Enough of you are into lights enough that this seems to be the best place to ask.  The cool thing is that you also tend to do well at pointing out inexpensive options.

Do any of you light aficionados have a suggestion for specific light bars I should be looking at to mount to a flatbottom boat with a surface drive motor that is primarily used on the river. Amazon has a bunch that seem like they would work, but I figure it is a good idea to ask here first.

I want something that cost effectively throws out a lot of light, a long way. My Convoy C8 flashlight worked well last year, but it is time to get something bigger and more permanently mounted.

I have a small LED box light on my truck.  It's water resistant.  The real question is how much of a thrower (distance of light projection)?  That will determine the individual LED wattage and reflector design.  And if you need both throw and flood functions..

I do have to say that even the small box on my truck (which is more flood, my big fenix light has more throw), it drains batteries quick.  I have a separate battery with a low voltage cutoff for my flood.  On a boat, you'd never want to run the battery flat and be stuck out somewhere.

I have two of these Nilight 22" bars on my Kubota RTV - MASSIVE amount of light coming out of these bars.  Color me well satisfied with the amount of light.

https://www.amazon.com/gp/product/B012CGFOOQ/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1&tag=vglnk-c102-20

Good luck!

Thank you, Gentlemen.

A couple forums mentioned Seward...cost effective.

Check your local laws, I know here we can have a mounted light to drive with. They've even stopped people with "docking lights" (leds that only throw a few feet) and had them turn them off.