Water will likely not come in bryan. You just need a coating on the whole shaft. I put a few drops of 3in1 on the back near the prop where the brass bushing is. Here's a good excercise for a new SV owner. Take the moter out and clean the shaft off. Put it in, and turn it. Now pull it out and put a real thick coat of grease on it. Re-insert and turn it again by hand. Now remove it and using your hand wipe off most of what's there. repeat. Then if you like try the 3in1. I pull my shaft after I'm done at the lake and wipe it clean and put it inside the hull. I think that lets eveything dry out best.

That's all I got. Good luck.