I can find a 32 feet yacht for 850 euro and at the same time a 37 feet for the same period for 1800 euro. Why is that?
Newer yachts are always more expensive that older ones. Usually the charter price of a yacht is lowered after the 5 th year, and is even lowered after the 8 th year.
Some brands like Beneteau and Jeanneau are chartered more expensive that for example Bavaria yachts as it is more expensive to buy them, over a similar size and number of cabin Bavaria, but this is not the rule. There are exceptions depending on the models.