Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains

Rangitane Road (State Highway 56), Opiki

  • Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains viewed from east side of the Manawatu River.
    Copyright: NZ Historic Places Trust. Taken By: Karen Astwood. Date: 2/08/2013.
  • Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains.
    Copyright: NZ Historic Places Trust. Taken By: Karen Astwood. Date: 2/08/2013.
  • Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains. Image courtesy of Palmerston North City Library Ref. 2011N_FX118_004647.
    Copyright: Palmerston North City Library.

List Entry Information

List Entry Status Listed List Entry Type Historic Place Category 1 Public Access Private/No Public Access
List Number 9619 Date Entered 31st October 2013

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Extent of List Entry

Extent includes part of each of the five land parcels described as Lot 6 DP 10695, Pt Aorangi 3 3H9, Lot 5 DP 10695 (NZ Gazette 1963, p. 590), Lot 1 DP 27040 (NZ Gazette 1991, p. 1692), and Pt Lot 1 DP 9314 (NZ Gazette 1959, p. 723), Wellington Land District, and the structures known as Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains thereon. (Refer to map in Appendix 1 of the registration report for further information).

City/District Council

Horowhenua District

Region

Horizons (Manawatu-Wanganui) Region

Legal description

Lot 6 DP 10695, Pt Aorangi 3 3H9, Lot 5 DP 10695 (NZ Gazette 1963, p. 590), Lot 1 DP 27040 (NZ Gazette 1991, p. 1692), and Pt Lot 1 DP 9314 (NZ Gazette 1959, p. 723), Wellington Land District

Location description

This registration is located within both the Horowhenua District Council and the Manawatu District Council area boundaries. The remains can be seen at Opiki, when travelling along State Highway 56 between Makerua and Palmerston North, which is where the highway crosses the Manawatu River. There is limited space to park on the shoulder of the highway. There is no direct public access to the structures.

Summaryopen/close

Once part of what was New Zealand’s largest commercial flax industry when they were completed in 1917-18, the concrete remains of the Tane Hemp Company Limited Suspension Bridge and Flaxmill is now a prominent landmark on the Manawatu River at Opiki.

One of New Zealand’s earliest export products, during the opening decades of the twentieth century flax fibre made a key contribution to the national economy. There were many flax growing regions, but the Manawatu and Horowhenua were notable from the 1860s. In particular, the Makerua Swamp stretching between Linton and Shannon was an important centre, and its production peaked during World War One making it New Zealand’s largest commercial flax production area.

Members of the prominent local flax industry families, the Seiferts and Akers, combined forces with other investors in 1915 to form the Tane Hemp Company Limited. Access to the local railway station was problematic, so roads through the swamp, and means of crossing the Manawatu River, were soon devised. This included the company’s significant investment in a suspension bridge, designed by the prolific Pahiatua bridge builder, Joseph Dawson. The company also upgraded its mill facilities in 1918 with a replacement concrete chimney for its steam engine exhaust. However, a devastating flax disease compounded the post-war slump in demand, and by the early 1920s the Tane mill had closed, like the majority of its local counterparts. These mills were then demolished and the swamp drained to create farmland. The suspension bridge passed into sole Akers family ownership, and soon a toll began to be charged to contribute to the structure’s maintenance. In 1969 a replacement state highway bridge was constructed and the decking of the suspension bridge was removed.

The mill and bridge remains are located on a pastoral flood plain. The structures consist of concrete bridge towers, with suspension wires and hangers dangling between, and the nearby concrete flaxmill chimney, which is approximately 20 metres high, and a boiler pad at its base. These structures no longer have a functional purpose, but have been left as monuments to the local flax industry.

The Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains have special significance for their ability to represent New Zealand’s flax production industry, which was of particular importance to the national economy in the early twentieth century. These are landmark structures that are the only substantive vestiges of a formerly defining regional industry. The structures are significant representative examples of the industry because they are located in what was New Zealand’s largest commercial flax production area, they were built during the industry’s boom period, and because they are now the most intact structures that remain of the industry in what was once the country’s centre for flax production. The suspension bridge retains special historical and technological value as a rare surviving example of Dawson’s work, a relatively early use of reinforced concrete in a New Zealand bridge, and because it was one of the largest bridge main spans ever constructed in New Zealand. After the collapse of the flax industry, the bridge gained distinction as the only privately owned toll bridge in this country’s highway network.

