There seems to be some confusion about the role of HSE and health and safety law. HSE and local authorities enforce health and safety (H&S) law, they don't make it. H&S law is made by parliament and the Health and Safety at Work etc. Act 1974 places a duty on employers to ensure, so far as reasonably practicable, the health and safety of their employees and those likely to be affected by their work. Thus, a marina is responsible for the health and safety of its employees and those using the employer's premises. i.e the marina. (That's a bit of a generalisation, and it is couched in terms of what is reasonably practicable, but you get the gist). (See also, Marina development safety | Canal & River Trust (canalrivertrust.org.uk) )
I hope that helps.
James (a retired HSE Principal Inspector)