While I was laying on the ground scoping out the hull for the thru hull transducer location, noticed the edge of the keel in spots didn't look right, the bottom paint didn't cover it good enough. Pretty much here and there the whole keel, on the edges. Any ideas, cause, fix?
36-80 grit for the abrading, making sure to get down into the deep spots, a wire wheel might be good for those.
Rage or another filler that doesn't absorb water would work nicely.
80-100 grit for the fairing.
Any bottom paint that you've had good luck with should continue to perform well for you.
Probably where it slides along the keel on your trailer, looks to be an air pocket during lamination that someone missed. Not the end of the world. Just fill it in and sand it fair, paint it to keep the creatures off of it and maybe make a softer bed/entry for your trailer.