Don't laugh at those big semi side mirrors !
I did a delivery a few years ago and there was zero visiblity of the back of the boat when backing into a slip due to "additions" done.(he added a tiki bar behind the fly bridge and had disconnected the lower station).
The owner had installed those mirrors (he did have enought sense not to make them permanent but did put them in when getting ready to dock) and they worked.
Besides, with the way the rest of the boat looked, the mirrors fit right in !!!