shower
I did this with my last Irwin. I put the shower on the stern deck. What I did was to tie the plumbing in on the right side inside the locker at the stern and the shower head came thru the stern vent.
The wash down for the bow I installed a deck hose fitting at the bow just behind the sprite, The supply hose ran in the bulge to the pump that was mounted next the the pump for the fresh water.