In a past life (And still part of the current one!) I was a communication engineer deploying radio/microwave systems on towers and tops of very high building where it was not a question of if you would get hit by lightning... Just WHEN it was going to happen and did you think of every possible point where it may find a weak spot. It got to be a game for me but, if I was wrong or failed to consider all aspects, would result in downtime of a large radio system or police department which had a dim view of their radios not working... Needless to say I got really good at it and factory certified by Polyphaser and a few others... The police department where I live is a system I designed so in order not to get tickets or dirty looks... Nuff said. Here is my experience with the stuff and food for thought only.... You cannot stop the lightning bolt/charge... just direct it to where it will not do damage and that is the whole trick. Arriving there has been open to interpretation and too many theories but bottom line is you want to make the equipment look very undesirable as a path while providing something to give a hand wave to the lightning and say "come and get me! I'm yours big boy!" How's that for an opener? Don't get caught up in the fact that you may have a fiberglass hull so put that out of your mind for now and picture a mast with a lightning rod on top at some elevation that may be floating above ground (Boats don't have masts that go directly to the waterline) which also includes antennas (Any kind) plus wiring that we want to isolate from all this and should be treated as a separate issue. The big trick is providing the most direct path from the base of the mast then coupling it to the water... salt or freshwater (in the presents of high voltage freshwater conducts). What I wouldn't do... Rely on any one technology to do the job... Only combinations work. Dynaplates were specifically designed to provide RF (Radio Frequency) coupling to the water... Not ultra high current/voltage lightning due to it's construction (beads of metal soldered together) on a fairly small bronze plate. Add high voltage/current and it could blow apart if completely relied on. I have long been an advocate of a large solid bronze plates to act as the lightning ground and dynaplates to be used for what they were intended for... Not someone's interpretation. Bottle brushes on mast tops work... multiple spike rods work... Anything to discharge a buildup. As long as they have a solid path to ground to dis-charge what they have collected. Don't care what is said negative about them as I bet "they" do not have a 300 foot, a 200 foot tower in one location and a 200 foot and 100 foot tower in another for watching sparks fly when lightning is discharging. Too many times I have seen boats with a brush added without any effective dis-charge path... Again the bottom line of giving lightning or, in this case, the buildup of a lightning charge somewhere to go. One method I have used in the past is to take a 3 inch strap with a 4 gauge stranded copper wire soldered down the middle of it starting from the base of the mast and two runs...one port and the other starboard around the cabin and hull down to a pair of bronze plates 3 feet by 2 feet and tie off the strap to them via thrubolts and also tying the plates to each other.. Sort of a circle from mast base to plates with few sharp turns. I don't now if these plates are commercially available but we were able to get them made up locally. I would think that some keel coolers would offer the same surface areas and thickness to handle lightning duty. Again, food for thought. De-coupling coaxial cable wiring is simpler than you may think... Lightning does not like to travel in circles at all... When you coil up coaxial cables they appear as a very high impedance path (or time delayed) where if lightning were given a more direct discharge path simultaneously, would take it. On my installation jobs where I am putting antennas on a mast, I will ground the coaxial cable shield to the mast at the top and again at the bottom where is comes out, coil up 7 to 10 turns 6 inches in diameter then run the cable to a grounded lightning protector (Grounded to our main ground) to provide path delay and not clobber the protector with too much current so it can survive for another day. DC wiring is handled a little different but the same rules apply. One trick I love (started by the phone company like 100 years ago) is to spiral the positive/negative together and run it where ever.. (Drop me a mail on how-to make this) Several reasons for doing this... Reduces electronic impulse noise to/from the cable, keeps it neat and will not radiate or act as an antenna (Important to your SSB Receiver) After prepping the wiring like this down the mast, coil it up like the coax and ground it to the mast base then to the same ground block as the coax. There are DC protectors available too if you really want to get into it! By doing all of this you choke off any unrestricted paths from the mast into the innards of the boat protecting sensitive electronics and you!!! One thing I am going to work on is getting this stuff out of my head and on to my website with some diagrams to show all of this!!!! Hope this helps fuel good ideas. John