Calendaring for boat share
Ownership of many boats is syndicated and there are dedicated syndicate management platforms to administer time allocation and cost allocation. But, if the you are going to add a calendaring function for maintenance scheduling you should consider including some basic functionality to allocate time-share. I suggest flexibility for each user in the syndicate to have a certain number of points and to allow the syndicate to set different days with different points values e.g. weekends, public holidays, school holidays etc.