I don't pretend to be a technological expert of ducers.Your 77/200 khz ducer refers to frequency, not angle. Regarding "perfect cone"? I assume you're talking about the actual mushroom shape?Re: position of the ducer, 90 degrees to the stern is what you're after. Obviously, your depth reading will be inaccurate other wise.
Funny I kept thinking my line popped out of the release because the line was at such a different angle and the bend kept disappearing even after I tightened it. but when I stood up and reeled in a bunch of line I realized a ton of it was just bowing out. When I tried to pull the line free I couldn't eventually the line snapped because it had wrapped around the cable too.Still learning! I hope the Chamberlain releases make a different here.
Also try rubber bands thin ones!! Instead of the release..
Might need a custom rigger clip.
I'll check out the rubber band method. I twisted the line and made the loop using the chamberlain release. It still wrapped about the cable and snapped! I wonder if it happens if/when the boat stops.