Assessment criteriaopen/close

Historical Significance or Value

Having been one of the earliest industries in the Manawatu and northern Horowhenua, flaxmilling went through several boom periods before peaking during the period that the Tane Hemp Company Limited began operating. This company, associated with leading local industry families the Seiferts and Akers, contributed to the Makerua Swamp’s national reputation as the most lucrative flax production area. The remains of this company’s facilities have special historic importance as reminders of one of New Zealand’s largest flaxmills, constructed during the industry’s highpoint, which came to an abrupt end due to the combined effect of a post-World War One slump in demand and a devastating flax disease. The bridge and flaxmill remains are the only substantive evidence of the formerly important local hemp industry. They have been a constant feature, overseeing the major 1920s change in the landscape which saw it turned from swamp into pastureland.

After flaxmilling in the immediate area ceased, the suspension bridge gained a profile as the only private toll highway bridge in New Zealand until 1969. Owned by the Akers family, the structure was the subject of decades of deferment by the Public Works Department despite pressure from its Minister, Robert Semple, and the motoring public, to create a public bridge for the highway established in 1937. Therefore, the bridge remains have a special place in the motoring and road infrastructure history of New Zealand.

Aesthetic Significance or Value

The Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains have special aesthetic value as highly visible sculptural features within their landscape, that stimulate the interest of passers-by. The landmark qualities of the structures mean they are inextricably linked with Opiki and have been iconic aspects of the district for almost a century.

Archaeological Significance or Value

The Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains include structures and subsurface features related to a regionally and nationally important late nineteenth and twentieth century industry. There is potential for archaeological material that can contribute to the understanding of the facilities and technologies involved in flax growing and milling, and as such this place has archaeological value.

Technological Significance or Value

The Tane Hemp Company Limited’s suspension bridge, designed by well-known bridge-builder Joseph Dawson, has outstanding technological significance as the vestige of one of the longest main span bridge’s ever constructed in New Zealand. The high reinforced concrete towers enabled the successful creation of this span, and also indicate the rapidity with which their material was embraced by New Zealand bridge builders in the early twentieth century. While the deck was removed in 1970, the span’s impressive scale can still be appreciated because of the retention of the bridge’s towers and catenaries. This structure represents the zenith of suspension bridge building in New Zealand.

Social Significance or Value

The flax industry had considerable economic and social impact in the Manawatu from early in the history of European settlement and into the twentieth century. This primary industry motivated the construction of infrastructure to penetrate the Makerua Swamp, which resulted in enhanced transport and communications in the formerly isolated area between Palmerston North and Shannon. The Tane Hemp Company Limited’s structures have a direct link to this, because the suspension bridge was an essential component of a road originally developed to facilitate the associated important flaxmill’s productivity, that because of its transport significance later became a highway.

This place was assessed against, and found to qualify under the following criteria: a, b, e, f, g, and h. It is considered that this place qualifies as a Category 1 historic place.

(a) The extent to which the place reflects important or representative aspects of New Zealand history

Flaxmilling was a significant early primary industry in New Zealand, and one intimately linked with the social and economic development of the Manawatu and north Horowhenua. Although the industry had a foothold in many regions nationally, it was here that it particularly thrived. More specifically it was the Makerua Swamp, where the Tane Hemp Company Limited established itself, that became the largest commercial flax swamp in New Zealand during the peak production period, 1910-1918. As remnants of the operations of one of the principal flaxmills in the country, the Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains are of special significance for their direct link to this aspect of New Zealand’s history, as well as telling of the disastrous effect that the diminished demand for flax products, and the yellow-leaf disease, had on the industry.

(b) The association of the place with events, persons, or ideas of importance in New Zealand history

Although not much physical evidence remains, Joseph Dawson was a prolific and prominent New Zealand bridge designer and contractor in the late nineteenth and early twentieth centuries. Dawson specialised in suspension bridges, even patenting a construction techniques and design features. Completed five years before his death, the Tane Hemp Company Limited’s suspension bridge can be considered Dawson’s crowning achievement and a rare surviving remnant of his once considerable oeuvre.

