Sacrificial Zincs

My trailer has never been in salt either,much easier to have it lifted in and out. Just make
sure your lift rings and their attachments are in good shape. It is my understanding that
zincs are needed if you moor in an area that has stray electrical currents from other items
in the water. I don't have them as I never leave it in. You'll want one on the shaft and rudder.
Matter of fact you can see the hole in my rudder for one in this picture-

So when I first bought my boat it was used almost exclusively in salt water but very rarely overnight. Since my trailer build and engine rebuild it hasn't touched the salt. Unfortunately this results in much less use for the boat. However, I am in the process of joining a local yacht club which will allow me to use a hoist to put the boat in the water without getting the new trailer salty. I am currently thinking that I would like to do this and am contemplating towing the Tique over to catalina island for a couple of trips behind my grandparents Grand Banks 32 that I have access to. I currently do not have any zincs on the boat and feel like it probably should be something that I add if planning on leaving the boat in the salt water any longer than a day or two. What say you? Add one to the prop shaft? WIll it effect performance etc?