the current also traveled through the fiberglass hull and exited the gelcoat. The captain of an adjacent anchored boat happened to see the bolt exit through the sides of the hull. He called over that he saw 'fingers' of light traveling outward through the water.
The link below shows the "fingers of light" duplicated in a lab (I took these pictures). At the bottom, you can see the same experiment done in both salt and fresh water, the fingers are much longer in fresh water. http://analogengineering.com/lightning/surface.html
Interesting that the strike in the quote happened in fresh water. The lake I sail at is at 8600 ft elevation so is very fresh water. There is a fair amount of lightning in that area and a lot of fishing boats and I have asked the old timers in the area if they had ever heard of a boat getting struck. Nope.. in many, many years, no one knew of a boat getting struck. However, people have been stuck at the shore line and there is plenty of evidence of tree's that were struck.
The storms come through there fast and I would be out on the lake in a sailboat. All the power boats would head in and were much faster than I so I would have to just throw out an anchor and wait.. I think I may have been at higher risk anyhow of receiving a strike at the boat ramp (at the interface of the water and land.. nice wet conductive soil).