Are there any submerged trees you know about or are there trees underwater and can see the tops only above water? These will hold crappie to find without sonar. Any visible structure will hold crappie so you have to know where some may be without sonar. Try these sites. I did a Google search for LOP crappie spots and got these. Do a heavy search Here at C.C and you will find reports elsewhere by doing a google search deeper looking at any and all reports posted on internet.
If you have a phone you can view Navionics app and see the depth of lake in real time. You can use the GPS function of your phone to find the GPS spots from the website below. Here is a link for the Web app to see from your home computer...https://webapp.navionics.com/#boating@6&key=%3F%3F
https://tpwd.texas.gov/fishboat/fish...nal/lakes/lop/
https://tpwd.texas.gov/fishboat/fish...tructure.phtml