Wake Free Boats
Project #1
Marine Transportation
Objectives
After completing this activity, students will be able
to:
 State the roles aerodynamics plays in boat
designs.
 Demonstrate an understanding of how and why
aerodynamics is important in boat design.
 State what a wake is and how to increase or
decrease it.
 State different designs a boat can have
 State the processes involved in creating an wake
free boat
 Create an Wake Free Boat that makes the smallest
amount of wake while being pulled across the
entire distance of the trough
Content
Boats and ships range in their designs
because of their uses. For example,
some ships simply drive through icy
water, breaking up the ice so other
ships can make it through. Where
other boats can’t drive through the
water so they drive over the water
such as swamp boats and pontoon
boats. Lets see how creative you are
in designing your own wake free boat.
Aerodynamics in Boats
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What role does Aerodynamics play in boat
design?
Answer:
Like most land vehicles aerodynamics is a
huge factor in designing boats. Some boats
are made for speed while others are made
to go over swampy areas. The most typical
ways to make a boat aerodynamic is to
start with a v-hull. Depending on the angle
of the hull the boat can have a large wake
Aerodynamics in Boat Design
Aerodynamics is the result of water friction
on the boat hull. Also the exterior finish
of the hull design will determine how fast
your boat will go. The smoother the
finish the less friction along with a
creative hull design results in a fast boat.
The way the water comes off the back of
the boat also determines the wake as
well as speed.
What is Aerodynamics?
Answer:
“Aerodynamics" is the study of
how air flows around, over, and
under an object
What is a Wake?
A wake is wave caused by the water curling
once it has passed across the boat hull. The
more area exposed to water and the speed
you drive your boat will determine how large
or small of a wake you have. Wake boarders
use these large wakes to do amazing tricks.
Wake boats use large sand bags in the back
of the boat to weigh it down so more area of
the boat is exposed to the water. Gator boats
in florida don’t have much wake at all
because of the marshes they have to drive
over.
What are different boat hull designs?
There are many different boat hull designs:
What are different boat hull designs?
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Flat-bottom boats
The one thing you can say about flat-bottom boats is that with
their large bottom area, the boat is very stable in calm weather.
Characteristically, however, the flat, broad bow area creates a
rough ride. These boats are usually limited to low horsepower
motors because they don't handle well at high speed. Flatbottom boats are greatly suited for fishing in skinny water from
the Susquehanna River to the Florida Keys, where a very
shallow draft is a must.
Early in our nautical history, boats were powered by wind or by
hand-stroked oars. Early boat designers found that boats went
faster, and were easier to steer, if the bow was pointed. They
also soon discovered that by lowering the center of gravity, the
high sail masts had better balance, and usually kept the boat
upright even in bad weather.
What are different boat hull designs?
What are different boat hull designs?
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Displacment, planing hulls
These early boats were constructed with
"displacement" hulls. This means that the hull would
push through or cruise through the water. The proper
propeller for a displacement hull is one with a lower
pitch when powered by an outboard or stern drive.
With the advent of mechanical power came boats
with "planing" hulls, which lift the boat partially out of
the water to skim on the surface. Today, it's
sometimes difficult to tell the difference between the
two, but there are slight differences. Propellers on
boats with planing hulls often are not fully
submerged, so they need to provide holding ability as
well as higher pitch and rake, because of higher topend speeds.
What are different boat hull designs?
What are different boat hull designs?
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Round-bottom hull,"V" bottoms
The "V"-bottom boat is probably the most
common hull design. Most manufacturers of
boats built today use modifications of this
design. This design offers a good ride in rough
water as the pointed bow slices forward and
the "V"-shaped bottom softens the up-anddown movement of the boat. The degree of the
angle of the "V" is called "deadrise." As the
"V" shape extends to the back of the boat, it
usually flattens out until it all but disappears
at the transom. Some "V"-bottom boats have a
flat surface at the very bottom called a "pad."
