Gunboat Traverser System


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:
Location Description:
Gunboat Traverser System, Haslar Gunboat Yard, Haslar Road, Gosport, Hampshire


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The building or site itself may lie within the boundary of more than one authority.

Location Description:
Gunboat Traverser System, Haslar Gunboat Yard, Haslar Road, Gosport, Hampshire
Gosport (District Authority)
Non Civil Parish
National Grid Reference:


The remains of the gunboat traverser system beneath and in front of the gunboat sheds, 1856.

Reasons for Designation

The gunboat traverser rails and remains of the slipway, of 1856, are scheduled for the following principal reasons: * Period: built to house and mobilise the fleet of gunboats found invaluable during the Crimean War, the remains of the traverser system including the slipway are thought to be unique in a naval context and hence representative of a significant period of naval defence; * Rarity: one of few structures built resulting from the Crimean War, and the earliest surviving example of a steam-powered traverser system; * Documentation: well-documented through primary and secondary sources, in which the aesthetic, technical, military and political aspects of the site and period are recorded; * Group value: the traverser system is the principal element of the site, and is associated with a number of other highly-graded listed buildings including the gunboat sheds; * Survival and potential: the remains of the traverser system in front of the sheds survive well below ground and have the potential to illustrate the mechanical operation of the system.


Haslar Gunboat Yard at Gosport, Hampshire is thought to be a unique naval site. It operated as a yard for the housing and repair of British gunboats between 1856 and 1906, and subsequently for the gunboats' successors and other naval craft. The site comprises a series of original iron sheds for housing the gunboats, part of the traverser system used for their launch and movement and a collection of ancillary buildings relating to repair, maintenance and power provision both for the gunboat yard and the Royal Naval Hospital, Haslar on the opposite side of Haslar Road. The site is bounded by high walls with sentry posts, and has a guard house and police barracks.

The Portsmouth region has a long association with naval defence, thanks in part to its easily defensible natural harbour. A Norman motte and bailey towards the western side of the Gosport peninsula attests to a long history of occupation and awareness of the defensive characteristics of the area. Portsmouth had ‘the merits of a good sheltered harbour, the proximity of the New Forest as a source of ships’ timber, and a reasonable communication with London’ (Coad, 1989). The Earl of Sandwich wrote that Portsmouth was better able to be secured and defended than Plymouth and that ‘Portsmouth is more central and happily situated for facilitating a junction of our ships from Eastward and Westward with a spacious and safe road for the rendezvous of the whole fleet’ (Coad, 1989).

The Royal Navy was responsible for much of the development and infrastructure of the Portsmouth area. There were supplementary sites such as the Royal Clarence Victualling Yard and the Haslar Hospital, but the development was focused around the shipbuilding, repair, maintenance, and storage of the Navy’s fleet. This activity occurred largely in the Portsmouth Dockyard, which sits to the east of the main natural harbour. These developments meant that Portsmouth was for a long time one of the most heavily fortified towns in Europe, the defences entirely due to the importance of the naval base. As the principal naval port Portsmouth was consistently at the forefront of innovation and development.

The British gunboat fleet was developed in the 1850s with the Crimean War (1853-56); they were small, steam-powered craft with one gun, ‘light, swift, commodious, well-armed, easily handled, independent of wind and tide, and capable of acting separately or in concert’ (Mechanics’ Magazine, 1857) and it was thought, at the time, that they would always be of use in the British Navy. Although in use by a number of countries, the gunboat had peculiarly British associations due to its widespread use across the globe, giving rise to the phrase ‘Send a Gunboat!’. Initially gunboats were built of timber but by the 1870s composite boats of timber and iron were being constructed; by the C20 these vessels were made entirely of steel. Due to the nature of naval warfare being conducted, gunboats were ordered in large quantities during the 1850s and into the 1860s.

