Coastal Cruiser
Steel & Aluminum
Bill of Materials
STEEL: Designed to use ordinary steel sometimes referred to
as "mild" or "low-carbon" steel. Steel of
other or special alloys is not necessary although not
necessarily unsuitable. Thickness of members, especially hull
plating, should not be increased; this will increase weight
and could affect the safety and stability of the vessel.
ALUMINUM CONSTRUCTION NOTES - IN GENERAL: It is assumed that
the builder is a qualified aluminum welder familiar with
appropriate weld types, sizes, and sequence so as to form a
strong and true vessel, with the equipment necessary to
perform work of the best quality. MIG or TIG welding is
required, using weld filler materials suited to marine use of
alloys compatible with the aluminum being welded. Aluminum
for welding must be properly prepared, and frequent testing
of welds is recommended. Plans assume construction by an
individual builder or small fabricating facility that may
have access only to more common, readily available materials,
shapes, and building processes. However, more sophisticated
alternative materials and processes may be substituted when
available and when comparable to what is shown or specified
with regard to strength, weight, and corrosion resistance. In
particular, special extrusions, if available, may be
substituted (such as at the chine) to join side and bottom
plating in lieu of the round bar shown backing this junction.
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ALUMINUM HULL MATERIAL LISTING: The following
listing is to serve as a general guide only for hull
cost estimating purposes; do not use for buying
materials without first checking the instructions and
plans for various options (such as differences due to
changes in powering methods which will vary each boat),
and to local suppliers for what material sizes may be
available. In other words, each builder must make
decisions as to how he will build the boat and use
materials, and then take off a listing to suit. Note
that if the length of the boat is varied, so too will
the material listing. Materials are listed for the
basic hull members only and do not include options,
variations, cabin, interior members, etc. Thus the
listing will vary and not all members are necessarily
included - check the plans. Only marine alloy of the
5000- or 6000-series should be used. Common acceptable
alloy designations include 5052, 5083, 5086, 5454,
5456, and 6061. For saltwater use, the 5086 is
recommended except that extruded shapes can be
6000-series. While full-length hull plating panels can
be formed by welding, single long panels are preferable
to performing this procedure. In any case, the builder
should check for plate or sheet size availability and
plan the material utilization for minimum waste. While
shorter members can always be butt welded to form long
members, a doubler plate is usually advisable behind or
on top of all such joints, lapping a considerable
distance, and being welded all around.
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ALUMINUM
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MEMBERS
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SIZE/TYPE
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AMOUNT RQD.
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Chine bars
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1/2" round bar
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50'
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Stem
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1/2" plate x 3"
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10 sq.ft.
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Keel
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1/2"
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12'
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Skeg
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1/2" to profile shown
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6 sq.ft.
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Side frames
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2-1/2" x 1-1/2" x 3/16" angle
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70'
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Bottom frames
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2-1/2" x 1-1/2" x 1/4" angle
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50'
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Frame floors
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1/4" with 1-1/2" flanges
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30 sq.ft.
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Bottom longitudinals
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1-1/2" x 1/4" flat bar
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180'
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Side longitudinals
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1-1/2" x 3/16" flat bar
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160'
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Bottom
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3/16" x 4' x 24'
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2
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Sides
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1/8" x 4' x 27'
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2
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Transom
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3/16"
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25 sq.ft.
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Bulwark
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1/8"
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62 sq.ft.
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Decking
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1/8"
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60 sq.ft.
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Deck beams
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1-1/2" x 1/4" flat bar
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18'
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Carling
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3" x 1/4" flat bar
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50'
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Pipe rails
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1-1/4" Sche. 40
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64'
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Tanks
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1/8"
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60 sq.ft.
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Strut (inboards)
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1" x 6" plate
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As rqd.
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Motor stringers
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1/4" with 5/16" flanges
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As rqd.
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STEEL CONSTRUCTION: When building from steel,
construction procedures are virtually the same as with
aluminum. However, because steel is considerably
heavier, all superstructure members from the carlin up
are made from wood and/or plywood per the Plywood
Version, plans sheets for which have been included.
Extend the carlin full length all around at least
1" above the deck. Bolt plywood cabin sides to the
outside of the carlin using sealant between the carlin
and plywood. Even still, the steel version will weigh
nearly 2000 lbs. more, causing the boat to draw between
2" and 3" more. Power should be increased by
1/3 for comparable speeds. Use the following member
sizes in place of those specified for the aluminum
version. Amounts will be similar to the Aluminum
Version.
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MEMBERS
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SIZE/TYPE
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Chine bars (opt.)
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1/2" round bar
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Stem
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3/8" plate x 3"
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Keel
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3/8" x 2"
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Skeg
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3/8" to profile shown
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Side frames
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3" x 3/16" flat bar
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Bottom frames
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3" x 1/4" flat bar
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Frame floors
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10 ga. with 1-1/2" flanges
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Bottom longitudinals
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1-1/2" x 3/16" flat bar
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Side longitudinals
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1-1/2" x 1/8" flat bar
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Bottom
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10 ga.
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Sides
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10 ga. max.
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Transom
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10 ga.
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Decking
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10 ga. max.
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Deck beams
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1-1/2" x 1/8" flat bar
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Carling
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3" x 1/8" flat bar
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Pipe rails
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1-1/4" Sche. 40
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Tanks (stainless for gasoline)
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3/32" (or comparable gage)
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Strut (inboards)
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3/4" x 6" plate
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Motor stringers
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10 ga. with 3/16" flanges
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Return
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