I rewired my boat 5 yrs ago. So far no issues. You should consider splitting your circuits into port and starboard. This way if you have a problem at night with one side chances are the other side will be OK.
I ran one continuous duplex line (10 AWG) down both sides of my boat. Then near amidship I install a fused BlueSea circuit hub. This way I could add or subtract devices at will and have them be fused. This works well if your lights are switched at the device. The reason I used 10 AWG is so I could add fans or maybe 12 volt taps at will without worrying about voltage drop.
Make sure you use stranded tinned wire, also get yourself a good pair of rachet crimpers for insulated terminals. West Marine
sells a very nice kit that have interchangeable jaws for different connectors. It's not cheap but you will make good crimps with no worries. The only thing I don't like about them is they are only a single
crimp. Double crimp crimpers are better because they crimp the wire and insulation
. Also before you crimp the connectors make sure you coat the wire with dielectric grease. It will protect the connection. When you are done with the crimp give it a good tug to make sure it's secure. I did not use heat shrink on any connections inside the cabin
. I know it's recommended, but I think with the grease at the connection it does the same thing. If I was wiring anything running through the bilge
I would definitely use heat shrink tape.
When connecting my lights I had trouble connecting the #10 wire to the #18 or 20 GA wire on the light. You should use quick connects with male and female connectors. This way you can keep track of polarity. A 10 AWG female connector will work with an #18-20 male connector, the blades are all the same width so it makes it easy to connect larger wires to smaller ones plus if you have to remove the fixture they are easy to disconnect.
Try to leave a service
loop where ever you can so if you do have to fix a bad connection, you have extra wire.
You should run your wire in some kind of conduit such as flexible bilge
hose. It protects the wire beyond the sheathing, allows you to add wire in the future and reduces vibration which is the enemy of your connections. I cut it lengthwise and then screw it to a bulkhead.
I heard this quote from a retired NASA engineer
I met in Florida
"If a job is worth doing, it's worth overdoing".