Not sure weather somewhere apart from the north of Germany beach chairs are hirable. In this area
beach chairs are not ordinary chairs which are put in the sand, coast sitting is different over there:
There is only space for two persons sitting next to each other but the good side is that it is protecting its user from wind and coldness.
One beach chairs about 10 Euro. Usually they are sold in little shops nearby the beach.
They are very common; usually people like to sit inside the whole day (if not walking along the beach). Swimming is only a few hours a day possible since the low tide is very low on German coasts
You can see on the picture above how far the water can leave and how near the big ships are… but don’t be fooled; the tide is everyday much smaller. It is possible (but very risky if you are not familiar with flood times) to walk miles until you see the water again. There are even guides from Cuxhafen to a German islands which can be done by feet at low tide.