Denny Story

Denny Innovation and Experimentation


“The company of William Denny & Brothers has built whole fleets of the finest vessels

afloat” The Bailie, September 1877

The Denny name has been closely associated with the town of Dumbarton since the 1800s. From small beginnings rose a significant shipbuilding firm whose vessels were distinguished, well-respected and innovative. It is this innovation which sets William Denny & Brothers aside from other Clydeside shipbuilders.

The firm was always ‘one step ahead’ and was even working on the development of the hovercraft just before the shipbuilding industry took a sharp downturn, causing Denny’s yard to close its doors for the final time in 1963. This family firm will always be remembered, and its story is one which is interwoven with the development of Clydeside

shipbuilding and its influence world-wide.

Founding the Firm

“The Dennys are almost as closely allied with Dumbarton as is the Castle itself”

The Bailie, September 1877

William Denny & Brothers is celebrated as one of Clydeside’s greatest shipbuilders. The company name goes hand in hand with the town of Dumbarton, and the family’s relationship with shipbuilding started when William Denny (1779-1833) set up a shipbuilding company with Archibald McLachlan in 1814.


Their business was situated at the Woodyard Shipyard on the west bank of the River Leven which flows into the Clyde. Many of the ships they built exemplified the innovation which was to characterise the output of William Denny & Brothers. Denny and McLachlan built a number of `firsts’ including Marjory, the first steamer to ply on the River Thames, Marion, the first steamer on Loch Lomond, and Rob Roy, the first steam vessel for overseas purposes.

The shipbuilding company traded under many different names before the firm of William Denny & Brothers was properly established. In 1823 the firm became known as William Denny & Son and used this name until 1838.

A Family Firm

William’s six sons followed him into shipbuilding. Denny Brothers was founded in 1844 by his third son, also William (1815-1854), in partnership with three of his brothers, James (1807-1864), Alexander (1818-1865) and Peter (1821-1895). The brothers focused on maritime architecture and were initially based in Glasgow. However Denny Brothers was soon back in its rightful home in Dumbarton when the brothers took up the lease of the small Kirk Yard on the banks of the Leven.

They devoted themselves to shipbuilding and their first contract was awarded in 1844 for the paddle steamer Lochlomond. This vessel, built for the Dumbarton Steamship Company, is listed as the firm’s yard number 1 – its first ‘official’ ship.

In the years following the move the firm’s relationship with Dumbarton strengthened and grew. Almost everyone in Dumbarton had some sort of link to the firm, which, in 1849, became known as William Denny & Brothers. In 1850 the engine works of Tulloch & Denny (later Denny & Company) was set up by Peter Denny, John Tulloch and John McAusland. This helped with the firm’s expansion and development as it no longer needed to send its hulls elsewhere to be engined.


“Denny’s is Dumbarton and Dumbarton is Denny’s”

Charles Mclivenna, July 1961

During the 1850s the town increased rapidly in population and prosperity due to the development of the firm. William Denny built a series of workmen’s dwellings to properly accommodate the townspeople, an early example of how the Denny firm had the interests of its workforce at heart. However, the death of William Denny in 1854 was a major blow as he had done so much to revive the fortunes of Dumbarton. The firm was left in the charge of James and Peter Denny, with Peter becoming the sole partner in 1862. Fortunately he exhibited the same foresight his brother had shown, and under his leadership the firm went from strength to strength.

As the firm grew it began to build an assortment of vessels. In 1863 the shipbuilding boom caused by the American Civil War reached the Clyde. The Confederacy required fast `blockade runners’ to steam through the Union blockade to the Southern ports. William Denny & Brothers built several of these vessels which delivered food, clothing and weaponry to the Confederate forces.

The firm expanded under the leadership of Peter Denny and began to build larger ships. In 1867 the whole shipbuilding operation moved to the well-equipped Leven Shipyard, and in 1869 it completed and launched Cutty Sark after Its original builders went bankrupt. Peter Denny became one of the leading figures in the shipbuilding world and was made an honorary LL.D. (Doctor of Law) of the University of Glasgow in 1890. As well as being a renowned figure in the local community he received honours from the governments of Belgium, Portugal and Spain.

