> At 08:33 PM 1/4/05 -0600, you wrote: > >Even a single chain hook does not distort the chain. Chain hooks are used > >on truck load binders routinely and I have not heard of a problem > > A single chain hook does not distort a single chain link. But it will > pull at an angle to the chain proper. > Is there a semantic issue here. > Mike ------------------- It is incorrect and dangerous to believe chain hooks do not reduce the load that a chain will fail at. > >Even a single chain hook does not distort the chain. Chain hooks are used > >on truck load binders routinely and I have not heard of a problem This only means the chains of so oversized the strenght reduction is not a problem. I do not know much about truck loads, but it appears they are holding static items/loads and the chains do not have thousands of pounds of force on them. I see the chains held in place with devices that are hand installed and tightened. To expand on Mikes comment. The chain hook is at an angle to the direction of pull. (It has to be because the pull in not in line with the flexible chain it is pulling) This means that if a 1000 lb force is applied to the chain hook the resulting force has two components That which is in line and that which is 90 degrees to the line. To compute the inline force the calculations are (remember to place your calculator in deg mode when using your calculator to do your own calculations) in line force is cos(angle) * your pull. side force is sin(angle) * your pull. Angle is 180 degree's minus the angle between the chain hook and the line attached to the chain hook, not the anchor chain. If the angle is 150 degree's (so the chain hook is pulling 30 degrees back from being perpendicular to the chain) the inline force on the anchor is cos(30) * 1000 = 866 lbs the side force on the chain is sin(30) * 1000 = 500 lbs. To double check your work the square of each computed number should equal the square of the original force. 866^2 + 500^2 = 999,956 the square of 1,000 is 1,000,000. This shows that a chain hook inparts significant side loads. A chain plate with a pull on both sides is much closer to perpendicular and has far less side load. Tip of the day: the same principles are used with a sextant to measure distance of of a land from the height of a known object (light house light or tower). height in ft / tan(angle from sextant) = distance off in feet. Or my favorite use, will I fit under a bridge... I used a laser range finder, a sextant and a known height of the sextant off the water when standing in the Portuguese bridge.

We went through this subject on the T&T list a little while ago. First, there are chain hooks and then there are chain hooks. A Campbell hook placed on a chain rode does what Scott says it does - imparts a side load. If you go to the Washington Chain website, you will find at least two types of chain "hooks." One is available in SS and sits astride the chain placing an equal load in line with the chain. I won't try to further describe it. The other is sold cast steel and is their Marquip brand. I just found two on my boat. These also place an equal load in line with the chain. Prior to their discovery, I was using the Windline unit, which as Bob Austin said, resembles the plate of their chain stopper and has holes for snubber lines on both sides. Although the Marquip does eventually rust, it is of very heavy construction and worth a visit to the Washington Chain website. Mine are for 3/8" chain, but the website shows huge ones. You might have to call to get a small one. I'll bet they are around $20 each. Ron Rogers