I have more to add when I find the pictures.
This one is resin coated before painting so yes it could be used directly into the water if there was wheeled access.
It is the frame/stand that I made to build the model on, I just added axles and wheels.
Bear in mind this is at least a 34kg Tug in sailing order.
Another cart added that also started as a build stand.
This one also carries the Shannon.
The handle is shared between both carts and attached with an R clip