Passage Maker - - Contents - Steve Zim­mer­man

Driv­e­trainWear & Tear

Ex­te­rior wood on a fiber­glass boat adds a touch of warmth, tra­di­tion, and style that can­not be du­pli­cated any other way. From a purely func­tional point of view, ex­te­rior wood makes no sense at all, but for most of us boats are more than purely func­tional ob­jects. I’ve al­ways thought that for a boat to be the right one for you, it must pass a sim­ple test: when you leave in the dinghy, do you find your­self look­ing back and ad­mir­ing her? If you feel com­pelled to make a lap around the boat be­fore head­ing ashore, all the bet­ter. Af­ter all, in ad­di­tion to safely trans­port­ing you and your crew from points A to B, a boat should tug at your heart­strings along the way.

Wood needs at­ten­tion, and boat own­ers must choose from a daunt­ing ar­ray of care op­tions. Be­fore we look into the pros and cons of the coat­ing choices, we need to look at the con­di­tions that de­ter­mine the longevity of the fin­ish. Coat­ings face four threats: UV ex­po­sure, abra­sion, mois­ture, and move­ment. As soon as you ap­ply the last coat of fin­ish, the el­e­ments be­gin their at­tack. Ul­tra­vi­o­let rays break down the chem­i­cal struc­ture of the coat­ing. Paints in­clude pig­ments that block out UV rays, but clear fin­ishes strug­gle in this area. Abra­sion comes in the form of chafe from lines, salt crys­tals left to dry, and dirty shoes. Mois­ture might pose the strong­est threat. If mois­ture col­lects in the wood be­neath the coat­ing, the bond will break down caus­ing dis­col­oration, at best, and loss of ad­he­sion of the coat­ing from the sur­face, at worst. Fi­nally, move­ment of the wood sur­face, es­pe­cially at joints, can wreak havoc with the fin­ish.

There is no sil­ver bul­let, no one-siz­e­fits-all, and no clear an­swer on what prod­uct you should use. Con­sider all of the vari­ables in play. A boat based in New Eng­land likely will have three months of ex­po­sure in a tem­per­ate cli­mate, fol­lowed by nine months un­der Tung oil var­nish re­mains a fa­vorite due to its rich fin­ish and pleas­ant scent. Here’s the pay­off for all that sanding and clean­ing— lay­ing down a beau­ti­ful fin­ish coat.

cover. An­other boat might spend win­ter in Florida, spring in the Ba­hamas, and sum­mer on the Ch­e­sa­peake. One owner might ap­ply a pro­tec­tive coat­ing or two ev­ery sea­son while an­other might go ev­ery two or even three years. One boat might have tightly fit­ted, glued caprail joints, while an­other might have caulk­ing in the joints, al­low­ing for greater move­ment and ac­cu­mu­la­tion of mois­ture.


Many cruis­ers leave their ex­te­rior teak un­fin­ished. Do­ing so will not cause any im­me­di­ate harm, but it still re­quires care. When wash­ing bare teak, be gen­tle, be­cause scrub brushes and high-pres­sure wa­ter will re­move the softer grain, leav-

ing hard ridges that look un­sightly and feel rough. For this rea­son, never brush bare teak along the di­rec­tion of the grain.

Teak nat­u­rally grays as sur­face oils ox­i­dize and it tends to sta­bi­lize in these con­di­tions. If you have wa­ter stand­ing in low places, moss and mold can de­velop and an oc­ca­sional clean­ing will be nec­es­sary. When sell­ing a boat, wood in this con­di­tion will be an is­sue. First, you can­not es­cape the lack of curb ap­peal and, fair or not, bare gray ex­te­rior wood gives the im­pres­sion of a poorly main­tained boat. Sec­ond, most buy­ers will want a coat­ing on the wood, and the cost to bring the bare teak to beau­ti­ful fin­ish will be sub­stan­tial and will im­pact the sales price.


Each coat­ing can be eval­u­ated against four cri­te­ria: ease of ap­pli­ca­tion, ap­pear­ance, dura­bil­ity, and main­te­nance re­quire­ments. Let’s start with tra­di­tional oil-based var­nishes. Var­nish can be de­scribed as a clear pro­tec­tive coat­ing ap­plied to wood. It can be traced back thou­sands of years to resinous pine forests in the Mid­dle East and North Africa. One city in par­tic­u­lar, Berenice, was fa­mous for its var­nish–change the “B” to a “V” and it sounds a bit like “var­nish.” That city re­mains to­day, though its name has changed. Maybe you’ve heard of it: Beng­hazi. Var­nish con­sists of three pri­mary com­po­nents: resin, oil, and a sol­vent. Mod­ern var­nishes con­tain other ad­di­tives to pro­tect against UV, pro­mote flow, and pro­vide elas­tic­ity. A va­ri­ety of oils can be used, but tung oil (tung oil trees flour­ish in south­ern China) pro­vides the best mois­ture re­sis­tance and gloss re­ten­tion. Tung costs more than lin­seed oil, for ex­am­ple, but pro­duces bet­ter re­sults. The higher the oil con­tent, the bet­ter the var­nish.

