im getting a fishfinder, help

so, I've decided to go for it and get a fish finder, with the idea it may help me catch more fish
Looking around on this site, it seems like humminbird is the brand of choice.  so i am thinking the 365i or 385i  models.
I have seen the Cuda models and they seem to be priced a little better.
what really is the difference here? does one operate a different technology rendering the other supererior in easily observable way? im not that good of fisherman really, but they don't call it catchin' do they? i fish mainly in ponds and mountain lakes, but am wanting to hit some larger east side lakes. Do i really need some of the fancy features of the more expensive models?
I fish from a WS Pungo 120 that i often share with my 23# jack russel terrier, so i dont want something too big, it will be mounted out font on the deck or back a little bit on the side, so it will be over an arms reach away, but will use the RAM mount so there will be a little flexibility.  I wonder about seeing these under full light conditions- anyone have recomendations if this is a problem? built it a billed hat?
I really dont have any experience with fishfinders at all.  I dont know anything about batteries, i guess i need a battery box and a battery? what kind of battery do you buy?
Naturally, being a kayak fisherman, i am cheap. I am also colorblind, and wonder if much of the benefits of the colorscreen will be lost on me- i dont see black and white, but similar shades throw me for a loop. Do the color screens.
please excuse the shotgun approach of this post, but am just trying to gather your thoughts on as much of this as possible. there some some really smart people on this forum and im hopingfor a bit of that knowledge

so, I've decided to go for it and get a fish finder, with the idea it may help me catch more fish

The important thing to realize is that they help you find the PLACES that hold fish!    A quick thing you'll learn with a sounder is that if you try to catch the fish that it tells you is right under you(if it does show you one) you'll probably never catch it.

I feel you on the colorblind thing as I'm sure plenty of guys on this board do as well.  Color screens are awesome and I don't think you'll have any trouble seeing the colors on these screens.  I don't and it seems like you see what I see.

I have a bottom of the line, on-clearance-at-Wally-world, Eagle cuda 168.  It is grey scale and it works just fine.  I don't ever have trouble seeing the screen except when it gets splashed with water.  I guess what I'm trying to say is if you have the extra coin to get a nice color screen, then go for it.  But it isn't totally necessary.  I put more money toward a handheld GPS and I feel that was worth way more than a really nice fish finder.  You can get both a GPS and FF together, but I like having them separate. 

Batteries are pretty simple.  I used to use a brick( 12V gel cell rechargeable) but recently switched to eight rechargeable AA's.  Get a 8 AA cell battery holder from Fry's with the 9V snap connector, put it in a dry bag and that's it. 

RAM is the only way to go for mounting IMO.

Hope this helps, let us know how it goes.
 

Ditto on the RAM mounts.

I've used both an eagle cuda 250 w/gps and now i have a 385ci. Both serve there purpose well but if you can afford the Hummingbird go for it, It is awesome !

BTW, Rawkfish, 8 AA rechargables are only 10.4 volts, for some reason rechargable batteries are only 1.3 volts. You need to add 2 more and you can actually run 11 if you want because most finders can take well over 12 volts. That's where it got to be a pain for me when i was using AA's because i only had a 4 space charger...

Here's the Ram mount, about $35---I may have the bottom 2 pieces of this setup, will sell cheap...

I am still using my 20 year old Humminbird "portable" LCR 400ID fish finder....the darn thing is bullet proof......I "marine gooped" the transducer forward of the mirage drive in my Hobie Outback.....used a Ram mount for the display.
I bought a  Fisher Price "Power wheels" sealed 12 volt, 9.5 a/h battery at wally world for about $55.00.....it comes with a charger and runs the fish finder for "days".
My next fish finder will have gps and most likely will be another Humminbird model due to reliability and nice features.

BTW, Rawkfish, 8 AA rechargables are only 10.4 volts, for some reason rechargable batteries are only 1.3 volts. You need to add 2 more and you can actually run 11 if you want because most finders can take well over 12 volts. That's where it got to be a pain for me when i was using AA's because i only had a 4 space charger...

Good point CBY.  This is something I was pondering as well.  Apparently all alkaline AA cells (and other cells, such as AAA's and C's and others) put out between 1.5V and 1.0V over their effective life.  The largest possible voltage difference they can provide is 1.5V while most of that life happens to hang around in the 1.2V range.  Anywhere you can use regular, alkaline, non-rechargeable AA's, you can use rechargeable AA's.  In essence you could say that the rechargeable ones are a bit more realistic in the labeling of their voltage difference. 

Also, my sounder says it can operate on a minimum voltage of 10V, so I'm all set! 

Sure I'll have to recharge the batteries more often than my 12V brick gel cell, but these are cheaper to replace in the long run and the chargers are getting faster and cheaper.  I think it only takes 4 hours to fully charge 4 AA's with the charger I bought, and that's the cheap one!  They do make eight cell re-chargers so I'll have to upgrade to one of those sometime.  The main reason though was that I was sick of that extra weight that the gel cell has.  I still have it and can still use it since I have a Pelican Box where my battery goes.  I don't think I'll ever be ready to give up that crazy amount of milliamp hours.  So made the 8 AA cell holder so that it can plug in inside the box where the gel cell goes.  I like the idea of having a couple of power options.

