There are some storage space at Mellsten Beach (7 containers), and at Lauttasaari (3 containers) for boards and unrigged sails. However, thay are all quite full and it is not straightforward to get a slot.
) is the main Slalom and Formula venue in the area, while there mostly are smaller boards at Lauttasaari (http://maps.google.com/maps?f=q&hl=e...9,0.02914&z=15
Convenience, especially for after work sessions of course depends where in the region you live.
Contact me at pg at konafinland dot com and I will try to help you out.