Why Spanish ships were built more heavily

What construction differences made Spanish ships tougher than French ships?

Spanish yards used better-seasoned wood, somewhat heavier framing, and thicker planking for long ocean voyages and treasure-fleet duties.

Spanish yards seasoned their timber for longer and drew on established arsenals comparable to those available to Britain. Their ships also tended to have somewhat thicker planking and heavier framing than French vessels. Those choices suited long ocean voyages and the demands of the treasure fleets.