Nerd paddling metrics bliss?

Since the GPS topic came up again recently, I thought I'd post some of the things I've found out... To cut to the chase, the following charts from today's outing show speed, heart rate, cadence, and distance per stroke:

The outing consisted of 4 miles upwind where I tried to stay below HR140, then turn around for 5 miles DW where I wanted to stay in the HR140's, and a final 1.5mi back upwind to the harbor.

It was way too rough to meaningfully use the cadence info, this was more of a test to see whether I could actually get it all to work.

The equipment is all on the "budget" end: a Garmin Edge 130 for USD200, a Polar HR7 strap which I already owned, and a cheap $15 cadence sensor. A nice thing on the Edge 130 is that one can display many data fields and they can be customized. So I can see the cadence in real time and I can program another field to show distance per stroke in real-time as well. What doesn't seem to work well is cadence when going downwind: either the sensor or the edge show too high a cadence when I stop paddling and am just bracing. I'll see whether I can figure out which of the two is doing this.

Here is another set of charts from yesterday where I did some 4 minute intervals with a friend going upwind. These don't have distance per stroke because I hadn't figured that out yet:

I intentionally did the 4 intervals at different stroke rates to see the differences: around 29, 28, 43, and back to 29. I tried to stay around the same max heart rate. I didn't go faster at 43 than at 29, but my heart rate went up more quickly . All this was in too rough water to get meaningful data.

Overall, I don't know whether all these numbers can tell me anything unless I do time trials on flatwater, but it's cool that one can this without totally breaking the bank!