TECHNICAL INFORMATION
1) GETTING THE MOST USE FROM A POLY TARP
Polyethylene tarpaulins are an ideal lightweight, economical covering product for which there are many uses. Much easier to handle and less expensive than canvas, poly tarps are constructed by cross weaving strands of polyethylene yarn then laminating the material on both sides. When comparing tarp quality consider that more cross weaves per square inch results in a tighter weave which adds strength and durability to the finished product. The edge hem is reinforced with a sewn in polypropylene rope on all sides and aluminum grommets are added for tie down convenience.
Poly tarps are commonly used for pool and boat coverings as well as storage and construction coverings. Designed to be lightweight yet strong, poly tarps can be susceptible to pre-mature failure from wind damage if not properly secured. Whether using a tarp to cover a roof or a log pile, remember to use as many tie down points as possible and minimize any slack
2) TYPES OF ROPE CONSTRUCTION
Rope is constructed in two basic ways, laid and braided, although there are variations on the theme. The first is "3 strand" line. The direction of twist is called the lay of the rope. Three strand twisted line can be "laid" right or left, and should always be coiled with the lay of the line. This rope is described as S-laid (left-laid) or Z-laid (right-laid) according to whether the twist follows the line of the center part of the letter S or Z. Most three strand rope is Z-laid (right-laid) If you hold a length of 3 strand right-hand laid twisted line at arm's length and eyeball it, you will see the wrap of the line twisting to the right.
The construction of stranded line, whether natural or synthetic, is much the same. Individual fibers are twisted into yarns, the yarns are twisted into strands and the stands are twisted into line. Right-laid is twisted clockwise and left-laid is twisted counterclockwise. The fibers are twisted in the same direction as the strands, however the yarns are twisted in the opposite direction. This right, left, right for right-laid line helps give strength, keep the line from kinking and hold its shape.
The other construction type is braided line. This type of line does not stretch to the degree that twisted line does, and is more difficult to splice. However, it goes through a pulley or block very well because of its rounded shape, and is stronger than its equivalent-sized twisted line. Braided line also tends to snag when used as docking line if the pilings are rough.
A variety of braided lines are available:
- Braid on Braid has a braided core inside a braided sheath - will stretch less, and has less flexibility, than a hollow braid.
- Multibraid is braided with 2 pairs of Z-laid and two pairs of S-laid strands – it is flexible and does not kink.
- Parallel Core has a braided sheath over a core of straight or lightly twisted yarns – it is very strong.
- Hollow Braid has no core – is very flexible but can flatten during use. It is only found in small sized rope.
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