Is a defect in design a latent defect in the machinery covered by an all-risk policy?

The fifth exception is latent defect. The defendants argue that defects in design become either latent defects or inherent defects, or both when construction is complete. In Jackson v. Mumford the plaintiff shipowners argued that a weakness in design which had caused a connecting rod in a high pressure engine to break was a latent defect in the machinery, a risk covered by the defendant’s all-risk policy. The trial judge, at p. 18, was unable to accept that argument, finding that it was: … not a natural interpretation of the words, or a meaning which any man of business reading the expression in a commercial document would attach to it. The phrase “defect in machinery” in a business document meant a defect of material, in respect either of its original composition or in respect of its original or its after acquired condition.