(e) The community association with, or public esteem for the place

Once part of, and now located beside, State Highway 56, the Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains are landmarks with strong community associations. When part of the road network, the bridge was a novelty for tourists, and the flaxmill remnants were an added point of interest. In spite of the highway’s deviation, these prominent structures have continued to be valued, as is shown by their retention and the information cairn and plaque on the side of the highway, placed there by local heritage advocates who also published a book on the topic.

(f) The potential of the place for public education

There have been many local publications specifically on, or that feature, the importance of the local flax industry in the Manawatu region. The Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains are the most substantial and accessible physical vestige of this, and therefore of educational value. Moreover, even at a distance the remnants draw people’s attention and curiosity and are therefore an excellent way of introducing people to this aspect of the region’s history.

(g) The technical accomplishment or value, or design of the place

The suspension bridge remnants convey the technical accomplishment and design value. The bridge was recognised as an engineering achievement because of its span length, and also as an attractive and impressive structure, when it was constructed. Reinforced concrete, which at the time was only just immerging as a popular bridge material in New Zealand, enabled for the towers to be high enough to correspondingly allow for the bridge’s impressive span.

(h) The symbolic or commemorative value of the place

The Tane Hemp Company Limited’s Suspension Bridge and Flaxmill Remains are extant because the Akers family believed in their commemorative value as symbols of the area’s extinct flax industry of the late nineteenth and early twentieth centuries. The company’s former structures serve as a superlative local reminder to this formative industry, especially since the draining of the swamp has altered the landscape to the extent that this history is not easy to read.

Summary of Significance or Values

The Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains have special heritage significance for their ability to represent New Zealand’s flax production industry. Prominent within their landscape, these structures are a tribute to the flax industry that was historically, socially, and economically important to the national economy in the early twentieth century. The industry was centred in the Manawatu and Horowhenua regions andthese landmark structures are now the region’s only substantive vestiges of what was a formerly defining regional industry. They were constructed by the Tane Hemp Company Limited, which had one of the principal mill operations in the Makerua Swamp, which in turn was New Zealand’s largest commercial flax swamp. These structures are recognised as the best monument to this industry due to their location in what was New Zealand’s largest commercial flax production area, their construction during the industry’s boom period in the opening decades of the twentieth century, and because they are now the most intact structures that remain of the industry in what was once the country’s centre for flax production. They therefore have special significance. The concrete chimney was a nationally unique aspect of the mill facility, as was the company having its impressive suspension bridge as an asset, which also became notable as the only privately owned toll highway bridge in New Zealand. Indeed, this structure is testimony to the scale of the Tane Hemp Company Limited’s enterprise, and the skill of prominent bridge-builder Joseph Dawson who, with his Opiki bridge, created an engineering achievement because it was one of the longest main span bridges ever constructed in New Zealand.

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Construction Professionalsopen/close

Dawson, Joseph (1843-1923)

Born in Tasmania, Dawson came to Christchurch at age 26 where he was engaged as a carpenter apprentice. After gaining experience erecting railway bridges he moved to the Wairarapa, living in several places before finally settling in Pahiatua in 1889. Here Dawson farmed but also became a renowned bridge designer and builder, being responsible for several early twentieth century Hutt River bridges, as well as structures in the Manawatu and in many in the Wairarapa. He specialised in suspension bridges and was granted patents on several construction and design aspects which seem to have contributed to what was referred to as the ‘Dawson system.’ These bridges range from small private farm structures to monumental bridges like the Tane Hemp Company Limited’s bridge at Opiki. Despite being prolific, it seems that few physical legacies of Dawson’s work remain, with the exception of the Opiki bridge’s towers and catenaries and the concrete towers of the Mokai Bridge across the Rangitikei River.

