

Now I'm wondering why we don't do this in cruising yachts, where the
engine is running constantly for days, especially considering the fuel
prices of late. All one would need is a heated holding tank and a way
of adjusting the fuel mixture. Then again, I'm not a marine engineer.
Am I missing something?

Regards,
-Max

Re. biodiesel - there's 'biodiesel' and 'straight vegetable oil' (SVO).
biodiesel is an EPA-certified fuel that can run in an unmodified
diesel engine
http://www.biodiesel.org/resources/b...s/default.shtm. SVO
is the 'fish shack' fry oil that, when filtered, can be used in a
modified setup (heated tank, some extra fuel lines / switches).
Apparently one can brew his own biodiesel from SVO, but i imagine this
is a PITA.

Marine applications seem to be a great place for biodiesel: it's
limited availability is countered by the fact that a boat takes on a
larger amount of fuel less frequently, and that you can mix biodiesel
with petrodiesel in any proportion.

I don't know the chemical gotchas, but I'd suggest that

1) Finding Bunker C in the amounts you want and

2) avoiding the highway taxes and other costs levied on gasoline

would probably leave you spending more, not less. Particularly if your
time is worth anything.

You'd end up wiser, but grubby.

Roger

http://home.earthlink.net/~derbyrm

"Drew Dalgleish" wrote in message
...
OK I'll let all my chemistry ignorance hang out and ask. Would it be
practical to brew your own diesel by mixing bunker with regular
gasoline? Would the savings be worth it?