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GOOD SLINGING PRACTICE BASIC RULES ... 5 5.1. KNOW THE EFFECT OF REEVING ON SLINGS. "Reeving" is the practice of wrapping a sling around an object, and either doubling it back on the hook, or passing one eye of the sling through the other and then to the hook. This practice is also known as "choking", or "nipping". This practice is perfectly safe when done properly, BUT you MUST realise that the act of reeving creates an "included angle" within the sling which reduces the permissible load on that sling. And NEVER bang the hook down on to the load. You are NOT making the sling more secure - in fact, you are creating larger loads in the sling by increasing the included angle. It also increases the crushing force on the load. Any sling reeved around a load needs to have a SWL which is TWICE that of a vertical sling. To work out the sling loads for a reeved sling, use the following formula. This will work for any reeved sling with an included angle LESS that 120°, which must be the absolute maximum angle. An example has been shown. R Load = W. Note protection on sharp corners. L T = Tension in each slinging leg. L = Length of each leg. R = Rise. W = Load to be lifted. CRANEAGE - SLINGING: BASICS PAGE 10 T = 1/2 W x L R
GOOD SLINGING PRACTICE BASIC RULES ... 5 5.2. KNOW THE EFFECT OF REEVING ON SLINGS. When a load is lifted by a pair of equal-length slings, the load in each leg of a sling increases as the angle between the legs increases. We then have the seemingly ridiculous situation where the load on a sling can be many times the actual weight of the load - a frequent cause of sling failure. 1,000 kg 2,000 kg 1,000 kg 1 tonne Single leg sling 1,000 kg 1 tonne 2,000 kg 60° 90° 120° 1,155 kg 1,414 kg 2,000 kg 11,470 kg LOAD ON ANGLED SLINGS Reeving a sling around a load with one eye (or bight) through the other, actually halves the safe working load of that sling. Keep in mind also, that the angle of the sling has already reduced the capacity of the sling. If it were possible to reeve the sling and keep the nip well above the load, this load would not be so great, but safety requires the nip to be well down on the load. 1 tonne Reeved, nip, or choker sling Angle A Basket or cradle sling A sling which is to be reeved around a load needs to have a safe working load of AT LEAST TWICE that of a sling which would otherwise be used. 2,000 kg 2,000 kg 2,000 kg 2,000 kg 2,000 kg 2,000 kg 0.5 tonne 1 tonne 1 tonne Bridled sling 2,000 kg 170° 0.5 tonne PAGE 11
Page 1 and 2: NOTE: This is Part 2 of a 4-part mo
Page 3 and 4: CRANEAGE - SLINGING BASICS SECTION
Page 5 and 6: GOOD SLINGING PRACTICE BASIC RULES
Page 11: CRANEAGE - SLINGING BASICS SECTION

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