If you should decide that you would like to search for agates on the lower reaches of the beaches of Usan, then one aspect of the tides there will quickly become apparent. If the tide is scheduled to be lowest at say, 08:43am for instance, then you will have under one hour to investigate the deepest areas of seabed uncovered at this time. After that, the tide will begin to surge towards the shore once again. The extant of swell prevalent at the time will also have considerable influence on the time you have, and in stormier seas the tide will seemingly not retreat to the same extent as during times when the North Sea is calm and not raging further from land. Of course, medial areas will be uncovered for longer periods regardless, however, beginning during the spring and increasingly during summer to a peak around August, the seaweed on these lower portions of shoreline will be at its most verdant and bountiful, and this obviously makes searching areas of shingle potentially dangerous and difficult. Only close familiarity with the area can help in such instances, and after, or indeed during periods of rough weather, persistance, as usual, can pay-off.