Clue: Like 78 yachts at sea rounding Costa Rica (8)
Answer: SCRATCHY
Explanation: Definition: Like 78

***(yachts)** [anag:*at sea*] *rounding* **CR** (Costa Rica)
 

 
*A 78 was an old record that played at 78rpm. They were popular until the 1950s. Like all records, they would have become scratchy, but to my mind this is a weak definition.