The Napier Connection

A number of Denny Directors learnt their trade at the shipyard of Robert Napier, widely regarded as “the father of Clyde shipbuilding”. Napier was from a Dumbarton family and was a pioneer who did a great deal to establish travel by steam – rather than sail – as a reliable means of crossing the world’s oceans. Has first marine steam engine from Leven of 1823 can be seen outside the Denny Tank building. In 1842 William Denny (1815-1854) was engaged by Napier as manager of his shipyard at Govan. and his brother Peter was employed as his assistant. Walter Brock served his apprenticeship with Napier’s company and was later employed as a draughtsman and Engine-Works manager before making a natural progression to William Denny & Brothers.

A Scientific Approach

Peter Denny gave his sons a practical training in the yard, and in 1868 his eldest William (1847 – 1887) became a partner. William became the firm’s greatest innovator before his suicide in 1887. His contribution ensured that Denny’s was one of the most scientific shipbuilding companies in the world.

Among his achievements was the introduction of progressive speed trials over the measured mile, the building of the first commercial test tank, the construction of ships with double bottoms, and the use of mild steel for shipbuilding purposes. He also made great progress in the field of industrial relations by being one of the first to employ women in the drawing office. He was an approachable employer and workers benefitted from rewards, schemes and scholarships. As his nephew Maurice Denny later said, “he was a generation ahead of his time”.


In 1894 the Firm celebrated the fiftieth anniversary of its founding with a special gathering. Unfortunately the following year Peter Denny died, and his contribution to shipbuilding was marked with the erection of a bronze statue in his likeness, which can still be seen outside Dumbarton’s Municipal Buildings today.

The firm continued to prosper with a new generation in charge. Peter’s sons became partners and the years 1896 to 1906 saw great technical energy and expansion. This was partly due to the firm’s involvement in the development of turbine machinery which revolutionised shipbuilding, with Denny building the first turbine-powered passenger steamer, TS King Edward in 1901.

Highs and Lows

“In good times and in bad there has been one guiding principle, to produce the best” Denny Centenary Booklet Peter Denny’s son Archibald (1860-1936) became chief designer and was responsible for many of the vessels of the period. Under his guidance great developments were made in the construction of cross-channel steamers for which the firm was famous. His good work was continued by his son Maurice (1886-1955), who became a partner in 1911, a few years after the shipbuilding and engineering sides of the shipyard legally amalgamated. He saw the company through the difficult years after the two World Wars and ensured that they remained innovative via the jet-engine experiments carried out on Lucy Ashton and the development of the Denny-Brown stabilisers which reduced the rolling of ships.

Sir Maurice, who had succeeded to his father’s baronetcy in 1936, retired in 1952 and was replaced by his cousin Edward. The company’s pioneering spirit was not forgotten as it was working on the development of the hovercraft just before it closed in 1963. The closure was a shock to many, who were surprised that the most innovative of the Clyde shipbuilding firms was one of the first to close its doors.

Join us now as we explore some of the firm’s foremost innovations and take a closer look at their legacy.

“There is usually no surer way to kill a family business than to admit to the direction thereof only the sons of the founder and their sons” Sir Maurice Denny, 1938

William Denny & Brothers was very were much a family firm. However, many non-Dennys were admitted to the Board and their skills and expertise contributed to the company’s success. Some of the names who feature include John McAusland, one of the founders of the Denny Engine Works, Walter Brock who had been Engine-Works Manager at Messrs. R Napier & Son, John Ward who joined the firm as Chief Draughtsman, and Daniel Jackson took over Ward’s later role as General Manager.

Irrawaddy Flotilla Company

“Come you back to Mandalay, Where the old Flotilla lay: Can’t you ‘ear their paddles chunkin’ from Rangoon to Mandalay?”

