Here is something that can have a big impact on your cruising plans. It is a hydraulic crimping tool, used to properly affix electrical lugs on heavy cables. If the correct dies are used, this makes a perfect job.
Ray, the Ventura Harbor Boat Yard electrician, is demonstrating its use. He is fitting a lug onto a piece of 4/0 cable for a rewiring project on our inverters.
Look at the compression on this crimp. Good mechanical contact with the wire is insured, which means minimal voltage drop across this connection. When you think of how many connections exist between the batteries and the devices they are powering, any loss at terminals begins to add up. This means lower voltage, lower efficiency, and less time between recharging.
You can do a good job with hand tools as well. But much greater care has to be taken.