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Teacher
Edition Contents
Skill,
Tools, & Craftsmanship
Cutting
& Drying Fish
Sharpening
Nails,
Pegs, & Lashings
Falling
Trees &
Small-Scale
Logging
Guns
Chainsaw
Clutch & Chain
Ice
Pick
Shelters
Wood
Stoves
Wall
Tents
Steambaths
Insulation
& Vapor Barriers
Gas
Lamps & Gas Stoves
Travel
Piloting
A Boat
Boat
Design
Magnetos
& Spark Plugs
Carburetors
Compression
Outboard
Motor Lower Unit
Outboard
Motor Cooling System
Dogsleds
Snowmachine
Tracks
Snowmachine
Clutch
Snowshoes
Winter
Trails
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Activities
- Look at the different boats in the village. Identify the planing
boats and displacement boats. Some fishing boats are a compromise
between the two.
- What is the average length and width of the boats in your village?
What is the average height of the sides in the middle of the boat?
What is the average angle outward of the sides, in both the middle
and back? What is the average angle backward of the transom?
- Ask a local boat builder what happens if the transom doesn’t
have enough angle.
The motor can’t get far enough under the boat. It is
tilted out, and thus pushes the back end down and the front of
the boat up. If the transom has too much angle, the motor can
always be tilted out with the tilt pins.
- What are the different materials used in boat construction
in your village?
- How does the style of boat in your village compare with those
in the description in the above text? Are they “downriver
boats,” “upriver boats,” “ocean boats”
or a combination, or something different?
- Talk with a local boat builder about boat design. Does he agree
or disagree with some of the thoughts in the above text?
- Look at a canoe if one is available. Are the turns and curves
gradual? Compare this with a planing boat. Which would you rather
paddle or pole upstream?
- Ask the oldtimers about shooting out of a canoe. What precautions
must be taken?
- Try poling a planing boat upstream in swift water. Paddle or
pole a canoe in the same place. Compare the effort.
- Compare the bottoms of the boats in your village. Feel them
if you can. How rough or smooth are they? If they are rough, how
did they get that way? How would you reduce the friction on each
one? Do boats in your area need paints with copper compounds to
prevent organic growth?
- Students should slap the surface of a small body of water with
their hand, a board or paddle. Increase the speed with which it
is slapped. Notice that it seems to become “solid” the
faster it is slapped. How does this apply to a planing boat.
- Carve a displacement or planing boat from soap or cottonwood
bark.
- Ask oldtimers how they hauled big loads long ago. How is that
different from today?
They had long slim displacement boats with much smaller motors.
- Draw an upriver boat. Draw a downriver boat. Which do you prefer?
- Ask oldtimers how they built canoes or kayaks. What are the
effects of changing width? Length? Did they put a rocker1 in the
bottom? How high were the sides? What were the problems they had
with materials? Today we weld and use synthetic caulking. How
did they fix leaks long ago?
- Ask around the village to find out the gas consumption of the
new four-cycle outboards. How many gallons per hour for each horsepower
rating? Divide the horsepower by the gallons to find the ratio.
Compare this with the gas consumption of newer two-cycle motors.
- Compare the difference in purchase price of a two-cycle and
a four-cycle outboard. The four-cycles are more expensive. What
is the price of gas in your community? Can you figure how many
gallons of gas a four-cycle would have to burn to pay for the
difference in purchase price? This isn’t a simple problem.
You will probably have to do it as a class, but it is one everyone
must take into account when buying a motor.
My calculations say that by the time the four cycle engine
has paid for itself in the gas it has saved, it will be worn out.
I don’t think there is much difference in the long run, but
that is for this area.
- Ask in your village how much the boats cost. Compare the cost
of the different kinds of boats with each other. Ask people how
long each kind of boat lasts (plywood, fiberglass, aluminum etc).
In the long run, what is the cheapest kind of boat? Is it also
the most useful kind of boat? Do people still make their own boats?
Why? Is it because commercial boats aren’t designed properly
for your location?
Student Response
- What are the two different kinds of boats?
Planing and displacement
- Which of these two kinds of boats is better for carrying a
big load with a small motor?
Displacement
- Which of these two kinds of boats is better for running around
with a light load?
Planing
- What is the most important thing to remember in designing a
displacement boat?
Gentle, gradual curves to push the water out of the way gradually.
- A planing boat is better when it is wide or slim?
Wide
- Which planing boat will get on step faster, one with a flat
bottom or one with a V bottom?
Flat
- Which planing boat will give a smoother ride in rough water,
one with a flat bottom or one with a V bottom?
V bottom
- Which is better for your location? Why?
Answers will vary.
- What are the advantages of high sides on a boat? What are the
disadvantages?
Advantages: safer in waves, water can’t come in the boat.
Disadvantages: high sides tend to blow around in the wind. It
is harder to get in and out of a boat with high sides.
- What is the force called that slows a boat with a rough bottom?
How is this remedied with a wooden boat?
Friction. Sand or burn the rough material off with a blow torch
and paint it.
- There are four common materials used in boat construction. List
them and one advantage and one disadvantage of each.
Wood: Inexpensive, strong, repairable. Heavy, not durable in
the ice, knots fall out, rot.
Plywood: Same advantages and disadvantages as wood, but leak less.
Marine plywood is expensive.
Aluminum: Doesn’t rot or rust, light, unharmed by ice, easy
to drag over ice, lasts a long time. Owner can’t design and
build his own, noisy for hunting, owner can’t repair it,
some have leaky rivets. Eventually they crack in the transom and
in the front where the boat touches the beach.
Fiberglass: Unharmed by running in the ice. Slides well on ice,
low friction with water, strong and low maintenance. Owners can
do repairs. Owner can’t design his own, heavy, age in sunlight,
shipping cost is high.
Math
- One boat travels 20 miles upstream in a swift river where the
average current is 10 mph. The boat’s speed relative to the
water is 20 mph. The boat makes a round trip. Another identical
boat and motor travels 40 miles on a lake where there is no current.
There is no wind acting on either boat. Question: Do they both
make the trip in the same time, or is there a difference? If there
is a difference, why?
- Plywood costs $35 a sheet landed in the village. Screws to
build a boat are $4.50 a pound. Paint is $22.5 a gallon. The lumber
to build the ribs and other parts is $1.25 a board foot. Five
gallons of fiberglass resin flown into the village is $89. The
fiberglass cloth is $3.00 a linear foot. How much would it cost
to build a boat 24’ long? The boat is 4’ wide and will
take six sheets of plywood. It will require 4 pounds of screws
and three and a half gallons of paint (only available in gallons.)
Add 10% for incidental expenses like calking, glue, paint brushes
etc. An aluminum boat is $3,200 landed in the village. Which is
cheaper? Considering that an aluminum boat lasts twice as long,
which is cheaper?
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