You absolutely need to ground your aluminum arch for safety reasons. Both your solar panel and wind generators are connected to you batteries via charge controllers (all 12v), but your 120 AC power battery charger
is also connected to your batteries as well. While rare, either a lightning
strike, or more likely a voltage spike, or malfunction
can cause a short/ issue with the battery charger
(especially transformer-less 'switching' chargers) which can result in lethal 120 voltage 'leakage' into its 12v DC line. Anything that is metal on a boat that has either DC devices (or AC devices) connected/ mounted to it must be grounded to the ship's ground (usually the engine
block). It is also the attachment point of your electrical panel green (ground) wire. Every solar panel, wind generator
, sat/ TV/ radio antenna
is designed knowing if it is mounted to metal, it is ground to the ship's ground. This ensures that all metal objects on a boat that you can touch with wet feet/ hands are electrically bonded together and at the same zero potential. Keeping everything bonded actually reduces electrolysis issues.