LemmyCaution
Member
- Joined
- Jun 4, 2008
- Messages
- 897
For anyone interested-
A shackle rigging connection does not gain strength by being wrench tightened. Quite the opposite- wrench tightening a shackle puts a load on the bow that reduces the strength of the connection. One mouses a shackle because ideally the clevis pin is installed finger tight. There needs to be some means of preventing the pin from backing out under vibratory or shifting load.
Frequently, when a shackle has been loaded at or near its capacity, the pin will become stuck. Or, in salt air or exposed to spray, galvanic corrosion will gall the threads of the clevis pin. In these cases, the shackle cracker, or breaker, is used to loosen the stuck pin. The shackle cracker should not be used to tighten a pin, unless absolutely necessary (because one has nothing to use for mousing), and the load is assured of being static and constant (because no matter how tight one gets the pin, it will back out under a vibratory or rotational load).
A shackle rigging connection does not gain strength by being wrench tightened. Quite the opposite- wrench tightening a shackle puts a load on the bow that reduces the strength of the connection. One mouses a shackle because ideally the clevis pin is installed finger tight. There needs to be some means of preventing the pin from backing out under vibratory or shifting load.
Frequently, when a shackle has been loaded at or near its capacity, the pin will become stuck. Or, in salt air or exposed to spray, galvanic corrosion will gall the threads of the clevis pin. In these cases, the shackle cracker, or breaker, is used to loosen the stuck pin. The shackle cracker should not be used to tighten a pin, unless absolutely necessary (because one has nothing to use for mousing), and the load is assured of being static and constant (because no matter how tight one gets the pin, it will back out under a vibratory or rotational load).