Additional informationopen/close

Historical Narrative

Beside the Manawatu River in what was the Makerua Swamp, there are archaeological sites indicative of Maori settlement and activity in the area, including Ngati Raukawa graves, ovens and midden. Indeed, Opiki continues the name of a kainga which was located there previously. Historical records indicate that local Maori lived in and around the Makerua Swamp from at least the mid nineteenth century. The swamp area was external to negotiations between Ngati Raukawa, Rangitane, and the government in the 1860s, because it lay between the boundaries of the Horowhenua, Rangitikei-Manawatu, and Te Ahuaturanga blocks. The ‘great swamp’ encompassed an area stretching from present day Linton almost as far south as Shannon, and inland from the Tararua Ranges to the Manawatu and Oroua Rivers.

In general, New Zealand harakeke/flax fibre produced by Maori began being exported during the 1820s. In the Manawatu/Horowhenua region most of this activity seems to have been centred further southwest in the Moutoa Swamp and Foxton. It is unclear how extensive Makerua Swamp flax production was in the mid 1800s because it appears that conditions were more suited to raupo than harakeke. The relatively limited nature of the Makerua Swamp industry during this period is inferred by 1880s land sales advertisements not promoting any economic potential in terms of flax production.

It was when mechanised processes were introduced in the 1860s that New Zealand’s flax industry started to really grow. By 1918 flax fibre exports made up approximately five per cent of New Zealand’s exports. New Zealand did not produce hemp on the scale or to the quality of places such as Philippines and East Africa, but had several boom periods when demand outweighed supply from those places.

Flaxmills began to be established in the wider Manawatu/Horowhenua region in the late 1860s, coinciding with early earnest European settlement. Described as being a ‘major source of wealth,’ the regional flaxmilling industry produced fibre for items such as course textiles and rope, which was particularly important for shipping. While the regional industry had several boom periods between the 1860s and the turn of the twentieth century it was not until the early twentieth century that the Makerua Swamp’s local industry matured. In 1886 the completion of the Wellington-Manawatu Railway to Longburn, which went around the swamp, boosted the Manawatu/Horowhenua industry because it increased access and export opportunities. In the 1890s William Akers progressively purchased and leased land from local Maori in the Makerua Swamp at Opiki. However, most of the mills in the swamp were only established around the turn of the twentieth century. In 1902 the Makerua Estate Company Limited was formed, which included high profile Wellington businessman John Plimmer (1812-1905) and experienced flaxmiller Alfred Seifert (1877-1945), who purchased 12,343 acres of swampland. Raupo was cleared from the area and drainage systems implemented to promote flax growth, and then the company began subdividing and selling off its holdings.

Demand for flax products was high during World War One and the Makerua Swamp had developed into the largest commercial flax swamp in New Zealand by then. The swamp’s peak production was between 1910 and 1918, and there were many companies who were milling flax from the swamp at this time, including the Seifert family. Their seven-stripper Miranui mill was thought to be the largest in the Southern Hemisphere. Even so, the Tane Hemp Company Limited’s four-stripper flaxmill at Opiki (then known as Rangitane), constructed in 1915, was one of New Zealand’s largest. This company was established by a group of shareholder directors, including Managing Director Herman Seifert (1866-1948), Hugh Akers (1877-1932), along with his brother Arthur (1888-1944) and uncle Edwin (1852-1934). Demand for the hemp was reflected through the building of public and private roads through the swamp during this period, creating greater access for people and goods.

Production was soon progressing well, with the green flax being supplied by the Akers brothers, and processed at the Tane mill and the neighbouring Rangitane mill, which the Tane Hemp Company Limited also owned. Resultantly, the company determined to build a bridge over the Manawatu River to provide a direct transport link to the Rangiotu railway station. Previously people and goods were transported across the Manawatu River using platforms and cages attached to wires, or punts, which were impractical given the quantities of product generated by the mills. The other option was inefficient and involved using tramways and roads to take product to Linton’s railway station. Therefore, a suspension bridge was constructed for the company between March 1917 and January 1918. This was primarily beneficial to the Tane Hemp Company, but also useful for the Akers brothers’ and Louis Seifert’s other operations. As such these parties contributed to its construction cost of £2821. The group also formed an agreement which detailed access rights and the division of maintenance costs.

