Typical Styles of Bow
Sections & Hulls
MODEL
-
MODIFIED
-
SPOONBILL &
SCOW = BOW'S
All shipbuilders have particular styles, traits
and characteristics, setting them apart. So you can study a
particular shipyards work and instantly see their characteristics after
some study. But remember, all shipyards can marry ( join together ),
virtually any style of "Bow Design", to the rest of a hull, to suit
whatever a buyer wants. This means a hull basically consists of Three
- Sections = Bow /
Mid-ship & Stern and each
can be built in various styles and shapes. Yet married together with
only a few changes made, to accomplish the job. Here shipyard
traits are usually easily recognized, once you understand the
shipbuilders style and how they do things. "Basically its like the
difference between "Fords & Chevy's!" ... After a while you can easily
spot and tell the difference at glance.
Whether an entire vessel, or just structures and they're shapes, buyer's
often want something different from a builder's norms. REMEMBER ....
Things sometimes can be puzzling, but the overall look of a vessel
usually shows traits of who built it if you study the design closely.
Today, thanks to computer 3-D drafting & design software, high tech
construction methods can build structures at one shipyard, while another
shipyard someplace else, builds the hull or other sections. Then they
simply bring all the parts together, using heavy lift -cranes, which is
called "Modular Pre-fabrication" and weld them together. Its
commonplace at many shipyards - today, as well as faster and it reduces
costs. But also insures everything fits perfectly upon assembly is
done, right down to where the wiring goes. Here, everything within
each section, must be pre-installed in order to make the modular system
of building - work.
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Drawing to Enlarge
A "MODEL" BOW
= Can be used on any size or type of hull, no
matter its width or drafts and lengths. However, its Deep - V shape,
is not always continued further back into the hull's = mid-ships or
stern sections. Why? .... Because a V- shaped hull, to easily tips
over, if the hull goes aground and it would most likely = roll-over &
sink. Model Bows are generally married into a more typical - Flat
Bottom style of Mid - Hull Section. Or this type of bow section can
be used on vessels designed to work only in certain areas, where its
deeper v- drafts won't be effected by dangers of running aground. And
this is a favored style of towboat hull designs, for Southern Gulf -
Shipyards. Such Gulf shipyards produce what is commonly called a
"Cajun Towboat", for their unique styles, which use traits from Tugboats
- as a concept to create a combination Tug & River Workboat.
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THE MODIFIED BOW =
Is used generally on Mid-size to Large Hull = 90' to 200' lengths in
"Line & Long Haul" class vessel designs. Note its" Hard Chine" =
Slanted Hull Sides, which pass more water under the slanted
hull-sides, to the stern for better Thrust & Steering.. This style of
bow, or overall hull is a standard design used by Jeff boat, "The Worlds
Largest Inland River Shipbuilder", located on the Ohio River! They
prefer to build this hull design, but also build anything else buyer's
wants, but they highly recommend their own style as any shipyard does.
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THE SPOONBILL BOW
= Is found more commonly on older
vessels, usually built prior to the 1960's on larger hulls = Trip Boats
/ Line & Long Haul - towboats. But has been used on smaller boats too,
and gives the hull a somewhat rounded shape at its corners. And
avoids the problem of the hull - easily being rolled over, if it goes
aground, since only the hulls sides are rounded at their edges - Bow &
Mid Ship points.
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THE SCOW BOW
= Is used on all types of towboats - Small & Large. Class or
size of the boat, makes little difference to this design, being the
simplest to build. Note the Scow Bow - simple shapes, which are
formed into rounded edges at its lower - hull sides. The only problem
with this design, deals with keeping its bilges - dry, to the hulls -
flat bottom shape, making it difficult to keep dry, unlike a vessel with
a slightly rounded hull bottom. With the bilges - dry, its stable =
as a Rock, however if a few inches of water are allowed to accumulate in
the bilge, it becomes a unstable and easily tips-over and sinks.
Probably the most often used design, for smaller vessels as well as
barges, its faults are small, compared to its success. Dravo
Shipyard of Neville Island PA. ( now out of business ), used this style
of hull, on their large boats. And their smaller partner company -
Steel Ship, also built such hulls, and was once located at Pine Bluff
Ark and built many smaller Tenders & Trip boats, before it closed.
FINAL COMMENTS ....... As I said, there
are many ways to marry a Bow, to the rest of a hull, regardless of its
shape. And some very unique shipyard styles have appeared, like
during the early 40's to 60's when towboats were commonly given what
was called a "Sway-Back" style of hull, typical of their ole steamboat
days in overall hull shapes. This just means the builder gave the
hull a slight amount of curve to its main deck, and amidships section
was lower to the waterlines, then the Bow or Stern sections were. ....
Sorta low in the middle and High on both ends! And a "Swayback Hull,
if it took on water in the bilge, continued to stay stable because the
water always went to the hulls - lowest points. And there - it could
easily be pumped off, without causing the boat to become - unstable.
However, on flat bottom hulls, you must keep a watch on the bilge's, to
always keep them pumped - dry. Because of the flat hull design,
water spreads throughout the hull and can, if the boat is turned hard,
cause the water to rush to the lower side and cause it to take on more
water. And you can imagine what happens - NEXT, when that Happens!
