Prowler Sonar Cover

[Tomol]

Looking from help from the group. I just installed my second Hook4 fishfinder. The first one lasted about a year before the plug corroded and became inoperable.

The cover sits too low to see the unit (first pic) so I would go about my day with the cover completely open exposing the unit to saltwater, particularly drips off the paddle. I'd like the cover positioned like the second pic, so it's more protected. But how to hold the lid in position? Suggestions?