Designed and built by well-known Pahiatua bridge-builder Joseph Dawson (1843-1923), the bridge’s 145.4 metre timber deck span was suspended from wire rope catenaries stretching over and between high concrete towers. Dawson was born in Tasmania, coming to Christchurch at age 26 where he was engaged as a carpenter apprentice. After gaining experience erecting railway bridges he moved to the Wairarapa, living in several places before finally settling in Pahiatua in 1889. Here he farmed, but also designed and built bridges. Dawson earned a reputation for ‘the economy and very sound construction of his work, as well as speed of erection.’ He specialised in suspension bridges, patenting his ‘Dawson system,’ and constructing about 15 structures by the time his Opiki bridge was completed.

Dawson appears to have been self-taught success in the engineering field. At this time the newly formed New Zealand Society of Civil Engineers was advocating for greater regulation of engineers and the resulting Engineers Registration Act (1924) signalled the end for talented amateurs and self-taught bridge builders, like Dawson, being able to complete large scale works such as the Tane Hemp Company Suspension Bridge. Unfortunately, it seems that all of his road bridges have been demolished, with the only remnants being those of his Opiki bridge, as well as the towers of a smaller 1914 structure across the Rangitikei River.

It is highly likely that the team constructing the suspension bridge at Opiki, supervised by foreman Nathaniel Malcolm, were mostly hands from the Tane mill. This seems particularly probable especially during the winter months of 1917, as this was always an off-season for flax milling, being too wet to harvest the flax. Evidence of other cost savings and efficiencies were the suspension rods being fabricated by the mill’s blacksmith, Ernest Henderson, and the suspension cables being recycled from gold-mining operations in Waihi. The company’s suspension bridge was newsworthy because it had the longest main span of any bridge in New Zealand when it was built.

The company must have intended to be operating its mill for quite some time in order to make their impressive suspension bridge fiscally viable. However, the Tane Hemp Company Limited, and the majority of its immediate neighbours, closed their flaxmills between 1921 and 1922. This was the result of a post-war slump in the market, and because much of the flax became infected by a virulent yellow leaf disease which seems to have started making its way through the Makerua Swamp by early 1918. At this time it was estimated that 1500 acres of the property that the company leased from Hugh Akers (1877-1932) were affected. Akers predicted that ‘unless the disease is grappled with and beaten it will seriously affect the future of the industry.’ However, in addition to the recently completed bridge the company had also upgraded their mill facilities. Its new concrete chimney, the smokestack for the steam engine that powered the mill, replaced the mill’s original metal one. The mill was said to be unique in New Zealand because of its concrete chimney.

By 1920 the situation for the local flax industry was getting progressively worse and the major landowner flaxmillers in the Makerua Swamp - Akers, John Liggins, and Alfred and Herman Seifert - began considering subdividing and draining the land for farming. At this time they even approached the County Council seeking funding help to build a road through their land which would provide a more direct, less winding route from Shannon to Palmerston North. The County Council was also offered, but did not accept, the suspension bridge for £3,000.

Within two years the Tane Hemp Company Limited’s mill had closed and the building was demolished, with the exception of its tall concrete chimney. By 1934 the region’s formerly lucrative flax industry had dwindled to only four operative mills, all of them in the Foxton area.

When the Tane flaxmill closed the principal local landowner, and former Tane Hemp Company Limited shareholder, Hugh Akers, took over the mill’s former site, including the bridge. It then seems that the Makerua Drainage Board, of which Akers was a member, began draining the swampland with financial support from the County Council. In 1925 the drainage scheme was nearly complete and it was reported that:

‘A few years ago [Mr Hugh Akers property] was heavy flax; then it was hit hard by ‘yellow leaf’; to-day it is one of the most beautiful tracts of grassland one could see anywhere on earth.’

When the newly drained land was subdivided Akers received more and more requests from people wanting to use his private bridge. In order to maintain the bridge a toll was charged to users, with the exception of emergency vehicles and visitors of the Akers family. A bridge-keeper’s house was constructed at the west end of the bridge in 1925, in preparation for the start of toll-charging in February 1926.

The Akers family, through Hugh’s father William, had been involved in flaxmilling near Tokomaru since the early twentieth century, but the family had owned land in the Manawatu since the 1870s. William even went on a world tour in 1910 to make ‘a special study of all of the rivals of New Zealand hemp, especially Manila.’ By the 1890s, when William began leasing and buying land at Opiki, Hugh had his own sheep run near Ashhurst. Upon his death in 1932, it was said that there ‘was no better known figure in the district than the late Mr Hugh Akers, who has been associated with the progress of the Manawatu for the past forty years.’

