I noticed that planimeters come with a piece of information related to (something like) "area of neutral circle"...
I am just starting in boat design and I bought a planimeter from an e-bay auction. It seems it is in very good condition. I am not sure, however, if the information above is critical or if I can somehow "calibrate" the instrument before using it.
Any advise is welcome.... I hope the question make sense for some of you. Keep in mind that I am not very knowledgeble in these matters...