Speckhunter,
Not that I wouldn’t want you to buy a new Humminbird unit… but:
A new 787c2i is going to run you about $650.
A power cable, unit mount and transducer will run you far less.
PC-10 Power Cable ~ $11
MS-M Unit Mount ~ $33
XTM-9-QB-90-T Trolling Motor Mounted Quadrabeam Transducer ~ $75
( XTM-9-20-T Trolling Motor Mounted DualBeam Transducer ~ $60 )
Your choice. Advantages of having the second unit would be that you would not have to move the one you now have back and forth everytime you stop to fish or make a run and you would have a back up unit - just in case.