fish finder suggestions?

[lowprofile]

i was going to get the mark4 sonar/GPS but the guy who was supposed to by my fish tank bailed on me so i dont have the funds right now...

anyways. what are the better units for kayaks out there? i want something with clear imaging to 300ft (would be cool to have something that reads to 600 or more) and has GPS that i can save points on.

also going to run two batteries. one for the FF and one for the bait tank. figure this will give me more life on both for multiple day trips and allow me to run a color unit with GPS assuming it takes more juice.