Rudyard Kipling ‘Mandalay’, 1910  

The Irrawaddy Flotilla Company was founded in 1865 in Burma (Myanmar) and at its peak in the 1930s operated over 600 vessels which carried nine million passengers a year along the Irrawaddy River. The Denny association with the company is notable and Peter Denny’s contribution enhanced the fortunes of both the Flotilla Company and William Denny & Brothers.

The Irrawaddy Flotilla Company was a Scottish venture set up by the partners of P Henderson & Co, Todd. Findlay & and Peter Denny to transport passengers, mail and cargo along Burma’s great river highway. Peter Denny was also a leading shareholder in Henderson’s Albion Shipping Company, and his new interest in the Irrawaddy Flotilla Company proved very beneficial. William Denny & Brothers was soon the main builder of the shallow-draught paddle vessels which were built in Dumbarton, dismantled, shipped to Burma in Henderson Line ships, then re-assembled and launched at Darla shipyard on the banks of the Irrawaddy.

At its peak, the Irrawaddy Flotilla Company operated the largest fleet of ships in the world. Unfortunately this once proud fleet was a victim of the `Burma Campaign’ of World War II. In 1942 Japanese troops invaded the country and almost all of the company’s 600 vessels were deliberately sunk by their owners to spite the enemy: a sad end for the ‘greatest river fleet on earth’.

Denny Ship Model Experiment Tank

“It was the happiest place I ever worked in; there was a definite team atmosphere”

John Blevins, Naval Engineer 1949-1959

The Denny Ship Model Experiment Tank was the world’s first commercial example of a test tank and was the starting point for many of the firm’s great innovations. The idea of a tank was first developed by William Froude who built a test tank for the Admiralty in Torquay in 1871. William Denny was impressed with this scientific technique and persuaded the firm’s partners to construct a tank in which they could conduct their own experiments.

The Tank was completed in 1883 and was designed to test scale models to determine the most efficient hull shape and power requirement for any particular vessel. These small-scale tests were used to predict the behavior of full-sized hulls. More value was added to the tests in 1887 when a wave maker was installed to simulate rough seas.

Throughout its working life the Tank tested models of a variety of vessels and explored various propulsion methods, including propellers, paddles and vane wheels. Experiments were carried out on models of the Denny-Brown stabilisers and the hovercraft to gauge their feasibility. Tank staff also carried out research and experiments for other companies. Belfast-based Harland & Wolff decided to fit a bulbous bow on Canberra after successful model tests in the Denny Tank.

The success of the Denny Tank inspired other shipbuilders and scientific bodies to build their own tanks. Notable tanks were built at the University of Glasgow and St Albans and these are still in use today.

The Denny Helicopter

“The combined efforts of a squad of men were necessary to prevent its disappearing with an intrepid member of staff as pilot”

The Denny Book, 1932

In 1905 Tank Superintendent Edwin Mumford and his chief assistant, J. Pollock Brown, started experiments using propellers to lift a machine into the air. They experimented with model screw propellers under water in the Experiment Tank and adapted the results to see how a machine would work in the air.

The first machine had a bamboo framework with six propellers mounted on the sides. The engine and pilot’s seat were situated in the middle of the apparatus. The propellers were driven by chains and extension shafts and the only control was from a rudder at the rear of the frame.

The first test flights were made in 1908, but failed as the engine was unreliable and heavy. A more powerful engine was purchased and a new aluminum frame built. The machine rose to the air-under its own power on 7 September 1912. In 1914 a final version fitted with floats was said to have been successfully tested on the river, but was later destroyed in a gale.

The outbreak of World War I in 1914 meant that further development was halted. Nevertheless Denny’s ensured that it was ahead of its time by producing what is believed to be the first helicopter to leave the ground under its own power.