For those in­clined to main­tain their own wood, noth­ing com­pares to the feel and smell of tra­di­tional var­nish. It has a nat­u­ral golden hue which adds depth and rich­ness to the look of any wood and an ap­peal­ing scent when ap­plied.

When start­ing from bare wood, oil­based var­nish has three draw­backs: only one coat can be ap­plied each day, sanding is re­quired be­tween each, and at least eight to ten coats will be needed to pro­vide proper pro­tec­tion and to fill the grain pat­tern. An­nual main­te­nance re­quire­ments will vary depend­ing on cli­mate and ex­po­sure, but most boats will need at least two coats an­nu­ally.

Ship’s stores of­fer a be­wil­der­ing ar­ray of oil-based var­nishes. In­ter­lux of­fers Schooner® and Schooner Gold®, West Marine has Pre­mium and Ad­mi­ral’s, Pet­tit in­cludes Cap­tains and Flag­ship. Per­haps the most mis­pro­nounced brand comes from Hol­land, called Epi­fanes (epee-fanus), which of­fers a whop­ping 64% solids in a tung oil­based var­nish (com­pared to less than 50% solids in other brands, and mix­tures of tung and lin­seed oil in many other brands).


Sikkens is a brand name of Ak­zoNo­bel, a Nether­lands-based com­pany which of­fers a sealer known as Ce­tol®. Ce­tol, an alkyd-based sealer, oc­cu­pies a unique niche in the coat­ings mar­ket by com­bin­ing a pig­mented satin ap­pear­ance along with ease of ap­pli­ca­tion. Ce­tol can be ap­plied at the rate of one coat per day, with no sanding re­quired be­tween coats.

From bare wood, only three or four coats are re­quired. An­nual bare spots must be treated, and then one or two main­te­nance coats ap­plied. Ce­tol fin­ishes breathe, al­low­ing mois­ture to pass through, mak­ing it less likely that mois­ture com­ing from a joint or bed­ding will un­der­mine the fin­ish.

Fif­teen years ago or more, many of us came to know Ce­tol as heav­ily pig­mented stain, often leav­ing an or­ange hue on teak. About eight years ago Sikkens mod­i­fied the for­mu­la­tion and the newer prod­ucts leave a more nat­u­ral fin­ish. If you value ease of ap­pli­ca­tion over aes­thet­ics, Ce­tol pro­vides a good op­tion.


Urethanes fall into two cat­e­gories: one-part (alkyd type) and two-part (iso­cyanate-based). The well-known Awl­grip® prod­uct line in­cludes Awl­wood™, a third type that is chem­i­cally sim­i­lar to a two-part that is supplied as a one-part. When re­fin­ish­ing from bare wood, their clear, red, or yel­low low-vis­cos­ity primer soaks into the sur­face and bonds with the wood. The Awl­wood clear fin­ish then bonds chem­i­cally to the primer, re­sult­ing in a high-ad­he­sion seal­ing sys­tem. This prod­uct is very flex­i­ble which, com­bined with the primer ad­he­sion, re­sults in a tena­cious fin­ish. The man­u­fac­turer claims longevity of three to four times greater than con­ven­tional var­nish. From bare wood you will need roughly eight coats af­ter the primer has been ap­plied, with a main­te­nance coat ap­plied ev­ery year or two. Mul­ti­ple coats can be ap­plied in a sin­gle day, but sanding is re­quired for next day ap­pli­ca­tions. The over­all thick­ness is more im­por­tant than the num­ber of coats as this is what pro­vides longevity. It also has a satin fin­ish which can be used for both in­te­ri­ors and ex­te­ri­ors. Al­though Awl­wood can be ap­plied over some ex­ist­ing coat­ings, the man­u­fac­turer rec­om­mends re­mov­ing all traces of pre­vi­ous fin­ishes. It pro­vides a high gloss, durable coat­ing, but re­quires pro­fes­sional ap­pli­ca­tion.

The stain­less gate hard­ware cov­ers the end grain of the wood, a crit­i­cal area where the fibers soak in mois­ture. The hard­ware should be re­moved, the end grain sealed with epoxy, and new bed­ding com­pound ap­plied.

Can­vas will pro­tect the wood and its coat­ings from UV rays and from mois­ture. The can­vas comes with its own main­te­nance cost, plus the ef­fort to re­move and in­stall it each time you get un­der­way. For a boat left for long pe­ri­ods of time, the can­vas will gr

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