referenced and talked about in Philbrick's "In the Heart of the Sea". He has a Note about it in his "NOTES" for each chapter at the end of the book. I don't have my book with me, otherwise I could tell you where it is. These guys were out for 2-3 years at a time. How did the wives know when to get up there an start looking ?!? They probably had better things to be doing. I wonder how many McMansions on Nantucket have these elaborate structures on the rooftop … and no where near the darn chimney ! Cheers, John