I should have said "surface temp" in my last post.

John S.

John I agree the speed is alway way off on my finder compared to the GPS speed reading.I do use the temp reading for the spring time.I have a cannon temp probe for the summer as far as down speed and temp is concerned and is right on the $ with my GPS speed.

Erin

I did the same thing as John S -- i did not install the speed wheel with my 337c...fewer holes in the boat. I just use the GPS speed, which from most of the reports posted seems to be what most people are looking at for speed.