High tide or low tide

E|+-------------------------------------------------------------| 
B|+--13-13-13-13--------------------------------6--5------------| 
G|+--------------14----------12-----------7---7----------9/10---| 
D|+-----------------15----------14----------7---------7---------| 
A|+--------------------15----------15---------------------------| 
E|+-----------------------------------15------------------------| 

+---------------------------------------5-----------------------------|
+-6-----6-----6-----6------5-----5-------5----6----6--------6-5-3/1|--|
+---7-----7-----7-----7------6-----6-------6/---7----7----------------|
+-----8-----8-----8-----8\-----7-----7------------8----8----8-7-5/3|--|
+---------------------------------------------------------------------|
+---------------------------------------------------------------------|