Wiring surprise

[McGillicuddy]

Finally getting around to rewiring the Seafari and wanted to check everything out so I've been unwrapping anything that looks funky and here is what I found on the 6 ga going to fuse panel... It was working, but... Is this original or someone's creative splice? Looks like a bolt w/slot thru it, a soldered nut, and a ceramic fuse between the 6ga and the 12ga...It was well wrapped in self-fusing tape and looks clean but I think the wire is less than appropriate for bouncing around off-shore. I expect more of the same on the neg cable above it. Is this a common approach, or did this guy work for an electrical contractor?

Any thoughts?

I've ordered a bunch of cable, wire, panels and fuses from Ancor and Blue Sea Systems but not sure where to start after tear out. I have the Calder book and the Sherman book but could really use some real world pics from some of you guys that have done this on a Seacraft. Can any of you post some pics of your recent rewires? Thanks