“There was so much work to be done for the Admiralty that we were really seconded into war service”

William Walker, Tank Superintendent, World War 2

William Denny & Brothers was well known for the production of fast, reliable warships. Up until 1905 the firm was unable to produce vessels for the British Admiralty as one of its partners was a Member of Parliament. In 1905 the partner resigned his seat and the firm was place on the Admiralty list of shipbuilders.

The firm’s experience of building pioneering turbine driven steamers was put to good use during World War 1 as it delivered a torpedo boat destroyer every eight weeks. It also built other vessels and three ‘E’ class submarines.

During World War 2 William Denny & Brothers built destroyers, anti-aircraft escort sloops and minesweepers. One of its many innovations of the period was the development of steam gun boats which were small fast vessels designed for coastal warfare. In 1941 the company built SGB 7 and SGB 8, both gun boats which used steam rather than petrol as fuel to reduce the risk of explosion.

The company remained experimental throughout the war years. The Tank was kept very busy and a great deal of work was done on the development of MTB 109. This was a very fast motor boat designed to travel at speeds of up to 60 knots and keep up with enemy E-boats. It was handed over to the Admiralty towards the end of World War 2.

Denny Brown Stabiliser

“We did a run along the Tank one evening, when the model was rolling violently… We succeeded in stabilising it completely, which was quite a historic occasion”

William Walker, Tank Superintendent

One of the most revolutionary innovations in the shipbuilding world was pioneered by William Denny & Brothers. The idea of ship stabilisers was not entirely new as it was first patented in 1898 by a Sterling based chemist and implemented by Dr Shintaro Motora in 1920. However it was the Denny’s which made a real success of the product when Sir Maurice Denny collaborated with William Wallace from Edinburgh based Brown Brothers to develop the Denny Brown Stabiliser in the 1930s.

The stabiliser was designed to reduce the roll of ships when travelling through heavy seas. It works by using two fins which move up and down like the flaps of an aircraft wing to counteract the effect of waves on the hull. The fins are controlled by a gyroscope and are housed within the hull when not in use.

Stabiliser models were tested extensively in the Denny Tank. The first ship to be fitted with Denny-Brown stabilisers was the passenger ferry Isle of Sark in 1938, and they were soon fitted to naval and merchant ships worldwide. In 1955 stabilisers were fitted to Cunard’s Queen Elizabeth, but not to Queen Mary because the owners thought she was too old. The result was that people were reluctant to travel on Queen Mary because of her instability, so she too was fitted with stabilisers in 1958. This was very important as during this period sea travel was facing competition from air travel, and passenger shipping companies needed their vessels to be as comfortable as possible.

Over the years stabilisers have improved and have become a standard feature of comfortable sea travel.

The Denny Hovercraft

`It was a beautiful thing to run and it was really quite an experience when you switched on the fan and you felt it coming up…then they would switch on the outward motion and it just took off’

Dr Robert Davidson, member of hovercraft design team

In the 1960s William Denny & Brothers was at the forefront of the push to develop the hovercraft. It was one of four firms collaborating with Hovercraft Development Ltd. on the design of this exciting new form of sea travel. The hovercraft was designed to travel over a smooth surface supported by a cushion of slow moving, high-pressure air ejected downwards. This was contained within a sidewall or ‘skirt’.

After a series of tests on models in the Experiment Tank a prototype, made of plywood and sheet metal, was built. This vessel, known as D1, was powered by two outboard engines which propelled it at speeds of over 18 knots during trials on Gareloch on Jun 22nd 1961.

Denny’s formed a subsidiary company, Denny Hovercraft Ltd, to deal with this new venture. The company launched a full sized passenger carrying version, D2-002, in 1962. In 1963 this sidewall ‘hoverbus’ made the 820 mile journey from Dumbarton to the River Thames where it was demonstrated. This was not a great success as floating debris damaged the vessels skirts and propellers, though it did show promise.

This was one of the firm’s last major projects before it closed its doors in 1963. An attempt to save the hovercraft venture was made after the firm went into liquidation but limited progress was made.

Have a look at the video clip to see D2-002’s voyage from Dumbarton to the River Thames.