Following the Crimean War, it was deemed that a ready fleet of gunboats was necessary to ensure the safety of the English coast. Unlike their larger counterparts, gunboats were too small and too numerous (c120) to hold in existing dry docks in naval ports such as Portsmouth and as a result they were frequently left at sea. Their iron parts, which included hulls, engines, and boilers, along with the frequent use of unseasoned timber, meant that storage afloat was not practical. The solution was to construct a separate yard where such vessels could be stored and repaired on dry land, potentially for long periods of time, whilst remaining seaworthy and ready for action.

Although a number of sites were considered for the yard, including Chatham Dockyard, Royal William Victualling Yard at Stonehouse, Plymouth, and Keyham Yard at Devonport Dockyard, the final decision rested on Haslar. The site chosen was to the north of the hospital, bordering Haslar Creek, the waterfront access along the northern boundary enabling ease of launching vessels at high tide. Maps from the early nineteenth century show that the site was undeveloped farmland prior to the Navy’s leasehold.

The biggest challenge in the yard’s construction was providing a means by which boats could be easily hauled up and stored, and equally, removed from storage for active service in a timely fashion. The solution was a steam-powered traverser system, complete with slips, that allowed boats to be hauled up and moved parallel to the waterline before being placed in a storage shed. An earlier traverser system, possibly the first in Britain, was used in the Swindon Railway Works and shows similarities with the design employed at Haslar, but is no longer extant. The traverser at Swindon was conceived by Daniel Gooch, appointed by Isambard Kingdom Brunel as the superintendent of locomotive engines in 1837, and has a construction date of 1842.

Newspaper reports from the period have conflicting information about who was responsible for the design. The overall designs for the gunboat yard were undertaken by the Admiralty Works Department, under Colonel GT Greene, the Director of Works and William Scamp, the Deputy Director of Engineering and Architectural Works, and it is believed to be primarily Scamp’s creation. However, Mr White, Jr., of Portsmouth, is credited in one newspaper report for the design of the system, though he is likely only to have been responsible for the design of the cradles used to transport the boats along the rails.

Scamp had exhibited a model for a hauling-up yard at the Great Exhibition in 1851. The model was for an unsuccessful 1849 scheme designed to haul ashore the largest warships, and it is highly probable that this was the basis for the design employed at Haslar. Scamp was a self-taught architect who, in 1837, became assistant engineer at Woolwich Dockyard. He began his naval career in Malta, where he was responsible for the design and construction of a large number of buildings. His success in this post meant that upon his return to England he was made Deputy Director of Engineering and Architectural Works to Colonel Greene. In this role he oversaw a number of developments within the English ports, not least of which at Portsmouth.

The gunboat yard was a project of great magnitude, with at least five contractors, each the most eminent in their field, employed to do the work. The iron rails were entrusted to Messrs Fox and Henderson, who worked on the Crystal Palace and had undertaken work on naval slipways prior to the construction of the gunboat yard. The construction of cradles on which the vessels were to be conveyed was by Mr White, Jr., of Portsmouth, well-known for his experience on slipways. Mr MacDonnell was the Admiralty’s Superintending Engineer. The Government contributed, too, permitting the use of the timbers from recently broken up men-of-war for sleepers for the rails.

The traversing system was described in the Hampshire and Sussex Telegraph in 1856 as having a triple row of rails from the shore, meeting at right angles with a row of seven rails to traverse the boats parallel with the shore, then, again at right angles, rows of rails leading into the boats’ separate berths. The traversing rails were c35m wide and c425m long, and could be extended as required.

The first vessel, ‘the Gnat’, was hauled up on 25 November 1856, just five months after the Navy had approved the choice of site. It was not entirely successful due to insufficiently powerful machinery. After amendments were made, the system was successfully demonstrated in January 1857, when the ‘Cherokee’ was launched. A steam locomotive named ‘The Elephant’ was installed in 1858 to move the boats along the transverse slipway.

By 1859 there are known to be 40 sheds. In the early 1860s a further ten sheds were erected, as well as a new jetty and crane at the north-east of the site, assisting with repairs and lifting heavy machinery without the need to remove boats from the water.

