Actually knocked this together when I was working on the boat. I ended up having to have the soldering iron on while using the drill and then the jig saw and the the angle grinder while trying to charge the batteries all at the same time. the plugging in and out finally got the better of me and I went looking what was possible from my box of electrical plugs and wires. and came up with this. I have some of those commercial multi plugs, but they never have the correct mix of what I need. Here in SA we have our own 3 pin plugs as well as the international 2 pin plugs. I also wanted a tell tail light showing there is power up to the plug. Too often I had to get off the boat just because the power was switched off at the wall.
All 6 sides have been fitted with a socket. Also used a heavy 2.5mm Sq wire too the plug although I very seldom run all the heavy consumers at the same time. The center piece is just 2 4x4 surface mouning boxes screwed together.