In connection with installation of district heating mains from Vendsyssel District Heating Plant to Aalborg District Heating Plant, Aarsleff performed a crossing of the Liim Fiord with two district heating mains.

Aarsleff performed the sea crossing by pulling pipelines at the bottom of an excavated pipe trench. The pipe trench was, at water depths below 1 m, excavated from shore and at depths exceeding 1 m, excavations were executed from a dredger placed on a jack-up platform controlled by satellite equipment.

The pipes were welded and pressure tested on shore. The two district heating mains were then pulled through the casing pipes by means of a specially developed method enabling the pulling to take place without wear and tear on the vulnerable HDPE jacket pipe.

On the opposite side of the Liim Fiord a winch was set up. From here a wire was placed in the excavated pipe trench by boat and controlled by divers. The wire was finally attached to the pipeline and the pulling was performed by using the bottom-pulling method.