I'm slowly learning to use the DSLR I bought a few years back (Canon XS). I've signed up and am on my 2nd week of a beginners camera class at the adult school program and have also signed up and have started watching the beginners videos on Lynda.com.
That said we are hosting boat races at my day job tomorrow and I wanted to snap some nice pictures. I only have the stock lens (18-55).

Should I just keep it on sport mode or should I set my own f and  and ISO? It's still very confusing for me and I'm worried I'll take some crummy, blurry pics.
We are supposed to close to 100 degrees tomorrow and sunny and I'll prob be 50-60 yards from where the boats will criss the finish line.

Should I keep the f/ at the highest setting, (4.5 I believe us the highest setting) and the ISO on auto?
I just bought a new sd card, a Sandisk 32g Extreme Plus card so I think that should be enough for storage.

I appreciate any tips. Thanks guys.

Assuming it is going to be sunny out (which it sounds like it is), I would set the ISO to 400 and live in aperture priority (AV) at your widest setting to stop motion.

With the stock lens, I'd be more concerned about AF on fast moving objects. If you are getting fast enough shutter speeds, stop down to f/8 or 11 to help with depth of field and give the lens more wiggle room on missed focus.

The widest setting being the lowest number correct (f/4.5)?

Correct.  You can use sport mode if you want-personally I avoid the Creative Zone modes like the plague.

Ok. Thanks for the tips.

@OP: use "AI-Servo" mode for autofocus.