Just wanted to say that Star Ferry in Hong Kong is wheelchair accessible.
After buying your ticket, there is a special gate you can go through and staff will guide you to the boat. You get on at the lower level, so you must go down a slope. Unfortunately, it is a bumpy ride as there are bumps to prevent slipping. The slope gets steeper at the end, so you might want to go backwards in your wheelchair.
To get on the boat, passengers go up a steel panel that is lowered from the boat (it is pretty wide). There is still a step up to it so staff put down a portable ramp to drive up. If the water is a bit rough the ramp moves around so it can be a bit scary!
Once in the boat there is a space for wheelchair users. Unfortunately the steel loading panel is right in front of the wheelchair seet so you cannot really see much! If you move to another area you can see over the side.