By the 1930s the deviation road through the former Makerua Swamp had been constructed and by 1934 was being considered for highway designation. The Automobile Association campaigned for this change, and in 1937 the Minister for Public Works, Robert Semple (1873-1955), agreed to the proposal. Apparently the suspension bridge had not been maintained to a level which satisfied the Public Works Department, who planned to replace it. There was also public lobbying for the toll to be removed as soon as the highway was established. On one occasion in 1938 Semple himself encountered the frustration of having to pay the toll. He was reportedly indignant about it, but the toll-keeper stood firm. Infuriated, Semple is reported to have shouted: ‘This antique structure from a comic opera must go! We will build a new one immediately – we will not have toll bridges in this country.’ Semple did not live to see his plan realised. For another three decades the bridge remained notable as being the only privately owned toll highway bridge in New Zealand.

Meanwhile, the chimney, not used for several decades, temporarily gained a new lease on life. During World War Two the structure was used by the Opiki Home Guard’s Signal Division to relay smoke messages from as far away as Shannon. However, after the war the chimney went back to being a static monument to the local flaxmill industry.

It was said that Opiki became well-known for its bridge, the structure being a local landmark, with Palmerston North pleasure drivers often specifically bringing visitors out to see it. This was a novelty, but could also be an adrenalin rush on windy days when the deck swayed around ‘with gay abandon.’ By the 1960s traffic using the bridge had increased to the point where it made sense to introduce toll concession tickets.

As well as the demands placed on the structure by the motoring public, there was another reason why plans to replace the bridge began in earnest in the early 1960s. At this time the local Catchment Board was building stopbanks along the northern side of the Manawatu River. While this flood protection was good for the surrounding farms, engineers showed that a moderate flood would submerge the bridge, potentially causing its failure. Then in 1965 the National Roads Board agreed to subsidise the construction of a new two-lane concrete bridge. The suspension bridge remained in use, with tolls in place, until 1969 when the Horowhenua County Council opened its new bridge nearby, which did not have an associated toll or a three ton weight-limit like the old structure.

It was soon after the opening of the new bridge that the deck of the suspension bridge was removed in 1970 as a public safety measure and to forestall vandalism, as well as a flood-damage prevention measure in case the heavy beams dislodged. However, the towers and flaxmill chimney were not thought problematic, so Alan Akers (son of Hugh) retained these elements. Like the flaxmill, the fabric from the bridge was recycled in buildings and structures on the Akers’ farms. The Manawatu Catchment Board also advocated for the removal of the bridge-keeper’s house because it interrupted their flood control scheme.

The New Zealand Historic Places Trust (NZHPT) first recognised the significance of the structures in late 1970s. More recently, in 2003 the NZHPT Manawatu Branch Committee installed a cairn and plaque next to the main highway which describes local flaxmilling history and the Tane Hemp Company Limited’s remnant structures’ place in it. At the time this was further elaborated upon in Molly Akers’ book Suspended Access: the history of the privately owned Opiki toll bridge, which the Manawatu Branch Committee published.

Physical Description

Current Description

Located between Shannon and Palmerston North, Opiki is a rural area characterised by its relatively flat pastureland which the Manawatu River snakes through. Flood control works in the vicinity of the Tane Hemp Company Limited Suspension Bridge and Flaxmill Remains include a 1960s masonry weir along the western bank of the river, built in the same period as the current highway bridge. The visible structures could potentially be complemented by subsurface foundations and other remnants of the flaxmill and associated flax growing activities.

The former flaxmill chimney and the neighbouring suspension bridge towers form a strong vertical point of interest in the landscape for those travelling along State Highway 56. Formerly closely connected with the main road, the current highway circumvents the structures, crossing the Manawatu River further south. The route of the old road can still be discerned, cutting through the flood plain, particularly on the east side of the river.

