The Bobbsey Twins at the Seashore is the original version of this book from 1907. The Bobbsey Twins: The Secret at the Seashore is a complete rewrite of the book dating to 1961. Source: http://home.netcom.com/~drmike99/Bobb...
References to this work on external resources.
Wikipedia in English
The Bobbsey twins visit Ocean Cliff, the seaside home of their cousin Dorothy. While there they enter the water carnival, play on the beach, and witness a shipwreck.