Lightning Strike and Bottom Paint damage

kloudie1 · Oct 10, 2012

My boat was hit in slip. When we pulled her to do bottom paint, I found strange places where the barrier coat and bottom paint had "un bonded" .. No problem with the hull paint, only the keel.. I am thinking that a lot of electrons left that area..

victorhoisington · Oct 10, 2012

My boat was struck 3 years ago. The lightning entered through the hull from the top of a plastic fender that was rubbing against the hull but hanging clear of the water. It exited at the bottom the fender about 3" above the true water line, exploding a bag of chips across the cabin. Surprisingly, no electronics were hit or damaged. That is the lucky part

To repair the holes I planned to grind out the two holes and make minor gelcoat repairs. In reality I found that the fiberglass aroudn the top hole had delaminated and ended up repairing a section the size of a small dinner plate. Grinding down to "solid glass" and then patching the hole along with new gelcoat.

Fiberglass, glecoat and paint will all be affected by where the strike "left" the boat and got to its final grounding point. Often this would be through the keel, but not always. Lightning is a funny beast, it has a mind of its own and will go where it wants to go. If you can prove that where the blister is is where the strike exited the boat, you should be OK. Look for burn spots or other damage on the inside of the hull that coorespond to where the blister is. You may also need to test the hull, while it may look good on the outside look for any delamination of the fiberglass in the same spot. If the various layers of fiberglass and gelcoat were affected there may be some delamination which should be repaired.

I now have an appreciation for both lightning and the guys who can match gelcoat colors. Fun to do but not something I'll ever make a career at.

Good Luck

Victor
French Temper
Hunter 28

PaulK · Oct 12, 2012

Lightning strikes have been known to cause superheating and vaporization of water in the path to ground. Wooden masts, for example, get blown apart in miliseconds by the expanding steam. Could something like this be going on - moisture between paint layers turning to steam and causing blisters? The water you found in them afterwards could have seeped in after the strike. Is it fresh or salty?

petersea · Oct 14, 2012

Nautiflyer said:
My boat was hit by lightning (no one was on it), and as predicted, lots of electronics were damaged. One puzzling item is the bottom job. The bottom paint “blistered”, the gel coat was intact, and much of the “original” paint stuck, but the 5 or so other layers popped loose and created a “blister”. Water was in these, and when pressed, the water came out the surface cracks in the “blister”
My Insurance Company and I are now at odds. Has anyone experienced this type of damage?
Mike

What exactly are you at odds about? I suspect that you are wanting the bottom stripped and redone ? IF this is only bottom paint and no damage to the hull gel coat/fiberglass I think especially with five layers of paint the insurance company is most likely rejecting it based on it is maintenance or improperly put on or defective paint . You need to show that it was damaged by the lighting strike. If needed get a second opinion from a good marine surveyor and maybe some info from the paint manufacture as to if this could have been caused by a lighting strike. Not sure where you can or will end up as it may not be cost effective for you to fight this out. I would be more concerned that there is no damage to the hull first then worry about the bottom paint. Maybe post some pictures ? Is this the entire bottom or to what extent is the bottom paint damaged ?