I have no expertise here, but I was wondering if the low confidence in surf is due to bubbles? (I took a quick look at the transducer and software docs, but did not see anything explicit about the confidence figure.) If it is due to bubbles on the underside of the board, perhaps putting the transducer in the middle or behind would help? If it is due to bubbles in the water column, it reminds me of something I learned about lidar mapping: you may get reflections from the tree canopy, the understory or the ground, but in any small area, one can assume the longest-in-transit is probably the ground (and you can sometimes figure out the height of the other layers as a bonus.)
I have no expertise here, but I was wondering if the low confidence in surf is due to bubbles? (I took a quick look at the transducer and software docs, but did not see anything explicit about the confidence figure.) If it is due to bubbles on the underside of the board, perhaps putting the transducer in the middle or behind would help? If it is due to bubbles in the water column, it reminds me of something I learned about lidar mapping: you may get reflections from the tree canopy, the understory or the ground, but in any small area, one can assume the longest-in-transit is probably the ground (and you can sometimes figure out the height of the other layers as a bonus.)