Mini Archipelagos - the book supports and complements the Great Route Book of the Turku Scout-Sissi Harbor Book series, but also works as such for those for whom the route book is already unknown. The book contains 80 special maps and 20 detailed maps of the Archipelago Sea and the western Gulf of Finland. There are sites in the area where the main depth data from the nautical chart are outside the 10-meter depth curve or are completely missing. Indicative depth curves for shallow (less than about 3 m) and shallow (less than 4 - 6 m) water areas have been drawn on special maps using aerial photographs. With the help of these maps, it is also possible to use boats safely in maze-like and rugged archipelago areas where depth measurements are incomplete. Of course, this information is not complete either, despite its efforts. The passage depth of the boat routes marked on the maps has not been given. They are mainly intended for use on a sailboat with a draft of 2.35 m, unless a lower