I've been in your shoes...... Here's what I did....
I offered a $1k reward for ANYONE that could just FIND the ski.. Find it, I'll dive down and recover it. I had about 25 people all coming out to the lake, I kinda knew where it was but NOBODY could find it even with nice sonar etc. So day 2 I upped the reward to $3000. I sat at the boat launch and as guys with big sonars rolled in, I told them about the reward. Many scanned for 15-20 min before giving up and head out to fish. 1 guy in particular said "I don't even know how to use this thing, I'm going next week for training by the Hummingbird rep and tuner" apparently theres tuning to do with these. He gave me the guys number who lived 2 hrs away. I called and told him about the reward, he said it would be 3-4 days before he could come up.
20 minutes later he called back and said "I'll be up there at 7am tomorrow morning" he realized anyone could find it and get the reward.
He was there early, scanning, he went over the same spot 3-4 times and thought it might be my ski. I looked at his sonar and couldn't tell at all, and didn't think it was my ski but I went back to shore, geared up and when i was gearing up he went and scanned more, came back and said he was 100% sure that was it. it had floated at an angle from 25' to 50' of water vis went to zero and zero light at 15' but i just tied a rope to his anchor line and walked around his anchor, then let out 2 more feet and walked around again and bam! there was my hull it shinned... tied a line to the pole and we pulled it up and drug it in.... best $3k I ever spent!!!
3 days on the bottom, took it straight to the shop, dumped all the water out, sprayed it down, opened ebox and dried it all out, and took it straight to the lake... motor lasted another year of beating on it...