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Sail Question


gieb8688
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There WERE preservatives used on natural fiber sails. If you have ever seen red sails on a vessel those are Tanbark sails. Tanic acid from tree bark has been used traditionally as a means of preventing or delaying rot in cotton canvas. This was more common in Europe but some sailors today still use the sails on traditional rigs. Also you can get dacron in a red color that mimics Tanbark. If you goggle "tanbark sails" you get this:  http://www.google.com/search?client=safari&rls=en&q=tanbark%20sails&oe=UTF-8&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi

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The tanning of sails was only done on small(er) boats, where there often was, due to their operating conditions, no opportunity to dry the sails before stowing. The tanning, which involves dyeing the sail in a bark solution and applying a mixture of tallow/oil with yellow or red ochre, makes the sails somewhat water repellent and resistant against mould (the main objective), but at the expense of slightly damaging the fibres. Tanned sails are not as strong as undyed sails for the same material.

 

wefalck

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Canvas comes from old French “canevas” or “canevaz”, literally, ‘made of hemp’. Over the years, it morphed. The Dutch, not being able to grow cannabis, used flax; they called it “zeildoek”, literally, ‘sail cloth’. The weight of the cloth (pounds per square whatever) determined its usage. The lighter grades were called linen, the heavier grades were called canvas (presumably because some hemp fiber was incorporated into the weave).  After a while, sailcloth was just called “duck”; soft-duck, hard-duck, canvas-duck, etc..

 

The Russians developed a technique for double carding flax to make it more pliable. It was very useful on linen-weight and intermediate-weight cloths. Sailcloth prepared in this way eventually became known as, simply “duck”. The heavy-weather stuff was still, simply “canvas”.

 

All made on hand looms, till about 1800, so the lighter, softer, fibers made for a more tightly woven, resilient, and stronger cloth (for its weight) than the larger fiber flax/hemp equivalents. For all its advantages, the cost (and time) needed to trim, card, and twist flax into fibers of a size useable for courses or topsails, made it uneconomical for all but the wealthiest. The Russian Navy used it, but then, the Czar said so, so …

 

The colonies were cut off from internal manufacture of this sort in the normal course of events, and during the unpleasantness, were supposedly cut off from  Euro imports altogether, so we had to do something. There was decades of experience with cotton as an alternative to flax, but it was all simple short staple: hardy, coarse, but flexible, it wasn’t much better than flax, and cotton had the disadvantage of being more hygroscopic than flax. Okey dokey, except for the weight aloft rule.

 

Then somebody (who deserves a statue) thought about the long-staple Sea Island variety. Not as hardy, but just as flexible, if not more so, but could also be carded fine, and woven tight. Because the fibers could be linked and twisted, it was a perfect solution for light and intermediate sailcloth weights. The biggies, of course, still used hemp in the weave. Until about the 1800s or so, when the power loom came on-line and could weave ‘tighter and lighter’ than before.

 

So, even today, sailboats raise “canvas”, even though it’s Dacron. Rarely, will you hear the term duck. Hemp is what ya smoke, and flax is what happens to your winkie with too much hemp.

 

I really hope I haven’t given you more information than you really wanted.

 

Ciao. John

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Weflack,

 

Our boat has tanbark sails:

 

post-335-0-61940800-1366673476.jpg

 

One interesting thing about tanbark. On cotton sails, it was used to extend the life of sails. On Dacron sails, Tanbark sails are more UV sensitive than white dacron sails, and tend to fade and degrade faster :o

 

Thanks,

 

Harvey

 

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I suppose Dacron sails are not 'tanned', but the fibre is coloured. It is not so surprising that coloured sails age faster than white ones, as the so-called albedo is lower, i.e. the reflectance for light. This means the sail absorbs more energy that can destroy pigments. Obviously the pigment used in colouring the dacron fibres is not light-fast. The red or yellow ochre used in the 'real' tanning procedure is a mineral pigment, iron (hydr)oxide, which is light-fast, but may change its hue to changes in the amount of water incorporated into its chemical composition.

 

wefalck

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I think you're correct. Unfortunately, the understanding of fabric (either natural or synthetic), its design, construction and coloration is not my forte. I have "The Sailmaker's Apprentice" by Marino, but I haven't dug into it much. Maybe after I learn to sail and learn to build ship models :huh:

 

Thanks,

 

Harvey

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