Fish Finder

What is a really good unit that is not going to break the bank for a Kayak?

What has the widest cone angle?

No maps or GPS needed.

Thanks

You may be under the mistaken impression that a fish finder is going to locate fish for you. The best you can hope for with a fish finder is that it will put you in the right depth of water and or on structure that hold fish. You might see fish on a low end fish finder but you may (probably) not be able to catch them.
With the advancing technology and reduction in price I wouldn't give up entirely on GPS. I have a Helix 5 and I use maps all the time to locate likely locations for fish.

1) its not a fish finder... its a structure finder!
2) I had originally shunned GPS... but with a good contour map + waypoint marking - it is actually super useful to have.
3) SI - rocks

I personally just went from a lowrance 4x DSI to a elite ti 7 - so worth the upgrade. That said - the elite ti is probably more than you want to spend. I'd recommend one of the Hook2 units.

Anything more than a 5 inch screen on a kayak will most likely interfere with your limited space.

Can you still hull mount these?

Take a look at the Humminbird Helix 5. I have the SI with GPS, but they have other models that will fit what you need.

Check out this conversation for mounting of SI units. Recent SI thread

Note: I'm using a Helix 7 with Chirp and SI and I upgraded the transducer to the high def unit. It will mark fish and SI is the bomb in shallow water. In 4 or 5' of water, down imaging isn't doing much for you.

I've seen guys using 9" locators on a kayak with no issues. The larger units are very popular. Don't think that everyone must use a 4 or 5" unit because it is only a kayak. There are many reasons for the larger units, but split screen features are nice on a larger unit.

you can hull mount... yes.. through hull mount - no (not for SI). My personal preference is not to do through hull mounts - i lose to much detail on DSI/SI

most guys here use either some sort of "arm" mount that lets them swing the transducer in/out of the water. I personally am using a magnetic mount right now (from fishfindermounts.com) - but i move my unit between two kayaks and a porte-boat constantly and the arm mounts were getting annoying.

I'd recommend a Helix 7 with Side Image.
I'm running a 10" with no issues of it being to big for a Kayak.
GPS/Maps can be a very useful tool, IMO.
Also a good Side Image unit tuned properly will is very capable of locating fish and you should be able to catch them. They certainly excel in finding structure and cover where fish are likely to be holding.
There are several good ways to mount transducers and a lot depends on the kayak and the Fish Finder.

I have to say that a fish finder is a fish finder! As a professional guide, the 2D sonar is vital to locating fish. The frequency used by most manufacturers is 83 kHz. This provides a cone that is 1:1 meaning in 30 feet of water, your cone will be 30 feet wide on the bottom. The sonar screen will show fish in the form of arches. Arches have size, shape, and color. All 3 determine what type of fish it is. While some education and practice, you can determine the species under you. Sonar is not great at showing structure. Side imaging and down imaging shows the best structure, but isn't great for showing fish. A Humminbird Helix 5 or 7 would be great on a kayak. Don't mount the transducer in the hull, mount it outside so you get the best readings.

A good Side Image set up properly is great at seeing fish, Arches in sonar is history, the fish are no longer under your boat, a straight line indicates the fish is still there. Sonar beams are cones, in 20 FOW and 83 kHz
You'll have a 20' diameter bean on the bottom but for a fish suspended at 10' you'd only have a 10' beam to locate the fish and if you're using 200 kHz it'd be 1/3 that size.