When diving to depths greater than 10 meters, dive time is limited. At 26 meters on the Kronan site, the effective diving time is about 50 minutes daily for each diver when breathing compressed air. This is because the diving is non-stop diving i.e. divers can make a direct ascent to the surface. Currents on the site are normally weak, but temperatures seldom exceed +5 degrees centigrade; because of this safety dictates that divers use only drysuits.
The limited time for diving demands careful planning for the work on the bottom as well as on the surface. Since the diving is not an end in itself, but a way of 'getting to work' the underwater archaeological work must have the highest priority. This puts specific demands on the divers skill and security measures employed. Each diving team on the Kronan consists of 20-25 divers. Divers all dive in buddy-pairs with a line connecting both together for safety. Also, all maintenance work is carried out on site, in order to facilitate the archaeological operations.