Typical - Stern Designs
Ramped, Step-Up, Sloped
& Flat- Deck
The Stern Section - can be built with or without - Tunnels, which
provide deeper areas under the stern, for the steering and propulsion
systems. A tunnel hull allows enlarged props or wheels to be installed,
which naturally increases thrust & power.. The basic's of how
shipyards use certain styles or characteristics in hulls, sometimes can
be confusing. And some hull traits are common to only one shipyard
and easily recognized, by the trained eye. While other designs may
not easily show exactly whom built them, as far as basic
characteristic's - are concerned. Here, sometimes you have to look at
the vessels history, in order to see what was changed or has been
modified by past ownership, because these towboats - Never Stay The
Same! Damaged, or in need of rebuilding, often whole sections of the
vessel may have been changed or altered, which removes original
characteristics, and here - the Vessels Records, which can be located in
books like the "IRR" = Inland River Record Book, report on the Vessels
past. So you can determine what has been changed, improved or
removed, if you know where to look!
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Types of - Stern Sections
( Top to Bottom ) NOTE .... The Three Top Drawings
... show stern sections = equipped with Tunnels ... Which
allow the use of larger Props = Wheels, to increase horsepower and
thrust. Especially done with towboats equipped with "Kort Nozzles",
which are embedded up into the Tunnel - stern, to protect them further
.... BOTTOM
DRAWING = shows a stern that "Is Not Equipped" with a Tunnel,
forcing the use of smaller - Props = Wheels. Stern Hull sections =
like this, are built typically in smaller Utility & Tender class boats,
that aren't usually over 50' length and is the most basic style used
today.
The Mid-section of the hull, is the deepest part, where most of the
inner systems that run the vessel, are located. From the Main
Engines, Fuel Tanks, Water Tanks, Sewage Systems, Used Oil and Bilge
holding tanks. Its usually all fitted into the overall hull, but most
of it is located in the deepest part of this sections designs. The
Fuel Tanks, take up most of the space, with the main engines the second
largest items. And this section of the hull, may be designed
differently at either end, depending upon the style of the Bow or Stern
Sections, that are married to It.
Hulls, Rudders, Kort's &
Keel Coolers
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The Stern - Section of a Line Hauler
As its built and laid - Upside Down! Note the "Tunnel Hull" design
that includes the "Kort Nozzles", installed into the hulls configuration
on this boat. This is an older "Dravo Ship" design, of about 5,000
horsepower, judging by the hull diameters and the size of the kort's.
The size of the Kort's, indicate the Wheels = a term for Props, from
steamboat days. Will have about a 10' diameter, once they installed
under this 12' overall drafted hull. ( Photo by Joe E. Brown )
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The
Business End
Showing a closer view of the Kort Nozzle
and Flanking & Stern Rudder steering.. Note the "Brace Ribs" along the
sides of the rudders! These rudders were designed so that their -
lower sections, can break off, if they are struck by an object. This
way - the boat may lose only a portion of a rudder and steering ability,
yet still able to continue until later repairs can be made later. Note
also - Water around this area of the stern, is only inches from the
surface along the Hull Sides. The notice how the Wheel and Kort, is
actually embedded up into the tunnel hull, allowing an increase sized
system, for better thrust, without lowering the props to dangerous
points. This further protects the steering systems from damage, which
the hull takes the worst of any abused punishment, usually, as a
rule. (
Photo by Joe E. Brown )
Remember -
The theory of towboat
designs, are unlike any other. These boats can't take anything for
granted, like having plenty of "Deep Water" under their Hull, unlike
others that work in deep water!
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Photo to Enlarge
Hull Coolers
- also called "Skin or Keel
Coolers", which are "Radiators" of the boats main engines and/or its
Auxiliary Engines. Mounted along the hull- sides or along the bottom
of the hull, where they can cool the engines with water that passes
through them. Note in this photo, how they run the entire length of
the hulls - deeper mid section, about 2 1/2 feet from the top of the
main deck, or so-called "Boiler Deck" They will be - just under the
surface, or waterline of the hull, once its afloat. And Both Sides =
Port & Starboard have "Coolers", including smaller systems for the
Auxiliary Engines .... ( Photo by Joe E. Brown )
How
Modern Towboats - Use Duel Steering
Drawing Of A Typical Line hauler - with a
Modified Hull, "Twin Screws" & Duel Steering!
Stern
Bow
Watch The Rudders -
"MOVE!"
The Drawings Above, Show How "Duel Steering - WORKS!"
A proven design, 1st
applied to early stern
wheel - steamboats, when they were converted to push barges. And
became a standard for all towboats,
no matter - Hull Size,
Class, Horsepower, or number of Engines. Its even used on "Single
Screw" towboats too, and the usual rule of thumb says - "A Boat will
normally always = a total of 3 rudders = Per Drive Shaft. Meaning a
typical Twin Screw = towboat, will have a total of ( 6 Rudders = In All
), or 2 - Stern Rudders and 4 - Flanking Rudders. And combined
with its engine - thrust ( In either direction ), duel steering provides
"ALL DIRECTION - STEERING Abilities .... Even while pushing 50+ barges!
Carrying a total of ( 6 Rudders - In All
- On A Twin Screw ), means these two systems are "Separate" from one
another and operate by their own set of Hand Tiller Controls.
This just means the Two - Stern Rudders
are coupled together and Steer as one system.
Totally independent of the Flanking
Rudder system, meaning the vessels ( 4 )
Flanking Rudders, are
all - coupled together to steer as one steering system also.
Remember, both systems - work independently of the other, so
a pilot can steer - In Either Direction, which is something not normally
found on most workboats & ships. But these vessels must battle high
currents on narrow / very shallow inland rivers, where cross winds in
tight / close-in maneuvers within such narrow channels., limits the
space you have to a maneuver. And maneuvering a vessel handling a
1/4+ mile long tow of barges, in such narrow - shallow waters, needs
"Optimum Steering Abilities."
Thus making - The Towboat, the 1st to use
Duel Steering .... And the most highly maneuverable vessels - IN THE
WORLD, using the simplest of steering methods - Duel Rudder Systems!
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Last Updated On
06/29/23 .
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