Not only the environment was rebuilt, the gates of the lock gad to be replaced in 1820, the whole construction was subject for a comprehensive repair in 1836 and closed for three months autumn 1839. Half a dozen metal pump stocks in diameter were found in the embankment but not understood as such, the entire machinery therefore thrown out of gear, while skippers exceeding the permissible draught attempted to pull their ships over the sill. The Blue bridge was repaired and en new pivoted bridge built by the red one. Finally in 1831, Lieutenant colonel Gustaf Adolf Lagerheim (1788–1845), who had worked at the Göta Canal, was commissioned to investigate a new bridge and eventually became the first person to propose a new seaway south of Södermalm, a suggestion however reject as to expensive, why he instead made a proposal for a new lock before he fell out with the building authorities and left the capital. Successive plans for a new bridge were first encouraged as His Majesty personally granted subsidies worth 20,000 riksdaler annually during a period of ten years starting from 1837, provided that the city allocated the same amount to cover the cost was estimated to 394,000 riksdaler, the plans then fell upon problems however, as a competition in 1841 awarding the winning proposal 200 ducats produced no entries, and a new competition in 1843 awarding 500 ducats resulted in the same outcome. The savior appeared in 1845 when lieutenant colonel Nils Ericson (1802–1870), who had worked for Baltzar von Platen at Göta Canal, delivered a proposal for which was, except for the award, also given 2,000 riksdaler for a supplemental investigation. The new lock required to be 9,5 meters wide, 3,6 meters deep at low tide, while the distance between the gates should be made 45 meters. The cost was estimated to 422,000 riksdaler, and Ericson's recompense settled at 40,000 riksdaler to be paid once the sluice was completed.