Considerations

When designing a grounding system there are two important considerations to take into account;

Conductivity is a crucial issue when designing a lightning protection system as resistive materials such as stainless steel, bronze etc. will heat up considerably when current passes through them. The best example of this is the electric stove element. In this example a steel wire is used as the heating element because it is highly resistive and has a high melting point. When current is run through it, it heats up and provides the heat we have learned to rely on to cook.

When it comes to a lightning protection system, the same principle applies. All elements of the design including the inter-connection between components are crucial. For instance, all contacts or connections that are poorly established are potential resistance points. These can heat up because of the impedance (resistance to ground) and fail. This second point could be illustrated by a poor electrical connection in a house wiring system. These are often the cause of electrical fires because they are so resistive to current flow that under load they heat up to the point of setting the wire jacket on fire. On boats, the resistance of the ground path can cause dangerous side flashing and overheating of the electrical conducting medium.

Essentially, the lower the resistance to ground, the more efficient the grounding system. Always consider the materials that will carry the energy and how they are inter-connected to all parts through which lightning energy will pass.

Important Note 

The use of a sintered bronze Radio Frequency Grounding Plate is NOT recommended as a means to grounding lightning strike energy. Plates such as Dynaplates are porous and essentially designed to ground all radio communication devices onboard. When such a device is employed in a lightning protection system, it runs the chance of flash overheating due to its resistive base material and could explode from the instant steam that it could generate from the overheating.

This type of plate is meant to be used as a Radio Frequency (RF) ground, NOT a lightning protection system.

Here is what  Newmar has to say about their plates:

Ground Shoes
* Provide an excellent noise-free RF ground by making direct contact with water on the outside of the hull.
* Porous construction magnifies contact area - see matrix for surface area  equivalent
* Silicon bronze hardware provided (Not intended for lightning protection)

If you wish to install a permanent lightning ground plate, use only extruded electrolytic copper bar stock.