This pad allows a little more planing surface
and at the sacrifice of a little softness in the
ride, but this addition increases top speed.
What are different boat hull designs?
What are different boat hull designs?
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Tri-hull, tunnel hull
There are many boats in Pennsylvania
waters that are a distinct modification of
the "V"-bottom that are called tri-hulls
and cathedral hulls. The tri-hull boat is
the traditional "V" hull with additional
outside hulls. This design is more stable
than the "V"-bottom at rest, but it gives
a rougher ride in choppy water because
of the increased surface at the bow.
What are different boat hull designs?
What are different boat hull designs?
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Pontoon boat
Very popular in the Keystone State are
pontoon boats. And just as the name
implies, the pontoon, or deck boat, is a flat,
raised deck supported with two outer hulls
(pontoons) that are usually constructed of
aluminum. These boats combine a lot of
features of other boats. They ride very dry
because the deck is raised above the floats.
They are stable, and with the transom
mounted to the underside of the deck, they
are easy to maneuver with an outboard
motor.
Materials
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Scrap wood
Pine
Plastic wheels
Metal Rod 1/8” diameter
Wood Glue/ Hot Glue
Supplies from trays
Machines and tools
Challenge
Your grade for part 1 depends on how
close to your Printed Picture you made
your Accuracy Car. The closer it
resembles your pictures, the better your
grade will be. The more changes you
make or extra pieces you add the lower
your grade will be if they take away
from the overall shape and design.
Details are encouraged but keep them
realistic.
Challenge
Part 2 deals with the actual testing of the
vehicle. You will be at one end of the
trough. Your boat will be connected to a
string which in turn travels through a
pulley system and then to a weight at the
end. The weight will pull your boat through
the trough. The object is to construct your
boat so there is little to no wake behind
your boat. Take into account the angle the
boat will be pulled at. There are no
partners on this project; each student
must make their own vehicle.
Challenge
Your grade for part 3 is the boats when
done cannot be smaller than 8” long x 3
½” wide x 4” tall or larger than 10” long
x 4 ½” wide x 5” tall. You will be
automatically disqualified and receive a
zero if it is smaller or larger in any or all
of these dimensions. You also cannot add
weight to slow your boat down or make your
boat travel under the water. The design of the
boat is up to you but must be one of the boat
hull designs covered in the previous slides.
Challenge
Be creative on this project
and a nice design and
creative effort will only
increase your grade. You
must do all work in class
unless I give you
permission to take it home.
Good luck
Procedures
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Select the your favorite boat design that
isn’t too challenging to make
Research it on the computer finding
pictures or just draw it the best you can
with a ruler and dimensions
Cut your pine wood, wood glue it
together
Construct your boat
Practice your boat as often as possible
making any changes needed
Evaluation
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Printed Pictures are a separate grade
worth 100 points
There is a reflective worksheet that
counts as a separate grade of 100
points
See Attached Rubric
Remember that there is no fooling
around in the lab
Always wear your safety glasses or you
will be removed from class
Evaluation
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Project stayed within the required
dimensions
100 Points
Project looks like printed or drawn
pictures with minimal changes
Project made minimal wake and
traveled the entire distance of the
trough
Student shows above average effort
Student shows above average safety
skills
Evaluation
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Project stayed within the required
dimensions
Project looks like printed or drawn
pictures with moderate changes
75 points
Project made moderate wake and
traveled the entire distance of the
trough
Student shows above average effort
Student shows above average safety
skills
Evaluation
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Project stayed within the
required dimensions
Project looks like printed or
drawn pictures with very
noticable changes
50 points
Project made excessive wake and
traveled the entire distance of
the trough
Student shows above average
effort
Student shows above average
safety skills
Evaluation
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Project did not stay within the
required dimensions
0 points
Project does not look like printed
or drawn pictures
Project made an extreme wake
and/or traveled the entire
distance of the trough
Student showed no effort
Student showed no safety skills