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Boat
Types
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THIS
SECTION
MIGHT
READ
A
LITTLE
"DRY"
AT
THE
MOMENT,
WE
WILL
ADD
MORE
INTERESTING
STUFF
AT
A
LATER
TIME,
SUCH
US
"PIRATE
INFLUENCE
ON
BOAT
DESIGNS".WE
FELT
COMPELLED
TO
ADD
THIS
INFORMATION,
SINCE
MOST
OF
OUR
GUESTS
STEP
ON
BOARD
A
BOAT
MAYBE
TWICE
A
YEAR
WITH
VERY
LITTLE
KNOWLEDGE
SUPPORTING
THEIR
DECISION
WHICH
ONE
TO
CHOOSE
EXCEPT
BY
THE
LOOKS
OF
IT
(I.E.
SLEEK
YARD
LIKE
LOOK
=
THE
BEST).
IN
OUR
OPINION
FOR
FOR
PASSAGEMAKING
OR
EXTENDED
CRUSING
THE
ROUND
BILGE
OR
SEMI
-DISPLACEMENT
HULLS
ARE
THE
FIRST
CHOICE.
PUTTING
THIS
INFORMATION
IN
CONTEXT
TO
OUR
AREA
OF
CRUISING
THE
ABOVE
TYPES
ARE
GREAT
TO
SERVICE
BURMA
WHILE
A
SEMI-PLANING
HULL
AND
PLANING
HULLS
ARE
SUITABLE
FOR
SIMILAN/SURIN
AND
SOUTHERN
AREA
OF
HIN
DAENG/HIN
MUANG:
Power
boat
hulls
are
divided
into
three
main
types
namely,
Displacement,
Semi-displacement
and
Planing
hulls,
Each
hull
type
can
have
many
subtypes
which
are
closer
to
one
or
other
end
of
the
spectrum.
Below
are
out
lines
of
the
qualities
of
the
various
types
of
powerboat
hulls.
Hulls
at
the
Displacement
end
of
the
range
were
the
first
to
be
developed
and
to
go
back
to
the
beginning
of
time;
the
original
log
canoe
and
even
the
ark
(as
far
as
we
know)
were
all
displacement
hulls.
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Heavy
Displacement: |
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These
heavy
displacement
hulls
include
such
craft
as
tugs
and
deep
sea
trawlers.
If
you
study
these
boats
in
profile
you
will
notice
that
the
stern
rises
above
the
waterline.
The
mid
section
of
the
hull
is
very
full
and
deep
in
the
water.
The
chine
and
but
tock
lines
will
reveal
the
full
bellied
shape
usually
present
in
this
type
of
hull.
The
heavy
displacement
hull
has
to
be
able
to
carry
great
loads
and
in
the
case
of
tugs,
be
able
to
get
a
great
grip
on
the
water
in
order
to
do
its
job
properly.
The"hull
speed"
of
this
type
of
vessel
is
generally
less
than
that
of
other
types.
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Medium
Displacement: |
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These
hulls
include
most
regular
work
boats,
general
fishing
boats
and
the
pleasure
boats
where
speeds
of
1.34
times
the
square
root
of
the
water
line
length
(or
less)
are
sufficient
to
fulfill
their
operating
requirements.
For
instance
let
us
consider
a
40ft/
12.19
M,
LOA.
Motor
cruiser
with
a
waterline
length
of
36ft/
10.97
M,
these
square
root
of
the
waterline
is
6
so
multiply
this
by
1.34
and
you
arrive
at
a
potential
speed
of
just
over
8
knots/
14.8
km/h.
This
is
an
economical
speed
for
this
vessel
taking
into
account
power
required
and
fuel
use
to
drive
the
vessel
at
"hull
speed".
Medium
displacement
vessels
can
only
exceed
the
1.34
rule
by
adding
excessive
amounts
of
power.
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Semi-displacement:
Semi-planing
hulls: |
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As
the
names
suggest
these
hulls
fit
neatly
in
between
the
displacement
and
the
planing
hull
types.
The
stern
of
the
Semi-displacement
hull
is
lower
and
designed
to
be
always
below
the
water.
The
hull
can
be
round
bilge
form
but
is
generally
of
the
"Hard
chine"
type.
These
hulls
have
less
fullness
than
a
full
displacement
hull.
The
chine
line
runs
aft
with
a
small
curve
from
where
it
enters
the
water
and
on
back
to
the
transom.
The
hull
sections
are
moderately
Veed.
The
semi-displacement
hull
will
out
perform
the
displacement
"Hull
Speed"
rules
and
will
accept
additional
power
and
convert
it
to
additional
speed
however
there
are
limits
to
this
benefit.
