Deck Fill Protection Device
Manufactured by Marsh Marine...Tank Cleaning Professionals
“Our experience is your protection since 1966”
By Marshall Solomon
M
uch
of
my
business
with
Marsh
Marine
is
cleaning
diesel
fuel
and
tanks,
a
process
that
has
become
known
as
fuel
polishing.
Performing
this
service
over
years
has
brought
me
into
contact
with
a
variety
of
fuel
related
problems
and
the
reality
that
many
boat
owners
know
very
little
about
diesel
fuel.
There
are
many
misconceptions,
false
products,
and
a
general
take-it-for-granted
attitude
about
this
precious
substance.
So
let’s
pull the hatches off and really get down to understanding diesel fuel inside and out. First some basic fuel facts:
D
iesel
fuel
is
a
blend
of
a
number
of
hydrocarbon
compounds
derived
from
refining
crude
oil.
Its
sister
fuels
include
Kerosene
and
Number
2
Heating
Oil.
At
one
time
oil
refiners
created
diesel
fuel
from
crude
oil
through
a
heating
and
condensing
process
called
fractional
distillation
which
separated
the
various
products
like
kerosene,
gasoline,
naphtha,
waxes,
and
others
based
upon
their
different
boiling
points.
This
older
process
produced
an
extremely
fine
product
that
was
quite
stable.
As
technology
improved
and
demand
increased,
petroleum
chemists
found
they
could
boost
production
using
chemical
reactions
in
the
presence
of
various
catalysts
to
break
the
complex
organic
molecules
of
crude
oil
into
simpler
molecular
compounds
(products).
These
various
methods
of
breaking
the
carbon-carbon
bonds
are
collectively
called
Cracking.
Today,
cracking
is
the
standard
process
of
refining
crude
oil.
As
they
say,
however,
there
is
no
free
lunch,
and
today’s
diesel
fuel
is
not as stable as it once was. Keep this important fact in mind as we move along with the discussion.
D
iesel
fuel
ignites
at
a
higher
temperature
than
gasoline.
That
is
to
say,
a
spark
will
not
cause
it
to
flame
like
gas.
In
a
diesel
engine,
ignition
of
the
fuel
is
caused
by
the
heat
of
compression
within
the
cylinder
and
not
from
a
spark
plug.
There
is
almost
twice
the
energy
stored
within
a
gallon
of
diesel
as
compared
to
a
gallon
of
gasoline.
This
is
one
reason
why
diesel
engines
are
considered
more
economical
to
operate.
Gasoline
is
rated
by
its
Octane
number,
like
87,
91,
or
93.
Diesel
fuel
is
rated
by
its
Cetane
number
which
is
usually
40
to
50.
This
number
is
a
measure
of
the
ease
with
which
the
fuel
is
ignited
in
your
engine.
Your
engine
manufacturer
determines
the
minimum
cetane
level
for
the
type
of
service
the
engine
is
intended.
Most
manufacturers
recommend
diesel
fuel
with
a
cetane
number
of
at
least
40,
and
most
diesel
fuels
sold
by
reputable
dealers
meet
or
exceed
this
requirement.
Diesel
fuel
with
a
cetane
of
40
to
45
is
considered
regular
while
45
to
50
is
a
premium
grade.
Now,
before
you
run
out
and
buy
any
of
the
cetane
boosting
additives,
know
that
increasing
the
cetane
higher
than
required
for
your
engine
does
not
materially
improve
engine
efficiency
or
operation.
Cetane
level
is
seldom
a
problem.
Diesel
is
heavier
than
gasoline
but
lighter
than
water.
This
means
water,
if
present,
will
be
found
beneath
the
diesel
fuel.
Marine
diesel
or
more
correctly
off
road
diesel
is
usually
red
in
color
while
road
diesel
is
usually
amber
colored.
The
coloring
is
added
so
the
tax
police
can
collect
road
use
taxes
which
off
road
users
don’t
pay.
I
might
add
here
that
there
is
no
certain
relationship
between
fuel
color
and
fuel
quality
since
color
varies
with
crude
source,
refinery
methods,
and
dyes
used.
However,
if
the
fuel
color
darkens appreciably during storage, this could indicate oxidation, contamination, or degradation.