Säck is lagune almost inside the island Krokholmen, which makes it protected from all wind direction. It's a very popular natural habour and on a beautiful summer day you can easily find 30 boats inside the lagune. The cliffs on the left side of the lagunes is quit high and I would definitly recommend to take the walk up and enjoy the view and the 'sunset', as much as it sets int he summer time.
Tips about Säck:
the inlet is quit shallow, approx 2-3 m, so stay in the middle of the channel.
you can find two skärgårdmaja's (primitiv toilets) and garbage disposal on the island, one on the right side on the entrance to the lagune and one at the bottom of the lagune.