This is a complex topic, and there are many differing and contradictory points of view.
Stan Honey's position is perfectly correct ... if all you're concerned about is galvanic corrosion. Unfortunately, there are other factors to consider, each of which interact with the boat's grounding/bonding system. Not all apply to every boat. Some of these factors are:
- Galvanic Corrosion
- Lightning Protection (Controversial in itself!)
- Performance of Radio System's "Ground Plane" (VHF, Radar, AIS)
- Shore Power Safety Ground
- Presence or absence of a Galvanic Isolator
- Presence or absence of a Ground Fault Interrupter (GFI)
You can find "experts" that argue for everything from "Bond Everything" to "Bond Nothing"!
You should try to learn as much as possible, and then make a decision based on your specific situation.