The German service barge "Carl Straat" is similar in concept, but the bell is lowered by swinging the access tube. "Carl Straat" was built in 1963 for the Waterways and Shipping Directorate West in Münster. The 6 m × 4 m × 2.5 m bell is accessible through a 2 m diameter tube and an airlock. A pantograph system keeps the bell and internal stairs level at all depths. Maximum working depth is 10 m. The vessel is used on those inland waterways which have locks large enough to accommodate its 52 m length overall, 11.8 m beam and 1.6 m draft.