Thursday, May 7

Good Wood for our Boat

Let it be sung in the streets that I love wood.  To me it is warm, strong, firm, hard to bend, my protection, and my shelter,  When we were searching for a sailboat, I love the all-wood deck sailboats like the Cheoy Lee.  JT reminded me of all the maintenance, work, cost, and possible leaks that could come from wood decks.  We found a boat with lots of wood inside and a little wood outside that we must yearly do maintenance on in the Texas heat and humidity.

A new sailor arrived the other day on a Cheoy Lee but it was missing something.  Its beautiful teak deck.  They had removed 1,700 screws because the boat leaked.  The boat looked great without it, but oh it is still sad to me.

Many of our fellow sailors are redoing the interior of their boats, and I am all too eager to check out their work.  Some are using spanish-cedar (which was new to me), white oak, teak, or cherry in their remodeling.  This got me thinking about which wood is good on the boat.  Here is the research that I found on wood-database.com and growthringsinnovation.com about the woods for boats.  Notice the specific gravity and how that relates to the rot resistance since many fiberglass deck have balsa wood between the fiberglass.

In Houston, Texas area we have found teak plywood for hatches for another boat but had to order long teak boards to build teak eyebrows
Spanish-Cedar (not a true cedar but in the mahogany family, Meliaceae)
Cedrela odorata L
Specific gravity is .38
Ring-porous to diffuse porous, found in Caribbean and Central America, pinkish to red-brown color, grain is strain or shallowly interlocked with medium texture, mineral deposits of red gum are occasionally present, durable to decay resistance and termite attack. Excellent weathering characteristics. Older is more durable than younger trees. Low density and soft, easy to work, needs to be machined with sharp cutters and extra sanding up to finer grits to get smooth surface, cedar like scent, aromatic

Sapele  (Sapele Mahogany)
Entandrophragma cylindricum
Specific gravity is .50
Diffuse porous, hardwood found in Africa, golden to dark red-brown color, darkens with age, variety of grain patterns since it is interlocked with fine uniform texture, moderate to very durable to decay and moderate insect/borer resistance, difficult to work with due to interlocking grains, reacts with direct contact with iron (color change), glues and finishes well, occasionally substituted for genuine mahogany

Honduran Mahogany (Genuine Mahonay)
Swietenia macrophylla
Specific gravity is .52
Diffuse porous, found in southern Mexico to central South America in plantations, pinkish brown to dark red-brown color, straight grain, moderately durable to rot, resistance to termites but not other insects, easy to work with tools and machines well, sands easy, finishes well, no odor

Swietenia mahogani
Specific gravity: .53
Diffuse porous, found in southern Florida and Caribbean, Pinkish brown to dark red-brown color, darkens with age, straight,interlocked, irregular, or wavy grain, medium uniform texture, moderately durable to rot, resistance to termites but not other insects

Quercus virginiana
Specific gravity is .80
Diffuse porous, found in the southern USA, light to medium brown color with straight grain that has a coarse uneven texture, easy to glue and takes stain and finishes well. Difficult to work cut or work with during to its incredible density, need very sharp saws and tools to work with the wood.

Quercus alba
Specific gravity is .60
Ring-porous, found across USA, straight with a coarse, uneven texture, light to medium brown and emits slight olive tints and exhibits a fairly straight grain, very durable and rot resistant

Microberlinia brazzavillensis
Specific gravity is .67
Diffuse porous, found in west Africa, light brown or cream color with dark blackish brown streaks vaguely resembling a zebra’s stripes, airly coarse texture and open pores, wavy or interlocked grain, resistant to insects

Honey Mesquite
Specific gravity is .70
Diffuse porous, found in southwest USA, chocolate- brown wood, similar to black walnut. Sap wood is a yellow/tan, straight grain and coarse pores texture, very durable regarding decay resistance, knots are common

Teak (Verbenaceae / Lamiaceae family)
Specific Gravity is .55
Ring-porous or semi-ring-porous, found in southeast Asia, straight or interlocked grain pattern and its heartwood is usually a medium brown and darkens with time. highly resistance to decay and wood consuming organisms. Its heartwood is extremely durable, straight, though it can occasionally be wavy or interlocked, coarse, uneven texture

Black Cherry (Rosaceae family)
Specific gravity is .47
Semi-ring-porous to diffuse-porous, found across USA, very durable and resistant to decay, straight with rarely curly grain patterns, fine even texture, color light pinkish brown after cut, darkening to a deeper golden brown with time and upon exposure to light

Balsa (cork) (Malvaceae family)
Ochroma pyramidale
Specific gravity is .12
Diffuse-porous, perishable, and susceptible to insects, sapwood is white to off-white or tan color, should not be used to hold nail, fact sheet
FYI: most interesting tree that I researched this year

Araucariaceae Agathis australis
Specific gravity is .44
From northern New Zealand, pale yellowish white to golden brown heartwood, vulnerable to insect attack, low durable to rot, straight with a fine, even texture with only one authorized US dealer in Wisconsin 

From Te Ara Encyclopedia of New Zealand 


Kauri trees bear both male and females cones. Its bark is gray with a circular marks caused by the bark flaking off. The younger kauri (up to 120 years) have long self-pruning bole (rickers) and elasticity which made it ideal for the ships' spars. The gum known as New Zealand amber oozes from the bark of the mature trees. The gum was valued more highly than the wood; it could be used for fire starter, medicinal purposes, soot from burnt gum for tatooing pigment, and straight grain, buoyant timber was ideal for canoes.

The seedlings are shade tolerant that change to shade intolerant once established. The trees reach the forest canopy in about 50 years or more.

While the final size depends on the the site index and the conditions, the average height is 90 to 120 feet and the ground stem diameter can reach several meters in diameter. By 600-700 years old, kauri reaches an average diameter of over 39 inches. They can survive for 1,000 years or more with an average diameter of 79 inches, but trees older than 1,700 years are more rare (diameter of more than 118 inches).

The age of the largest survivors like Tane Mahuta (the god of the forest) with a diameter of more than 158 inches is not accurately known, possibly 2,000 years old. Even bigger trees were known in the past, some with diameters of more than seven meters (276 inches).

This litter eventually develops into a highly acidic humus that is slow to release nutrients. It is another strategy by which kauri edge out competing broadleaf species. Which builds up to four times the nitrogen stored in the litter of other forest types. Kauri forest produces nearly twice the amount of wood, bark, and cones for a given amount of nitrogen than that achieved in other forest types because of its mycorrhiza."

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