Former Palmerston North City Archivist, Ian Matheson, had a particular research interest in the region’s flaxmilling industry. He noted that the Tane Hemp Company Limited mill and bridge remains ‘provide one of the most substantive and distinctive links with the early flaxmilling activities of the Manawatu and N.Z.’ Matheson also stated that ‘other flaxmill sites are marked by concrete blocks or wooden or corrugated iron buildings, but [in comparison with the Opiki structures] these remains are usually insubstantial and undistinguished in appearance.’ A recent New Zealand Historic Places Trust Manawatu Branch Committee report corroborates Matheson’s view.

Comparisons

Nationally, some examples of built heritage relating to the flax industry include Marlborough’s Marshland Flaxmill and Vercoes Flax Mill Ruins, and Southland’s Templeton Flax Mill Complex. With the exception of the former Vercoes mill, these sites are reasonably complete examples of a late nineteenth and early twentieth century flaxmills in New Zealand. Similar to the Opiki chimney, the Vercoes remains are the result of the mill’s demolition in the 1920s. Unlike these late nineteenth century examples the Tane Hemp Company Limited’s operation seems to have been on a grander scale and was located in what is regarded as New Zealand’s most important flax production region. Although the buildings are no longer extant, the materials used and scale of the remnant structures suggests the comprehensive, industrial nature of the activities they originally served.

The former flaxmill site at Opiki is unique in New Zealand because it includes the impressive suspension bridge, which was important to the local industry but continued to have a life after the mills closed. The vestiges of the bridge are comparable to the Alexandra Bridge Piers in Central Otago, Category 1 historic place (Register no. 349). This structure, dating from 1880, also had its deck taken away in the twentieth century after it was replaced in the highway system, but in its case the catenaries were also removed. Like the Opiki structure it was also a suspension bridge, whose remaining towers are a significant local landmark, and a lasting tribute to its engineer.

Suspension bridge remains

The suspension bridge remnants have been described by engineering historian Geoffrey Thornton as ‘a forlorn engineering sculpture.’ Even when newly completed it was said that the structure’s ‘fine towers, rising like stately monuments above the monotonous scenery of the huge swamp, give quite a new and picturesque feature to the locality.’

The towers stand 145.4 m apart on either side of the Manawatu River. When completed in 1918 the Tane Hemp Company Limited’s bridge was ‘the longest suspension bridge that has been constructed in New Zealand, and probably the biggest bridge of its kind in Australasia.’ Despite the deck having been removed, the presence of the catenaries provides a sense of the grand former span of the bridge by linking and filling the space between the two towers.

According to statistics in Thornton’s survey of New Zealand bridges, the Opiki bridge had the second longest main span of any of pre-1940 road bridge, behind the 151 metres of the Mata River Suspension Bridge (1931). This structure was near Ruatoria but has been demolished. The Arapuni Power Station Suspension Bridge (1926) is 152.4 metres in length, but it was designed as a pedestrian structure. The towers of these structures were braced steel. Before the Opiki bridge was built the Clifden Suspension Bridge had the longest main span in New Zealand, at 111.5 metres, with its approximately 7.5 metre concrete towers being much shorter than the Tane Hemp Company bridge’s.

Indeed, it was not until the mid-twentieth century that lengthier spans became more feasible for road bridges. Developments in materials and engineering knowledge throughout the twentieth century led to impressive spans, such as the 243.8 metre long central section of Auckland’s steel Harbour Bridge. However, even now the longest span in a railway bridge in New Zealand is 110 metres. Therefore, the remnants of the Tane Hemp Company’s bridge are a monument to one of the longest main span road bridges ever constructed in New Zealand.

Each of the pair of reinforced concrete towers is 14.6 metres tall, standing on concrete abutments that are said to be about 3 metres deep. In suspension bridges the height of the towers reflects the span lengths that can be achieved. The Opiki bridge’s substantial towers meant the suspension cables needed to be longer to fit over top, and therein the forces on the structure incurred by a longer span were adequately compensated for. The towers demonstrate the quickly gained confidence in reinforced concrete by New Zealand bridge builders in the early decades of the twentieth century. New Zealand’s first reinforced concrete bridge was Dunedin’s small George Street Bridge (1903), but within a few years structures like the Grafton Bridge (1910) and the Opiki suspension bridge had been created.

