The caption reads:
"The International 5O5 Class
This class is of reasonably recent date and has leaped into prominience as a most practical and exciting dinghy to race. Large numbers have been built in England and France. They are well decked in and comfortable. Trapezes can be used by the crew to enable them to sit well out to winward. They are virtually unsinkable and if they capsize can be quickly righted, and sailed on, the water escaping through scuppers in the transom."
Thanks to Witold Gesing who sent us this photo!