Create a new activity-type by copying "Indoor Rowing", then rename it "SkiERG."
To be clear: I'm not sure this is the best solution but it would give you an activity with similar settings and data fields to indoor rowing - stroke rate, GPS "off" etc - under a new activity name.
Another option: download the ErgData app for your smartphone and connect it wirelessly to the PM5 on your SkiERG. Then, set your Concept2 account to sync with Garmin Connect. The result will be all data from the PM5 syncing with Garmin Connect. You don't even need to wear the 935 for this. (wear a chest-strap HR sensor connected to the PM5 via ANT+)
That works but does it get the activity registered for Training Status? As far as I know, it doesn't
No, physiological metrics must come from a Garmin device.
The solution here is to double-log.
Record the activity as general "cardio" (and use a chest strap since wrist HRM is entirely unreliable for any activity involving grip strength), and in ErgData, with your Concept2 logbook set to sync with Garmin. Start and stop your watch at roughly the same time.
You'll end up with two entries for the same activity - one natively Garmin, the other synchronized from your Concept2 log.
The physio data (including training load, training effect, recovery time etc) will come from the Garmin native activity but the precise SPM, distance, power etc comes from the Concept2 activity. (as C2 equipment has accurate power meters).
DELETE the Garmin native activity. Your physiological metrics are "sticky" so deleting the Garmin native activity won't affect them.
