10/01/2025
TIGHT LINES
A explanation of the importance of maintaining proper tension in hoists.
written by Tony Caldarelli
edited by William "Drew" Hough
If you’re fishing with friends, you may have heard your friends wish you “tight lines”. To the saltier among us we understand this to mean something along the lines of “good luck” or “break a leg”. When you hook a fish, the fish will pull against your fishing line, putting tension on it. The tighter your line, the harder it would be for the fish to break away. So, the “tight line”, a line with tension on it, is a good thing when casting.
In the world of cranes, having tight lines is a good thing too. Not only that, but having tight lines is mandatory. If you break off a fish when fishing, you should grab your line and reel it in while tensioning it, because if you don’t, the line will tangle as it is being wound on the reel. With a crane hoist, the same thing happens. If tension isn’t constantly maintained on the wire rope, it will not wind properly onto the hoist drum or lay correctly in the sheaves (we call this reeving).
Wire rope that is improperly reeved on a crane is a major hazard as it can become damaged, jam the hoist system, cease operations, or even cause the wire rope to snap, which can cause the load to drop, potentially posing a threat to workers. So, to always ensure there is tension on our wire rope, overhaul balls or load blocks can be used, they not only connect to the load hook to the hoist line, but they also help by providing extra weight, this extra weight is called overhaul weight. All of this helps to properly tension the wire rope.
What is the appropriate additional weight? That will depend on several factors, such as the boom length, the size of the wire rope, the parts of the line reeved, and more. The block on a small service truck crane might weigh 20 pounds. At the other end of the spectrum, one of our employees inspected a crane whose load block weighed 33 tons!
The simple solution to find this out is to follow the manufacturer’s guidance in the load chart or some other manufacturer’s material. Service trucks and lower-capacity cranes may only have one device. Just be sure that if it needs to be replaced, the replacement is what is required by the crane manufacturer. Larger capacity machines may have one or more headache balls and several load blocks of various weights and numbers of sheaves. Some load blocks have side plates or cheek pieces that can be bolted on to increase the overall weight. Always make sure to use the correct attachment in the correct configuration for the manner in which the machine is rigged according to the manufacturer’s guidance.
Maintaining proper tension on hoist systems keeps the reeving of the system correct and minimizes excessive wear, damage, and the potential for dangerous incidents. So, keep your rope tensioned and stay safe out there. And “Tight Lines!"
