Good to hear that you are considering an ISO, below are a few things to watch out for when buying a second hand ISO. The only problem at the moment is that the class is popular and the second hand boats tend to sell quite quickly. In the meantime here are a few pointers;

• Mast;
  Look for compressed sidewall at spreader bracket or at frame level.
  Also check for cracks at the hounds.

• Hull;
  Most are lasting well. On early numbers (pre 750) check for excessive floor cracks in the crew area. These are mainly superficial, but will absorbe moisture never the less.

• Foils;
  Check the boat has foam (not GRP) daggerboard if the number is over 600. GRP boards are banned on boats over 600 (except for 7 boats that have dispensation). New board is about