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Old 02-06-2017, 01:38 PM   #15
TJM
Senior Member
 
City: Essex, Ct.
Country: USA
Vessel Name: Harmony
Vessel Model: 1982 41' President
Join Date: May 2013
Posts: 183
Being an Engineer I always look at the applied load vs how the designer intended the product to be used. The reason a spreader bar is used is to keep the load on the dinghy eye pads as designed, directly upward.
The chain usage in the post above applies a horizontal load (inward) on the dinghy. It may be fine but fiberglass does not give you any warning before failure, it cracks.

The spreader bar needs to have a thick vertical cross section, like a 2 x 4.
Typically SS or Aluminum tubing is used with a welded stiffener on top. 1/2" x 4" is usually strong enough. Tube diameter is a better characteristic than a thicker wall.
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Tom and Cheryl
"Harmony"
1982 41' President
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