Generally
speaking
for
vessels
with
30
ft/
9.1M
to
60
ft/
18.3
M
waterline
length,
you
should
only
consider
semi-displacement
hulls
if
your
speed
requirements
do
not
exceed
12
to
18
knots.
As
with
Displacement
hulls,
Semi-displacement
hulls
can
be
driven
harder,
but
at
the
expense
of
greater
fuel
consumption
and
again
the
stern
will
tend
to
dig
in
at
higher
speeds.
Existing
semi-displacement
hulls
can
be
made
to
achieve
extra
speed
with
the
same
horsepower
by
adding
trim
tabs
or
planing
wedges
at
the
stern.
The
semi-displacement
hull
is
a
good
weight
carrier
but
it
takes
additional
power
and
fuel
to
get
the
best
out
of
an
over
weight
boat
of
this
type.
Finally
this
is
the
type
I
would
personally
choose
when
planning
to
undertake
extended
cruising,
that
is
cruising
that
regularly
involves
cruising
distances
of
over
100
miles
from
home
base.
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Planing
Hulls: |
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The
planing
hull
is
recognized
by
the
straight
run
of
the
chine
and
buttock
lines
from
amidships
aft.
The
chine
and
the
bottom
of
the
hull
V
will
generally
run
parallel
to
the
waterline.
The
V
in
section
will
generally
be
constant
from
just
aft
of
amidships
to
the
stern
the
angle
between
the
baseline
and
the
bottom
of
the
V
will
be
in
the
range
of
12
to
20
degrees
at
the
transom.
As
with
other
types
of
hulls
there
is
a
great
range
of
planing
hull
variations.
Usually
there
is
a
planing
strake
or
flat
at
the
chine
and
often
several
planing
stakes
on
the
bottom
of
the
hull.
You
will
often
hear
the
terms
"Deep
V"
or
"Moderate
V"
These
terms
are
meant
to
convey
the
amount
of
V
at
the
transom
and
in
addition
to
this
they
do
express
two
different
types
of
hull.
A
true
"Deep
V"
hull
will
have
20
to
24
degrees
of
V
at
the
transom
while
a
Moderate
V
hull
is
one
with
around
15
degrees
of
V
at
the
transom.
The
area
in
between
16
to
19
degrees
can
be
described
either
way
by
the
particular
designer
or
builder
of
the
particular
boat.
Suffice
to
say
that
a
hull
with
a
V
at
the
transom
or
20
degrees
or
over
can
be
safely
classified
as
a
deep
V
and
in
my
opinion
should
not
be
described
as
a
long
distance
or
passagemaking
cruising
powerboat.
When
deep
V
hulls
were
introduced
they
were
touted
as
the
last
word
in
planing
hull
design.
These
hulls
do
perform
well
at
high
speeds
in
rough
water,
which
is
one
reason
that
they
are
so
successful
as
racing
powerboats.
Deep
V
planing
hulls,
depending
on
the
particular
design,
can
be
driven
at
speed
in
excess
of
50
knots,
however
most
are
designed
to
cruise
at
speeds
between
30
to
35
knots.
Modern
computers
can
accurately
estimate
the
power
requirements
and
speed
expectations
of
all
hull
types
and
are
especially
helpful
in
deciding
the
power
needed
for
individual
planing
hulls.
Planing
hulls
do
not
like
being
operated
at
low
speeds;
they
throw
a
most
unfriendly
bow
wave.
For
local
and
coastal
cruising
it
is
worth
noting
that
a
planing
hull
may
allow
you
to
get
home
before
the
bad
weather
arrives.
If
your
type
of
cruising
lends
itself
to
the
advantages
of
this
type
of
hull
form,
and
if
the
disadvantages
including
high
cost
of
operation
do
not
bother
you,
then
by
all
means
consider
this
type.
In
this
case
a
moderate
V
hull
is
recommended.
On
no
account
select
a
planing
hull
if
the
area
where
you
intend
to
operate
not
suitable
for
instance
if
you're
cruising
area
is
restricted
to
low
speed
operation.
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Round
Bilge: |
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Hulls
that
are
intended
for
Passagemaking
will
often
be
round
bilge.
It
is
possible
to
design
a
semi-displacement
round
bilge
hull
but
the
S/D
type
is
more
suited
to
the
chine
hull
configuration.
Round
bilge
can
be
used
for
any
displacement
type
hull
especially
those
that
re
to
be
used
for
long
distance
voyaging.
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e-mail:
info@scuba-quest.de
S.E.A.
Charters
Co.,ltd,
Suite
13,
1st
Floor, Oliaji
Trade
Centre,
Francis
Rachel
Street
Victoria,
Mahe,
Seychelles
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