The tower posts are evenly spaced, tapering towards the top. The pairs of posts are linked by three horizontal braces with a shallow arch shaped lower edge. The towers are austere with the exception of the raised wedge detailing, stemming from the posts but stopping short of a central touching point. This decoration is on both sides of the bracing. Considering that the bridge remnants are not actively maintained the concrete seems to be in reasonably good condition aside from some chipping on the corners.

Photographic evidence suggests that originally the concrete may have been plastered. This would have been a cosmetic measure, hiding the boxing indentations created when the concrete was poured. While the plaster has now largely worn off, some of the bridge’s mid twentieth century painted signage is still present. This information can still be made out at on the lower section of both the eastern tower’s posts. The signs notified the toll bridge users of load and speed restrictions and the toll prices, but are now only legible on close inspection. A speed limit notice is also present on the western tower’s north post.

The 16 wire ropes which made up the suspension cables were apparently recycled from the winding ropes at a Waihi goldmine. These century-old wires are carried over the towers and many are still anchored in concrete several metres behind. In the 52 years that the bridge was used for traffic, only one cable broke, but it was speedily repaired. Because they no longer have a functional purpose the cables have been allowed to degrade. Some tethered cables are no longer under tension. Others hang free from the anchors, while some now lie in the grass around the towers. With the deck having been removed, the vertical hangers, fabricated by Henderson, swing freely from the catenaries.

Flaxmill remains

The chimney and the bridge remains were retained by the Akers family specifically as a reminder of the Manawatu and Horowhenua’s once important flaxmilling industry. The visible remains of the flaxmill processing facilities include the chimney and rectangular blocks of concrete, immediately north of the chimney, which the mill’s engine had been bolted to. The chimney is taller than the neighbouring suspension bridge towers, which suggest it is over 20 metres high. Rising from a square base, the chimney’s column is broader in the lower section. The base and lower chimney each have rectangular cavities on their northwest sides, where it appears that the discharged smoke from the steam engine entered the chimney structure.

Construction Dates

Original Construction
1916 -
Flaxmill constructed.

Additional building added to site
1917 - 1918
Suspension Bridge construction begins in March 1917 and is completed January 1918.

Additional building added to site
1918 -
Chimney constructed.

Demolished - additional building on site
1922 -
Mill facility demolished with the exception of its chimney.

Modification
1970 -
Bridge decking removed and bridge-keepers house demolished.

Construction Details

Concrete, steel.

Public NZAA Number

S24/48

Completion Date

7th October 2013

Report Written By

Karen Astwood

Information Sources

Buick, 1903 (1975)

TL Buick, 'Old Manawatu', Christchurch, 1903 (1975)

Evening Post

Evening Post

4 January 1915, 5 November 1925, 22 September 1932, 22 November 1934, 2 February 1937, 26 April 1939

Law, 1987

Marjorie D. Law, From bush & swamp: the centenary of Shannon, 1887-1897, Palmerston North, 1987

Marlborough Express

Marlborough Express

31 October 1906

Thornton, 2001

Geoffrey Thornton, Bridging the Gap, Early Bridges in New Zealand 1830-1939, Auckland, 2001

Thornton, 1982

Geoffrey G. Thornton, New Zealand's Industrial Heritage, A.H. & A.W. Reed, Wellington, 1982

Adkin, G Leslie, 1948

Horowhenua: its Maori place-names and their topographical and historical background Department of Internal Affairs p332

Wairarapa Daily Times

Wairarapa Daily Times

11 April 1918

Manawatu Standard

Manawatu Standard

25 February 1909, 8 April 1910

Horowhenua Chronicle

Horowhenua Chronicle

16 February 1918, 13 December 1920

Akers, 2003

M. J. Akers, Suspended Access: The history of the privately owned Opiki toll bridge, 1918-1969, Palmerston North, M.J. Akers and New Zealand Historic Places Trust, Manawatu Branch, 2003

Other Information

A fully referenced registration report is available from the Central Region Office of the NZHPT.

Please note that entry on the New Zealand Heritage List/Rarangi Korero identifies only the heritage values of the property concerned, and should not be construed as advice on the state of the property, or as a comment of its soundness or safety, including in regard to earthquake risk, safety in the event of fire, or insanitary conditions.