BOATBUILDING WITH PLYWOOD, by Glen L. Witt

CHAPTER 5 - LUMBER

SOFTWOODS

CEDAR, ALASKA
32 lbs. per cubic foot, 2.67 lbs. per board foot
Grows along the Pacific coast from Alaska to Oregon. The heartwood is bright clear yellow, while the thin layer of sapwood, which is barely visible, is a shade lighter. The wood has a fine uniform texture with low shrinkage, and is moderately strong. Heartwood is high in decay resistance, and works and finishes well.

CEDAR, ATLANTIC WHITE
(Southern white cedar, swamp cedar, juniper)
23 lbs. per cubic foot, 1.92 lbs. per board foot
The wood is soft, brittle, weak, and splits readily. However, it is low in shrinkage even though it soaks up considerable water. Because of this and its decay resistance, the wood is frequently used for conventional planking, especially in areas where the material is grown (notably along the Atlantic seaboard and Gulf states mainly in swamps), and on boats which will. be in and out of the water frequently. It has little use in plywood boat building.

CEDAR, NORTHERN WHITE
21 lbs. per cubic foot, 1.75 lbs. per board foot
Very similar to Atlantic white cedar, but because of small trees, its use is limited to small boat construction only, especially conventional planking. It is grown mostly in the Northeastern United States, and has little use in plywood boat building.

CEDAR, PORT ORFORD
30 lbs. per cubic foot, 2.5 lbs. per board foot
Grown in limited areas of Northern California and Southern Oregon, it is the preferred species of boat building cedars. Although only moderately strong, it is the strongest cedar and the heaviest before seasoning. The heartwood is light yellow to pale brown with a distinctive spicy odor. The wood is fine and uniform in texture, moderately hard, shrinks moderately, seasons well, and is very resistant to rot.

CEDAR, WESTERN RED
23 lbs. per cubic foot, 1.92 lbs. per board foot
Grown in the Pacific Northwest, the wood has narrow white sapwood and reddish-brown heartwood. It is rather soft and weak, shrinks very little, and the heartwood has good resistance to decay. The grain is uniform and straight although somewhat coarse and brittle. While often used for conventional planking, it is not highly recommended for this use. However, for veneers for use in cold molded hull planking, the material is excellent.

CYPRESS, BALD
(red cypress, yellow cypress, white cypress)
32 lbs. per cubic foot, 2.76 lbs. per board foot
Grown along the Southeastern coastal states of the United States, often in swamps. Heartwood near salt water varies from reddish to almost black, while the heartwood from farther inland is only slightly reddish or yellowish brown. Moderately strong, it is highly decay resistant, but soaks up a lot of moisture. Its primary use is in conventional planking, and therefore has little use in plywood boat building.

DOUGLAS-FIR
(yellow fir, Oregon pine)
34 lbs. per cubic foot, 2.83 lbs. per board foot
This boat building lumber comes from the coastal areas of the Pacific Northwest. It is not a true fir, thus the hyphenated name. Unseasoned green lumber is common and should be avoided. The heartwood tends to be pinkish to yellow in color, with mature growths being of straight, uniform, and dense grained. Younger trees tend to have more knots. The wood is strong, moderately hard, moderately decay resistant in the heartwood, splits relatively easily, does not bend or steam bend readily, and is fairly easy to work. Douglas-fir is sometimes used for making spars in place of Sitka spruce, and in these applications, the wood should be free of defects, well seasoned, and of vertical grain for strength.

LARCH, EASTERN
(hackmatack, tamarack)
30 lbs. per cubic foot, 2.5 lbs. per board foot
The species grows mainly in the Northern and Northeastern coastal states, but is related to western larch. The heartwood is yellowish brown, while the sapwood is nearly white. In boat building, the crooks of the trees (usually in the roots) are used to form natural knees and stems. The wood is moderately decay resistant, tough, moderately strong, and durable.

LARCH, WESTERN
39 lbs. per cubic foot, 3.25 lbs. per board foot
Grown in the Pacific Northwest and frequently harvested and shipped, with Douglas-fir. While not a common boat building lumber, there is no reason that it cannot be used if suitable stock is selected. It resembles Douglas-fir except the heartwood is russet brown instead of pinkish or reddish. It is strong (actually stronger than Douglas-fir), stiff, has moderate decay resistance, splits easily, and has moderately large shrinkage. Knots are frequent but usually tight and small.

PINE, WHITE
(Eastern white, Western white, ponderosa, & sugar pine)
25 to 28 lbs. per cubic foot, 2.08 to 2.33 lbs. per board foot
The several types of white pine are available in most of the United States, and grow in many sections of the country. While some types were once popular in boat building, their scarcity and the fact that only second growth stock is sometimes available makes most pine too weak and not durable for boat use. Decay resistance is moderate at best, and its use is best relegated to nonstructural interior joinerywork. These varieties are described to avoid confusion with the longleaf yellow pine type.

PINE, LONGLEAF YELLOW
(Southern pine)
41 lbs. per cubic foot, 3.42 lbs. per board foot
Grown in the Southern, Atlantic, and Gulf states, there are several varieties of Southern pine. However, the "longleaf" type is best for boat use. The wood is an orange to reddish brown in color, but all species are similar and difficult to differentiate. The dense heartwood is considered almost as decay resistant as white oak. The wood is strong, straight grained, and hard, however this can vary. The sapwood can be easily treated to improve its decay resistance. Often substituted for white oak.

REDWOOD
28 lbs. per cubic foot, 2.33 lbs. per board foot
Grown along the Northern California coast, the heartwood is light cherry to dark mahogany in color, while sapwood is nearly white or pale yellow. The heartwood is extremely decay resistant, but sapwood is not. The wood is fairly straight grained and free of defects, especially if heartwood. It shrinks and swells little, is easy to work, but tends to be brittle and does not hold fastenings well. The strength is moderate, it does not bend well, and has little use in plywood boat building.

SPRUCE, EASTERN
(red spruce, black spruce, white spruce)
28 lbs. per cubic foot, 2.33 lbs. per board foot
The three species, which are grown in the North and Northeastern states, have similar properties. The wood is light in color with little difference between sapwood and heartwood. It is easily worked, moderate in strength, stiffness, hardness, and toughness. It is not resistant to decay, and is used only where weight is important, and durability is not, or for non-structural work. It has little use in plywood boat building.

SPRUCE, ENGELMANN
(white spruce, Arizona spruce, silver spruce, balsam, mountain spruce)
23 lbs. per cubic foot, 1.92 lbs. per board foot
These varieties are described only to avoid confusion with the Sitka type of spruce. Grown mainly in the Rocky Mountain states, they are not suited to boat use due to softness, low strength, low resistance to decay, and lack of shock resistance. The sapwood and heartwood are hard to differentiate, and the wood is nearly white in color. It can be used in non-structural joinerywork, however, if not subjected to moisture.

SPRUCE, SITKA 28 lbs. per cubic foot, 2.33 lbs. per board foot
Grows along the Pacific Coast from Alaska to California. Because the trees grow tall, and the material is exceptionally strong for its weight, it is the ideal spar building lumber, even though rot resistance is low. The wood shrinks little and is moderately strong in bending. The heartwood is light pinkish brown and the sapwood creamy white. Where lightweight and strength are important, it is ideal.

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