A Detailed Study of H4

A new DVD is available, which charts the completion of a working replica of John Harrison’s H4 navigational timepiece. A review is now available along with details of how to purchase the DVD.

This DVD will help to raise money for Prostrate Cancer UK, in memory of brilliant watchmaker Derek Pratt, the inspiration behind the project. 


Derek inspired the replica project and was able to complete around half of the project before the disease claimed his life. A team from Charles Frodsham & Co completed the project.

Barbara Darby, who has produce the DVD, explains:  ‘I'm sure that many Guild members and horologically minded associates are aware that, over the last 19 years, a working replica of John Harrison’s H4 navigational timepiece has been produced and is currently being displayed across the world in the Ships Clocks and Stars: The  Quest  for  Longitude  Exhibition, which started at The  National  Maritime  Museum  and   is currently in Australia.’

‘This project was inspired by Derek Pratt who managed to complete approximately half of the  watch before he became too ill, with prostate cancer, to  continue. Charles Frodsham  & Co  took  on  the  challenge  and  finished  the  project  in  2014.’

‘Every  stage  of  the  whole  reconstruction  was  filmed  and  the story  of  this  remarkable achievement  is now  available  on  a 75min DVD - (PAL/NTSC),. There is a three minute trailer to whet your appetite

‘All profits from the sale of this DVD are being donated to Prostate Cancer UK in memory of Derek.’

To see the trailer and order online go to www.bdvideos.co.uk

Alternately you contact Barbara by email on gordonandbarbara.darby@otford.net or telephone on 01959 523339


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