What gauge wire you guys using to rig?
 

12gauge is good? Battery box for fishfinder? Bait tank and maybe fancy Bilge pump

14 at most.

Electrical rule of thumb if splicing stay with the same size or larger, if you are
wiring new 12-14 would be fine.
I would recommend solder and shrink wrap all connections, and try to use
a good marine or weather pack type connectors

14-16

sounds good guys

What I been doing for a long time now. When you solder make sure you use the better heatshrink that has some glue in side that melts and seals better. I also used some hot glue. After I solder the wires togher I would put some hot glue on the soldered wires and then the heatshrink. The glue would melt inside the heatshrink and seal it completly even if you submerge it under water. Worked for me for years, Rewired part of my dads boat. None of the solders ever failed for the years he had it.