miessaari and the small pyöräsaari formed the western reach of the naval front main line of defence. they are located near the coast of espoo, and protected the coastal routes on the western flank of the fortress. miessaari naval front battery number 40 had four canet guns, while pyöräsaari had two two-gun batteries of light 57 mm guns. pyöräsaari was connected to miessaari by a bridge in 1917. the construction of the canet gun battery began in spring 1915, the guns were installed in may 1916 and the construction was mostly finished by early 1917, though some work on the interior shelters continued until summer 1917. pyöräsaari 57 mm gun positions were quarried in late autumn 1915 and completed in june 1916. the islands also formed the seam between naval and land fronts, and miessaari had also a land-facing battery number 115 of six 190 pood model 1877 siege guns, supporting the base xxxiv in haukilahti-westend area.