Although Blanche Thornycroft did not keep regular hours at her father's business, it is acknowledged that she made an unsung contribution to the business. She was trained in the same way as an apprentice would be trained and she was known as her father's assistant. Analysis however of correspondence with her brother and father reveal that she was regarded as a maths expert and her work was well regarded. The Thornycroft family home in Bembridge had a model ship testing facility in its grounds, built in 1884, but disguised as a decorative water system known as “The Lilypond”. This was used for complex testing of model ships until 1909, when the need for a larger and indoor test tank was identified. A new test tank, one of the first buildings ever built by pouring concrete over steel, was built at Steyne Woods Battery. The Experimental Boat Testing Tank Facility, at the
Steyne Wood Battery in
Bembridge on the
Isle of Wight, (
Grade II Listed Building Number 1426608) has six angled glazed panels below a concrete walkway, linked to a boiler within the battery to warm water, which was installed by Thornycroft as part of her interest in
hydroponics. Some of Blanche's monographed notebooks, recording her test notes from 1907 until 1939, along with the ship tank models used in her engineering calculations, are held at the
Classic Boat Museum in
East Cowes. The notebooks record her calculations for tests on the models trialled in the lily pond at the family home and later at the Experimental Boat Testing Tank Facility. These models were the basis for the development of Skimmers (racing motor boats), which later evolved into
Coastal Motor Boats. Other models tested ideas for
Acasta and
Acheron Class Destroyers, motor torpedo boats, RAF Rescue Launches, as well as
RNLI Lifeboats. == Royal Institution of Naval Architects ==