Camping and woodcraft - Scoutmastercg.com

32 CAMPING AND WOODCRAFTmade of plain cotton duck. A single roof of suchmaterial will shed rain, if the stuff is closely woven,but only so long as it is stretched at a proper angle,rather taut, and nothing touches it from the inside.If so much as a finger-tip should be rubbed againstthe under side of the roof, a leak would springthere, due to capillary action. It is of little use todraw the finger from the drip spot down to the tentwall, for, although this runs the water off for atime, fresh dripping will start on each side of theline.Nor is it possible to avoid slackness in a roof ofplain canvas during a wet spell of weather. Cloththat is not water-proofed will shrink a great dealas soon as it gets wet ; hence the guy ropes must belet out, and the roof allowed to sag, before the rainzomes; otherwise the shrinkage of the canvas willloosen your tent stakes, or even pull them all uptogether, when down goes your house about yourears!For these reasons, a tent should either be waterproofed,or should have a supplementary roof called,a fly. These matters will be considered later.Cotton duck comes in three geneial grades, knownas single filling, double filling, and army duck.Single filling duck is made of coarse yarn, looselywoven, and of an inferior grade of cotton. It issuitable only for cheap tents that are not intendedfor continuous use, and generally is a bad " bargain" even then. It is weaker than the same weightof the other grades and is poor stuff to shed water.Double filling duck is of closer texture, betterfiber, and is equal to all but the hardest service.For average summer camping It Is good enough.Army duck Is the best grade made, of selectedcotton free from sizing, both warp and fillingdoubled and twisted, closely woven, and free fromimperfections — if It comes up to army standard.It will outwear any other tent material of the sameweight, except flax (which I have not seen used