Following the end of the war and the inspection of gunboats it emerged that a great number had been hastily built, often using green timber and insufficiently-long copper bolts. Those considered irreparable were condemned to be broken up, whilst others were sold, or converted to coal depots. A vastly diminished number were retained to form the reserve. As a result, later in the 1860s the traverser system was shortened and 40 of the 50 sheds were moved to the Portsmouth Dockyard. The yard was put up for let in 1870, though it is known, by 1871, to have been back in use for the storage of gunboats: a new fleet of iron vessels was commissioned, and new sheds were erected for their storage; these have not survived. At the same time as this early-1870s refitting the creek was dredged and plans suggest a jetty extension and reconstruction. By 1906, however, gunboats were considered obsolete naval technology and all had been scrapped or retired due to maintenance costs and the advent of new, smaller craft. The changing role of gunboats had implications for the use and layout of the yard. It continued in general use through the First and Second World Wars for the service and repair of naval craft, including motor torpedo boats, the gunboats’ successors. From 1939 until 1956 the eastern part of the site was part of HMS Hornet, the Coastal Forces Patrol. In 1955 a new slip was built, and the original steam locomotive, the Elephant, replaced with an electric version. The two-storey brick structure in the seventh bay of the sheds is likely to date from this period. Following the de-commissioning of HMS Hornet the site gradually went into use as a mooring yard for naval personnel, and in 1964 was officially opened as a naval yacht club. The rails embedded on either side of the 1955 slip appear to date from this period of use. In the 1970s, the traverser system was abandoned, and the cradles and other machinery removed. The new Haslar bridge, opened in 1978, prevented large craft accessing the yard. Many of the sheds were removed in the 1980s and 90s. The south-west of the yard began to be used for the Admirality's experimental works from the late C19. Since 2001 the south-western part of the site has been in use by a naval defence contractor, and the north-eastern part remains in use as a sailing centre.

In 2014 trial trenches were excavated to establish the survival of the main traverser rails in front of the gunboat sheds. It confirmed the presence of a row of seven rails buried at a depth of 1.2m.


PRINCIPAL ELEMENTS: the buried remains of the gunboat traverser system in front of the gunboat sheds, and the remains of the slipway, of 1856. The design of the gunboat yard was by the Admiralty Works Department, under Colonel Greene, the Director of Works and William Scamp, the Deputy Director of Engineering and Architectural Works. The supply of the rails was contracted to Fox and Henderson of London. The traverser system comprises rails to transport vessels between the water of Haslar Creek and the gunboat sheds, and associated fixtures. DESCRIPTION: the rails of the original slipway have been removed at the top, though appear to remain at the waterline. These would have joined the central transverse slipway: a sunken row of seven rails running parallel with the creek and the gunboat sheds. The transverse slipway adjoins perpendicular rows of six rails leading into each shed (the sheds are listed at Grade I, reference 1431190).

EXCLUSIONS: the chain-link fences bounding the site are excluded.


The contents of this record have been generated from a legacy data system.

Legacy System number:
HA 505
Legacy System:


Books and journals
Coad, Jonathan (Author), Support for the Fleet - Architecture & Engineering of the Royal Navy's Bases 1700-1914, (2013)
Coad, J , Historic Architecture of the Royal Navy, (1983)
Coad, J G, The Royal Dockyards 1690-1850: Architecture and Engineering Works of the Sailing Navy, (1989)
SAVE Britains Heritage, , Deserted Bastions, (1993), 93
Jonathan Coad, ‘Appendix IV: History of Haslar Gunboat Yard’, in [A. Kelly & Jon Gill], Guardrooms, Haslar Gunboart Yard, Gosport. Buildings at Risk II Survey (Unpublished Oxford Archaeology report for Defence Estates, 2007).
O Hickson, 2012 A Study of Haslar Gun Boat Yard with New Insights into Its History, Construction, Manufacture and Use. Unpublished MSc Building Conservation: Weald and Downland Open Air Museum with Bournemouth University
'Our Gunboat and Mortar-Boat Flotilla', Mechanics' Magazine, 3 January 1957, 5
Sarah PC Hendriks, Haslar Gunboat Yard, Gosport: Historic Buildings Report, 2014. Available at:


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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