Marinas may also begin preparations for the recreational boating season by servicing boats and other watercraft and placing boats in the water, but not open to the public. Boats and watercraft must be secured to a dock in the marina until public access is allowed.

Source: https://news.ontario.ca/opo/en/2020/05/certain-businesses-allowed-to-reopen-under-strict-safety-guidelines.html 

Health and Safety Guidance for Marinas: https://www.wsps.ca/WSPS/media/Site/Resources/Downloads/covid-19-marinas-health-and-safety-guidance.pdf?ext=.pdf