Several years ago, the History Channel (I think it was) aired a documentary on this doomed fleet and intimated the enslaved shipbuilders may have deliberately sabotaged the ships by employing substandard materials and shipbuilding techniques, knowing full-well they would come apart in heavy seas. Revenge is a dish best served cold.
Incidentally, those fleets were enormous. Very impressive. The second one had over a thousand ships in it, iirc. Untold thousands drowned. Really knocked the wind out of the Mongols.
Must have been sailing ships. :-)