Basic Lightning 101:
Lightning is built up by static electricity if the condition are right in the atmosphere. On any given day, when the charge builds up to such a level, electrons look for the center of the planet (big molten Iron Ball) to connect to.
If you are unlucky to get between the source of the charge and the center of the earth, you get a brand new hairstyle (if you survive)
The charge on most lightning strikes can be in the Billions of Volts.
Grounding a Mast?
Not even worth considering it for the AI/TI. There are so many wet lines, metal contacts between you and the surface of the water, that there is no insulation to stop the arch that would hit the top of your mast and try to find the easiest way to ground. Considering, your cockpit is in the way... the charge will most likely zip down the mast and connect with the Mirage drive (path of least resistance)
On that concept, if one was to be stuck in a situation where there is overhead lightning (light and sound are the same), your safest place might just be on a tramp if you have one. Your wet suit, dry suit may help to insulate you (if it is dry). If you can try not to touch any metal, this might increase your chances.
But never allowing youself to get caught in such a dire situation in the first place might be far more realistic for survival.
However a 10 foot section of thick electrical cable that you can clip on your mast, wouldn't be a bad idea in areas that are prone to Sudden Lightning Storms.
Just some spare Electrons discharging from my head into this 'puter, to the Net, and eventualy going to the center of the planet (hoping)