These two mobile office buildings for the water police in the North of the Netherlands were built in a shipyard of Spuyt arkenbouw in Heerenveen. The bottom is made of concrete, and the upper construction of wood. Both ‘werk-arken’ were brought over water to their current dry land locations. Should the organization need to move, the entire building could be hoisted back into the water by the help of a crane and be transported by river to the new location.