Types of Wood for Marine Use

Marine lumber is picked for its rot-resistant qualities, durability and grain texture.

Thousands of species of wood grow throughout the world. Boat building requires a certain wood that has characteristics suitable for a marine environment. Boat building wood can not be too soft, brittle, decay-prone, light and airy, or too short to fabricate necessary lengths for keels and planking. Over generations of trial and error, many wood species have proven their worth by standing the test of time. Dense hardwoods, and some softwoods, have the most applications in boat-building.

Apitong

Apitong weighs 44 pounds per cubic foot, and 3.67 pounds per board foot. It comes from the Philippines, Malaysia and Indonesia. It has a creamy yellow, gray or white sapwood, with a typically straight grain. Apitong dries slowly and resists decay moderately. It has excellent strength, able to hold fasteners well and frequently replaces white oak, yet remains less durable than white oak.

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White Ash

White ash weighs 42 pounds a cubic foot, with 3.5 pounds per board foot. White ash hails mainly from the Easter United States. It has a brown heartwood, with a sapwood that approaches white in color. It possesses a straight grain, holds its strength well and lends itself well to steam bending. It has low-decay resistance qualities, limiting its use to joinery, small-boat framework, tillers and oars.

Greenheart

Greenheart has a very dense core, weighing 61 pounds per cubic foot and 5.08 pounds per board foot. Greenheart comes from South America, Guiana and it appears in the West Indies. Its properties make it decay-resistant to moisture and even some marine boring animals. It has stiff qualities, making it once famous in European boat-building circles. Its colors range from greenish-yellow to deep brown or purple. It has a very dense and heavy weight that makes it strong and shock-resistant, but can also add unwanted weight.

Iroko

Iroko weighs in at 40 pounds a cubic foot and 3.33 pounds per board foot. Iroko mainly comes from Africa and resembles teak, but weaker in structure. It has moderate decay and marine borer resistance. It can be easy to work with, comes in a green or yellow heartwood, but changes color to brown upon sunlight exposure. Europe has favored Iroko as a boat-building material for generations.

Lignumvitae

Lignumvitae weighs in at the heaviest of woods known at 76 pounds per cubic foot and 6.33 pounds for each board foot. It grows in the West Indies and Central America. The wood contains naturally occurring oil pockets, which makes it ideal for rudder shaft bearings, worm shoes and keels, with some rubbing strake applications. The heartwood ranges from blue to nearly black, with a cream sapwood. It resists decay and marine borers extremely well, possessing a high stress and crush strength.

African Mahogany

At 32 pounds per cubic foot and 2.67 pounds per board foot, African mahogany resembles genuine mahogany, only it has colors that range from pink to reddish brown. It does not work nearly as easily as genuine mahogany, but resists decay and has good lasting qualities. The wood resists shrinkage well and endures seasonal changes without deformation.

Genuine Mahogany

Although it sometimes takes on the name of Mexican Mahogany, the tree grows in South America, Central America and parts of the West Indies and Florida. The heartwood can vary considerably, depending upon its region of origin, but it usually contains reddish or brown pigments, with a cream-colored sap. It has excellent decay resistance, weathers well and has a moderate shrinkage rate. The Central American species holds the most value for boat-building.

White Oak

White oak can be fairly dense at 47 pounds per cubic foot, and nearly four pounds per board foot. White oak, considered an Eastern wood, has a weaker structure than red oak. It rots easily unless treated. The heartwood appears tan to light brown. In its green condition, white oaks steam and bend easily. It still remains hard to work with, though, and needs very sharp cutting tools to fashion it. Some adhesives do not work well on the wood when submerged in water, due to the wood's high acid content.

Teak

Teak weighs in at 43 pounds per cubic foot, and takes up 3.58 pounds per board foot. Called the most decay-resistant wood in the world, it still has a slight problem with some marine borer adhesion. Teak grows in Thailand, the East Indies and Burma. The sapwood can be white to brown. The grain runs straight and the wood texture has a coarse or oily feel to it. The wood can be brittle, and dulls cutting tools. It has common uses for decking, salons, joinery and cabinet structures.

Cedar

Port Orford cedar weighs 30 pounds per cubic foot, and 2.5 pounds per board foot. Considered a softwood, Cedar comes from Southern Oregon and parts of Northern California. The Port Orford variety of cedar has the most uses in boat-building than any other cedar, due to its fine grain and strength. It has a light yellow to brown heartwood, and exudes a spicy odor. It has excellent rot resistance and holds up to moderate standards in all other characteristics.

References

• Glen-L.: Wood and Plywood FAQ's
• Glen-L.: Lumber Species for Boat Building
• CLC Boats: Solid Wood For Boat Building