What's the best way to affix a connector to a marine grade wiring? My friend swears to tinning the connector to the wire. Is that true?
According to ABYC (and in PYS' opinion) all connections are required to have a mechanical means of connection (like a crimp), other than solder. Some folks still like to tin the wire as well, but it’s not necessary and probably redundant anyway. We swear by also using adhesive-lined heat shrink connectors. Not only does it provide a complete waterproof barrier for the wire strands, but it also acts as an extra connection point between wire and connector.
Tinning a connector to a wire alone is simply insufficient in a marine environment. Keep in mind that if the joint ever gets hot, either through high current or excessive resistance, the solder may melt, causing the joint to fail. Also when you tin a wire, the solder wicks up the cable creating a hard spot, which is then vulnerable to failure from vibration.