How many skip welds and adhesive are needed to attach roof bows?

The correct answer indicates that 7 skip welds along with adhesive are necessary to securely attach roof bows in the construction of dry vans. This method is essential for ensuring strength and stability in the roof structure, as roof bows play a critical role in maintaining the integrity of the trailer's upper framework.

In manufacturing, skip welding is a technique that involves placing welds at intervals rather than continuously. This approach aids in reducing warpage and allows for thermal expansion, ensuring that the roof bows remain securely attached without compromising the overall shape of the trailer. The presence of adhesive further enhances the bond between the materials, improving their resistance to shear and tensile forces that can occur during operation.

The other options suggest different numbers of skip welds, which would either under- or overestimate the amount needed for reliable attachment. Using fewer than 7 skip welds may lead to insufficient structural support, whereas using more than necessary could lead to unnecessary complexity and material usage. The combination of 7 skip welds with adhesive represents an optimal balance for effective attachment of the roof bows.