What is this hull bottom coated with?

[twomey]

The bottom has blue bottom paint with a red coat underneath. What you see is after scraping all the loose paint off. What is the surface below the red paint ? Doesn't look like gelcoat or a barrier layer.
Tim

[Carl]

It is common practice to paint bottom with a hard bottom paint of a different color. Then an ablative paint over that. When you start to see the different color it’s time for new paint. It looks like maybe the prep work for the blue was lacking, therefore poor results of adhesion?

[twomey]

Thanks, but I'm not confused about the blue and red coats of paint. What I'm trying to figure out is what is the material where all the paint is gone. The area that looks tan/brown with black spots. It is not paint, it is hard and shiny and smooth. What I expected below the red coat was gelcoat or a barrier layer. That area sure doesn't look like gelcoat and I expected a barrier coat to look white or gray. I have never seen a bottom with a material that looked at that.

[MerryKate]

Hard to tell from the picture, but I have a black gelcoated hull and that's the appearance when scraped/sanded down to bare gelcoat. To my knowledge Albin did'nt barrier coat in the factory, unless a later owner would have done it.

[Norseman]

Had my bottom soda blasted down to bare gelcoat and it was white, or off-white.

[Tree]

Had my bottom soda blasted down to bare gelcoat and it was white, or off-white.

Mine was green. Normally boats over here have clear gel below the water line as the pigment in gel can cause osmosis.

It looks like a barrier cost to me. There is a product here called VC tar or used to be that is the same colour.

[twomey]

Thanks everyone,

Based on the replies, I'm thinking the black 'marks' are really the original black gelcoat. I couldn't find any images of VC tar, which was a one part epoxy primer, but International paints still sells VC Tar 2, a two part epoxy primer which looks brown/red. This is a 1995 black hull. Maybe the VC Tar coat is wearing thru (or was scraped off during bottom paint removal), leaving the black marks. I read that I can put an epoxy barrier over the VC Tar, so I'm thinking if I finished cleaning the bottom paint and sanded, I could start over with a new barrier layer and bottom paint.
Tim

[Norseman]

. Mine was green.

Will look for pics and post: After the most expensive yard in town stripped my boats bottom.
Stay tuned.

[RobS]

....I'm thinking the black 'marks' are really the original black gelcoat...

The hull is original factory black gelcoat? So why would you think the black underneath it all is anything but the gelcoat?

[Norseman]

This is my bottom after soda blasting.
(Boat’s bottom actually)

5E309D1B-55FA-4C22-9381-6743CF3388E6.jpeg

[twomey]

....I'm thinking the black 'marks' are really the original black gelcoat...

The hull is original factory black gelcoat? So why would you think the black underneath it all is anything but the gelcoat?

Black gelcoat is what I expected to see, but what I saw was a brownish surface with some black marks. Looks like it might have been brushed on. I thought the black marks might have been black gelcoat below the brownish surface. I have since been able to examine the boat again and found the brown areas with black marks feel smooth. There is no height change between the brownish surface and the black marks that I can feel. Maybe it's the VC Tar coating.

[Rick B]

Is it possibly a sand less primer that is applied to the gelcoat before bottom painting?