Chain boat navigation on the Neckar

On 23 May 1878, a richly-flagged towboat, the Kettenschiff No. I, was waiting at Wimpfen with a train of empty Neckar barges for the probably more than 500 invited guests. Among the guests were Minister of State von Sick and other high-ranking officials and members of parliament from neighbouring states. The next day the steamboat travelled to Mannheim. From there she set off on her first real tow with nine barges attached (total load 360 tonnes) and reached Heilbronn on 27 May. The journey took about half the time of the horse-drawn train. At the same time, the costs were significantly reduced. Shipping became competitive again. On 15 June 1878, King Charles I inspected the equipment and travelled with it from Neckarsulm to Heilbronn. A new chain steamer was put into service in the following months by September. In 1880, the fifth chain steamer was added.

Skippers were quick to embrace the new chain towing service. Between 1878 and 1883, the number of vessels towed and cargo transported increased steadily. By the mid-1880s, upriver traffic on the Neckar had roughly doubled compared to the mid-1870s, despite the opening of the new Neckargemünd-Eberbach-Neckarelz-Jagstfeld (1879) and Jagstfeld-Heilbronn (1882) railway lines, which ran parallel to the river. As the company's income increased, the returns paid to shareholders were between 5.5% and 6.6%. In 1884 there was a slight downturn in shipping. Due to a prolonged, extreme drought, water levels were very low throughout the year, reaching a low of only 45 cm on two occasions. Not only the low rainfall, but also the diversion of water by farmers and the damming up of waterworks at night meant that the tugs had to interrupt their voyages repeatedly due to lack of water. As far as possible, coal and hawsers from the chain steamers were transferred to tenders to reduce the draught. This meant that shipping operations could be maintained down to a minimum water depth of 50 cm.

At all times, the tug company ensured that its prices were competitive with those of the railway, while maintaining its own profitability, so that boatmen could offer their services at competitive prices and still make a reasonable living. For example, it gave discounts to boatmen when water levels were low. The state of Württemberg itself had a vested interest in promoting trade on the Neckar. The income from the trade in Heilbronn, as well as the income from the towing service, went directly to the state of Württemberg. As a result, shipping was favoured at the same cost and the Württemberg State Railway was instructed to transport its coal to Heilbronn by ship. Three steam cranes were specially built by the Heilbronn tugboat company to unload the ships.

After one chamber of the Wilhelm Canal lock, built in 1821, had been enlarged to 48 metres long and 7 metres wide in 1884 to allow the passage of a chain steamer, chain navigation was extended to 12 kilometres upstream of Heilbronn at the suggestion of the supervisory board of the Lauffen cement works. From a technical point of view, the conditions for this additional stretch were simpler than those for individual sections of the river already used for chain navigation. Financially, the company hoped to generate additional income from the prospect of transporting limestone, coal and coke not only on the new route but also on existing sections. In contrast, the investment costs for operating resources were very low. The required length of chain was already in stock. Wear of the chain links at their contact surfaces resulted in elongation of the chain, which was small per link but significant over the total length of the chain. As a result, sections of chain were repeatedly cut out and stored over the years. In addition, the chain was subjected to increased stress and wear in river sections with very strong currents and tight bends. At the same time, a chain break in these sections would have much greater consequences, so the chain had to be replaced earlier. However, these sections of chain could still be used for the new line with a reduced number of towed vessels. The extension of the line to Lauffen therefore paid for itself without a new government guarantee and was completed in 1890 after the concession was extended.