Fenix 6 SUP reads zero km/h when speed is constant

I have found others with the same issue due to the HRM Pro settings, have made the change and will test again later in the week

I do not SUP, so I have no experience of this phenomenon, but I do have a theory. You wear the watch on the wrist, so when you paddle you draw the wrist backwards. The board moves forwards, but your watch moves backwards, or perhaps stays still for a moment as you pull the paddle backwards. Depending on style of stroke and speed of board maybe this is enough to upset the pace calculations.

I don't know where you place your Edge 130 for your comparison, but I guess not on your wrist. Also, it probably has different pacing algorithms, designed specifically for a bike, with higher speeds and a more consistent direction of travel.

So, simple test - start a SUP activity on dry land and walk at normal SUP pace. Do you still get the pace dropouts? If not then my paddling theory may be correct. How about if you walk, but simulate a paddling motion, with long back sweeps of the watch. Any difference?

And FWIW I just tried exactly this test with walking whilst recording a SUP activity and I think it confirms my theory. Not a perfect demonstration, because I was walking small circles in my back garden and GPS did not get a good soaking. Even so, pace is very uneven when I simulate paddling and somewhat better when walking normally (first walk) or holding the watch steady in front of me (second walk). Note that pace gets ruined once there is a stroke rate recorded.

Alternative view, maybe clearer to see....

Even if this is the case, it worked before so Garmin compensated and needs to do so again. Or this is not the cause and it just needs to be fixed. Either way, a fix is needed.

And the user shows a graph showing a complete stop, when I'm paddling with 8kmh I'm still moving forwards even if my arm is slower on the downstroke, it's not a complete halt. And it does not look like a stroke pattern on the graph.

Actually when running or walking the arm has wider range of motion compared to paddling (correctly) and it's not a problem there.

The issue is with 24.10 still present. So it looks like a regression of this bug since in 23.00, 23.10 this bug was supposed to be removed. Indeed, with 23.10 I had a SUP activity without any pace issue (but this activity was not representative to my normal SUP activity - other board, with significantly slower pace and instead of HRM Pro I had old Wahoo HR monitor). With older version of FW it worked as expected.

@eezytiger Many sports have periodic hand forward - backward motion. Accelerometer is usually mainly used to estimate cadence (running cadence, strokes per minute, etc.) and then from cadence it tries to estimate the pace, especially in cases when there are GPS signal issues. GPS itself is far from precision to be able to be affected by hand motion. Especially with poor GPS that F6 has. There also should not be reason to be only affected by backward component of the motion and not by forward component of the motion. But with Garmin, you never know...

I was not using HRM-PRO. I was using only the wrist HR.