Portsmouth Naval Base Property Trust creates replica of “CMB4” which sunk Russian warship “Oleg” in 1919 - and it is taking to the Solent today

A six year project has led to the creation of a replica of the CMB4 which was the famous naval craft that sunk a Russian warship in 1919.
By Sophie Lewis
Published 7th Sep 2023, 06:00 BST
Updated 11th Sep 2023, 14:59 BST
Watch more of our videos on Shots! 
and live on Freeview channel 276
Visit Shots! now

The Portsmouth Naval Base Property Trust has spent the last six years researching the CMB4 and a team of 35 dedicated volunteers have spent their time working to make a replica of the famed naval craft.

Today (August 8) the Coastal Motor Boat 4 is taking to the Solent in the form of a fully active and meticulously built replica.

Hide Ad
Hide Ad

It has been 100 years since a coastal motorboat was last active and visitors to Boathouse 4 in Portsmouth Historic Dockyard will have the opportunity to marvel at CMB4R, aka the “Spitfire of the Sea”, following a private launch event hosted today by the PNBPT.

Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: CMB4R on sea trials (above) and CMB4 in action in the early 20th century (image property of the Imperial War Museum)Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: CMB4R on sea trials (above) and CMB4 in action in the early 20th century (image property of the Imperial War Museum)
Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: CMB4R on sea trials (above) and CMB4 in action in the early 20th century (image property of the Imperial War Museum)

The original CMB4 was designed in part by one of the first female members of the Royal Institute of Naval Architects and it is known for sinking the Oleg, a Russian warship, in 1919 as well as being an innovative creation in the Navy.

CEO of the Trust, Hannah Prowse, said: “This replica is the brainchild of Rodney Agar, nephew of the original CMB4’s most famed commander, Lieutenant Augustus Agar. Thanks to funding secured from the Chancellor’s LIBOR fund in 2016, we were able to make Rodney’s ambitious dream a reality despite boat building of this nature being now no longer widely practiced or documented.

SEE ALSO: Portsmouth to limit support it gives to patients being discharged from hospital as it is running out of money

“The influence of the CMB on naval architecture post-WWI is of such significance, it felt only right to recreate this revolutionary vessel so visitors to Portsmouth Historic Dockyard could appreciate and understand its impact.

Hide Ad
Hide Ad
Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. (From right to left) Team lead David Griffiths and volunteers Mike Scott, Hamo Thornycroft, Tim Deacon, Mike Finch and Steve Dawson with CMB4RPortsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. (From right to left) Team lead David Griffiths and volunteers Mike Scott, Hamo Thornycroft, Tim Deacon, Mike Finch and Steve Dawson with CMB4R
Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. (From right to left) Team lead David Griffiths and volunteers Mike Scott, Hamo Thornycroft, Tim Deacon, Mike Finch and Steve Dawson with CMB4R

“We must pay tribute to our wonderful team of volunteers led over the years by David Griffiths, Bob Forsyth and Diggory Rose, our partners Landau, as well as the National Maritime Museum, who provided the crucial plans of the original Coastal Motor Boat from 1915, without which they wouldn’t have been able to build such a high quality replica."

The CMB was designed in 1915 by The Thornycroft Company, a shipbuilder experienced in designing, building and racing high speed boats in the years before the first World War.

Owner, Sir John Isaac Thornycroft and his children, John Edward, Tom and daughter Blanche all contributed to the design of the CMB – but it is only now that Blanche is receiving the recognition that she deserved for the role she played.

Hamo Thornycroft, a former civil architect, marine draftsman and marine photographer is great nephew to Blanche and has been a part of the CMB4R team for almost a year.

Hide Ad
Hide Ad
Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: Blanche Thornycroft holding a recording disc used to test model boats at Steyne House on the Isle of Wight, the Thornycroft family homePortsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: Blanche Thornycroft holding a recording disc used to test model boats at Steyne House on the Isle of Wight, the Thornycroft family home
Portsmouth Naval Base Property Trust spends six years creating a replica of the CMB4R. Pictured: Blanche Thornycroft holding a recording disc used to test model boats at Steyne House on the Isle of Wight, the Thornycroft family home

Hamo said: "It’s only in the last four or five years that historians have become more interested in Blanche Thornycroft and her influence on naval engineering. I think her impact on other women working or aspiring to work in boat engineering can be considerable. The future for women working in this industry is bright. Technical development always requires good minds and in my experience women have these in abundance."