We don't do either currently, but would have tanks and would be able to feed directly. As I said these are questions we want clarification on.
Sorry if they're obviously odd or wrong, appreciate your help.
I understand your concept of the pipes freezing... which would be a concern in the winter, but I thought that this could be something which is addressed in the winter, we have another boat and the pipes from the yard have never frozen just the pipes running from the tap which can be replaced with another pipe if necessary therefore the option to fill up or have a 'water supply' is always possible.
With the right stop cocks and taps I thought life would be easier is to have a constant feed of mains water to the boat?