Your Guide To Marine Woods

Wood may no longer rule modern boatbuilding, but it still delivers time-tested benefits.

Back in the days when wooden boatbuilding was as much art as craft, builders took great care when choosing the proper type of wood. A good marine wood possesses a balance of strength, weight, and durability. Resistance to rot and insects are also desirable attributes, as is sustainability (with regard to renewability). Workability is also important. A wood that’s extremely dense is hard on tools and difficult to work with, while one that’s too heavy can affect vessel performance.

Woods less suited for the marine environment, such as red oak or yellow pine (a generic term that encompasses multiple species), are softer, weaker, less durable, and more prone to water intrusion and rot.

Selecting the best lumber available is also critical. Heartwood, the older, darker, and harder wood found at the center of the trunk, is the best of the tree. On the other hand, sapwood (the outer, lighter-colored, living part of a tree that transports water and nutrients) should be avoided for marine applications: It is less dense, weaker, and more prone to rot.

In today’s world of rushed expectations and globalized supply sources, the selection of wood available at big box stores will often be lacking. Construction-grade lumber and plywood are not acceptable for boat construction (or marine use in general) from both a quality standpoint and because they are not properly dried. Good marine-grade wood, on the other hand, is properly dried and free of knots and other structural defects.

Here’s a primer on typical woods used in modern boatbuilding as well as their benefits, uses, tips for working with them, and maintenance considerations.

TEAK

Often considered the “gold standard” of marine hardwood, no other wood is more universally associated with boats than teak. It’s not an idle opinion, and teak enjoys it due to a number of attributes such as strength, durability, and water-resistance.

The teak tree (Tectona grandis) is native to the Southeast Asian countries of Myanmar, Thailand, Laos, and India, although it’s now also cultivated on plantations in Africa, Indonesia, and South America.

Why it’s good: The natural oil found in teak provides protection against rot and insects, while its high silica content provides excellent antislip properties as well as dimensional stability regardless of weather or climate. No wood can take the constant exposure to water, sun, or abuse better than teak. Although hard and dense, teak is nonetheless easy to work, even with hand tools.

Uses: Teak’s close grain makes it ideal for applications requiring strength and close tolerance fits including hull planking, decking, cabinetry, and interior trim. Teak lends itself well to most any boating accessory: handrails, trim and deck gratings, cockpit tables, dish racks, binocular holders, and more.

Maintenance: The beauty of teak is that its natural oil makes it essentially maintenance-free, meaning you can put as much or as little effort into maintaining it as desired. Due to its resistance to rot, teak maintenance is appearance-driven rather than for preservation.

Those who like the natural color of teak will need to periodically clean and apply one of the various oils or sealants available on the market. If left to its own devices, exterior teak will gradually take on a silver-gray patina that many find equally appealing. Maintenance for this natural look is merely an occasional light cleaning with a soft bristle brush and rinse.

Working with teak:

• Use carbide tipped blades when cutting. Teak will dull blades more rapidly due to its natural oils and high silica content.
• Use a high-speed drill and bit when drilling to ensure a clean hole.
• Due to oil in the fibers, teak dust is slightly tacky. This means you’ll need to change sandpaper more frequently when sanding.
• For gluing, epoxy and polyurethane glue work well, as do glues such as Gorilla Glue and Titebond II or III. For clean, freshly cut joints, it’s fine to apply the epoxy or glue directly. If the wood feels oily, scrub with acetone and let dry prior to gluing.

Mahogany

No other marine wood surpasses the “feel” of boating luxury and timeless elegance than the rich, reddish-brown hue of mahogany. Nothing exemplifies this more than the classic era of mahogany motor launches and runabouts by builders such as Chris-Craft, Gar Wood, and Hacker-Craft from the 1920s to 1960s.

Mahogany comes from trees native to the tropical regions of Central and South America, with the most famous varieties being Swietenia macrophylla (Honduran or big-leaf mahogany) and Swietenia mahagoni (Cuban or West Indian mahogany). Of these, Honduran mahogany is what most consider to be genuine or true mahogany.

Why it’s good: Mahogany is prized by boatbuilders due to its strength and rot-resistance. Although exceptionally solid and dense (it’s primarily heartwood), mahogany is also buoyant and highly resistant to shrinkage caused by losing moisture content. That is due to its nearly 1–1 ratio of radial shrinkage (perpendicular to the growth rings) to tangential shrinkage (around the growth rings). Despite its density, mahogany is fine-textured and exceptionally easy to work with both hand and machine tools.

Uses: In addition to structural components such as frames and planking, the beauty of mahogany makes it desirable for most any boating project, from vessel accent trim to cup holders and tables.

Maintenance: Unlike teak, mahogany will look better and last longer when varnished or treated with a wax or sealant. Opinions vary as to which is the better approach, however, in general, if you want a rich, vibrant finish, multiple coats of varnish are the best bet. If ease of application and maintenance are more important than a glossy finish, sealants offer a viable option.

Working with mahogany:

• Use sharp tools and blades to prevent tear-out, especially when working with the grain.
• All woodworking glues work well with mahogany, but use a waterproof glue for outdoor projects.
• Predrilling for screws is recommended, especially in finely detailed pieces, to prevent splitting.

Iroko

Native to the west coast of tropical Africa, the iroko tree (Milicia excelsa) is a hardwood tree also known as “African teak.” Iroko heartwood is yellow to golden or medium brown in appearance, while the sapwood is pale yellow.

Why it’s good: Iroko is easy to work by hand or with woodworking tools. Thanks to its naturally oily and resinous heartwood, it is highly durable and resistant to moisture and rot – ideal traits for the marine environment.

Uses: A dense, strong wood, iroko is suitable for structural elements such as framing and keels. Its resistance to impact and wear makes it a good choice for planking as well as rubbing strakes and gunwales. Iroko wood’s natural oils and durability make it an attractive alternative to teak for decking, cockpit gratings, and the like – particularly as it is a sustainable timber and less expensive.

Maintenance: Like teak and garapa, iroko has limited maintenance requirements that are primarily cosmetic-driven. Freshly machined iroko has a golden-yellow color, which needs to be sealed to maintain. If left to the elements, it will slowly weather to a silvery-gray patina, similar to teak.

Working with iroko:

• Iroko cuts well and isn’t prone to splintering. However, like teak, its high silicon content means you’ll have to sharpen tools more frequently.
• Iroko takes screws and bolts well, however, in some cases, predrilling holes may be a good precaution to avoid splitting.
• When cutting or planing iroko, its interlocking grain can be an issue, causing a saw or planer to catch and tear out sizable chunks of wood. To prevent this, try to identify and avoid interlocking grains.
• Like teak and garapa, epoxy and polyurethane glue work well, as do Gorilla Glue and Titebond II or III. For clean, freshly cut joints, you can directly apply the epoxy or glue. If the wood feels oily, scrub with acetone and let dry prior to gluing.