I am new to all of this but I tried to find it on my scope few days ago and no luck. I guess I have to learn star hopping little more to find it. For example, I spotted Ring nebula fairly quickly, but this one got away from me... for now. I used 38mm (2") and 25 EPs.
Edit: I think I just realized that I was actually looking to find M101, not M51. Both are in Ursa Major.