I have a 16 ft tracker grizzly jon boat.  I'd like to install some type off bilge system just in case.  It is an electric only boat, with 2 batts in the rear of the boat for the transom TM.  I've seen 2 kinds in the store - automatic, and non-automatic.  What type should I get?  Also, installation instructions would be great.  Last thing...is there any way to do this without drilling  a hole in my boat for the discharge hose?

You should be fine with manual.  Automatic is required if you are gonna be mooring for a while.  With manual, you have to see that there is water in the boat, and go to the trouble of hitting a on/off switch.  IMHO, go with a manual.  You could probably get by with a 250 gph as well.  It is not like you are taking waves over the bow in an electric only lake.  You can mount it with the hose discharging over the side.  But, the higher the pump has to push it, the less efficient it is.

the manual one is just fine. add a switch and your in good. you can just run the hose out over the transom. That is how i do it on my 14 footer. I didn't want any holes, so I run it over the transom and hold it in place with some wire ties. 500 gph seems to be the norm, that will do you fine.

I just hooked up 2 500 gph to my boat.  One was a replacement, and I added one under the floor to the existing hoses.  I also hooked up a float switch so they would be automatic and I also hooked up a toggle, so they could be manual also--just incase I can't see the water or if it is raining and I want to leave them on.  I used a marine sealant around the edges to fix them in place--had to use a brick to hold it down while the seal set.  I would just clamp my hoses over the transom.  The manual or automatic is how much shuffle you want to do to turn them on, or if you are positive you will know there is water coming in.

Friend has one and used PVC pipe to go up and over the transom. Made for a neater installation than a soft hose - used the elbows etc...doesn't have to worry about it getting kinked or caught in anything. Just made it go straight up and over and back down about an 1" - just enough to "hang" on the transom.