I use the 8 AA re-chargeables and they will run my fish finder for at least six hours.  I use the 8 pack holder with the nine volt adapter like Rawkfish. I have another two pack holder that van be stuck to the side with velcro  and connected in series for 10 re-chargeable batteries to get it up to 12 volts.  However, I found that eight re-chargeables were enough.  My fishfinder shows about 10.5 volts when I start, and gets down to about 8 volts when it shuts down.  I carry two set-ups like this and like that they are much lighter than the 12 V brick.  One pack can also be used to run my white nav light in the early morning.  I use the fuse that came with the fish finder.

Another note on making battery packs:

Fry's makes it super easy to make even a 10 or 12 AA cell battery holder.  Hell, you could even make a battery pack for your sounder with C size cells.  That would give you a longer time between charges, but you'd have to consider (1) finding rechargeable C's(I think they're out there, you'll just have to look around) and (2) the weight and size of that would be a pain to the point that you would be better off with a sealed gel cell. 

http://www.frys.com/search?search_type=regular&sqxts=1&query_string=battery+holders&submit.x=0&submit.y=0&cat=0
And:
http://www.frys.com/product/1642841?site=sr:SEARCH:MAIN_RSLT_PG

As you can see, the components to make this stuff are crazy cheap and require very little knowledge of electric circuits to put together at home.  They carry the most common stuff (e.g. AA cell holders) in the store in Wilsonville but you can have anything shipped to the store for pickup if you're in the area.  Slap it together and stick it in a small dry bag and you're good to go.

A vote for the Eagle here, I got the 350 sonar/gps combo, and love it esp the price. Been out to 100 fathoms and still read the bottom just fine. Being able to hit the waypoint button and mark a good spot is priceless, esp. in the salt. I run the AA batteries too, costco had some eneloop brand rechargeable AA's that say they are 1.5v, so 8x1.5=12v. Average about 8 hrs. run time on them, although I've noticed the last hour or two fish arches don't show up as well, I'm guessing due to the voltage dropping.

BTW, Rawkfish, 8 AA rechargables are only 10.4 volts, for some reason rechargable batteries are only 1.3 volts. You need to add 2 more and you can actually run 11 if you want because most finders can take well over 12 volts. That's where it got to be a pain for me when i was using AA's because i only had a 4 space charger...

There was long discussion of this on the kayak fishing stuff board a few years ago. Their resident electrical guy had determined that most ff's ran on 8 volt and sloughed the rest off as heat. YMMV

That said, I use a 12v 7 amp/hr gel cell brick that Fisherman's Marine sells for  less than $30. They think its a deer feeder battery.

For the FF, I like the Eagle Cuda 350 or the Lowrance M56 (same thing). They are little and have tide tables and  currents built into their gps functions. That does not happen again till you spend a lot more money.

They are a tad on the small side and if your eyes are bad and you mount it out of reach, you might want to go with the Humminbird.

There was long discussion of this on the kayak fishing stuff board a few years ago. Their resident electrical guy had determined that most ff's ran on 8 volt and sloughed the rest off as heat. YMMV

That makes a lot of sense.  It lines up with what craig mentioned about how his shuts down when the battery gets down to 8V.  The voltage I got for 8 AA rechargeables was about 10.3V or so after a fresh charge.  I've been running my sounder on it and several hours into operation the battery pack runs about at 9.8V.  So once it gets to low 9's it'll probably start fading.

Thanks for the help.  I am now leaning towards the Cuda model- save  a little coin- and "good enough" is probably all i need- and for 100 buck less is quite a bit.  I just need to fugure out the battery issue.  So they don't sell these "battery packs" for the AA rechargables? im thinking the one of the Gel cells may be where i will look- unless Cabela's has a good solution when im there next weekend. 

Thanks for the help.  I am now leaning towards the Cuda model- save  a little coin- and "good enough" is probably all i need- and for 100 buck less is quite a bit.  I just need to fugure out the battery issue.  So they don't sell these "battery packs" for the AA rechargables? im thinking the one of the Gel cells may be where i will look- unless Cabela's has a good solution when im there next weekend.

If you get a gel cell, make sure you get a charger made for charging gel cells as it will extend the life of your battery significantly. 

im thinking the one of the Gel cells may be where i will look- unless Cabela's has a good solution when im there next weekend.

I don't know whether they will have it in the store, but I'm using this battery I picked up from Cabela's online:
Cabela's Rechargeable 12-Volt Battery

I had just been planning to use rechargeable AA's, but they aren't as cheap as I expected, you have to dealing with charging a lot of batteries, and don't have as long of a charge.  The Cabela's battery seemed like a good alternative, only downside is that the charger isn't regulated and you have to be careful to not overcharge the battery.