A shackle has to provide the security of connection between two parts. Its choice cannot be haphazard. Shackles available are made out of stainless steel and are designed hold and withstand the elements. Install one of these shackles that have a larger opening for the halyards or other connections you need to makeon your boat.
Open shackles have a similar shape to "D" shackles but are proportionally wider for their length. They have a smaller maximum working load due to the long pin length. Because of this, it is especially important to consider the loads involved in your application when using a large open shackle.
About Harken Large Open Shackles
The maximum working load on the Harken 5mm large open stainless steel shackle is 770 pounds which is 350 kilograms. The Breaking load is 2200 pounds or 1000 kilograms. The breaking strength on the Harken Large Open Stainless Steel Shackle is derived from tests that support 80% of the length of the screw pin that is unsupported, which is similar to the area of a post in a block. Safe working loads are no more than half the minimum breaking strength.
About Wichard Self-Locking Large Opening Shackles
The sizing of open shackes is based primarily on the pin size but it is important to also check the other dimensions to ensure a proper fit for yout application. All dimensions, including working loads, breaking loads and weights can be found on the Wichard Large Open Shackle page linked to above.
We at Mauri Pro Sailing are fully committed to be your Open Shackle specialist not only providing the sailing community with a comprehensive and easy to use web site but with all the appropriate technical information that you might need to select your sailboat hardware and equipment. If you need any assistance selecting the appropriate Large Open Shackle for your boat or application please contact us. Our crew is ready to help!