Bobbsey Twins on the Deep Blue Sea
Author: first_name: Laura Lee
last_name: Hope
Language: English
Year: 1918

This is the 11th in the original series of books about the Bobbseys -- two sets of twins in one family, solving mysteries and having adventures. Bert and Nan are 12, Flossie and Freddie are six. There is a father who works, a mother who stays home, a cook, a handyman, and an assortment of animals. 
 - Summary by Nan Dodge

Laura Lee Hope is a pseudonym used by the Stratemeyer Syndicate for the Bobbsey Twins and several other series of children's novels.