SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

What is this black stuff?

3K views 13 replies 8 participants last post by  sailaway21 
#1 · (Edited)
We have a leek in a 1987 Catalina 27'. We started grinding and this picture shows an area at the very top of the keel on the starboard side about in the middle of the boat. This boat has a glass skeg keel of about 12” with the lead keel affixed to the bottom of that. The lead glass joint looks good. This picture is taken from the center of the glass skeg on the starboard side about in the middle. From the bottom looking up the picture clearly shows:
1. Red bottom paint
2. Gel coat,
3. Large Dark green band (very hard)
4. Small White band (Caulk like but rather soft)
5. Large Black band (Like putty very, very soft)
6. Tan, Pink (Very Hard)
It looks to me like #6 is good glass.
What is #5 it is worthless?
What is #4 it is not much better?
What is the #3 layer
The two layers of softer material white and black (about 1/8”) is between the solid dark green layer and the tan pink layer #6 from the shaft log to as far as we have ground, which is now mid keel.
Also about half of the #6 layer is spider cracked and crumbling and we ground through the hull.
This boat was grounded before by the previous owner and repaired by the yard in an area of about 6” by 24” primarily with bondo directly behind the keel.
 

Attachments

See less See more
1
#4 ·
1. Red bottom paint
2. Gel coat,
3. Large Dark green band (very hard)
The green looks like fiberglass. Fiberglass is often greenish or pinkish.
4. Small White band (Caulk like but rather soft)
No idea what this stuff could be... best guess is that it is sealant of some sort.
5. Large Black band (Like putty very, very soft)
This sounds like it was wood or some other organic material that just rotted.
6. Tan, Pink (Very Hard)
Also, looks like fiberglass. As I said above... Fiberglass is often greenish or pinkish.
It looks to me like #6 is good glass.
What is #5 it is worthless?
What is #4 it is not much better?
What is the #3 layer
The two layers of softer material white and black (about 1/8") is between the solid dark green layer and the tan pink layer #6 from the shaft log to as far as we have ground, which is now mid keel.
Also about half of the #6 layer is spider cracked and crumbling and we ground through the hull.
This boat was grounded before by the previous owner and repaired by the yard in an area of about 6" by 24" primarily with bondo directly behind the keel.
 
#5 ·
The soft caulk like stuff, maybe boatlife. I had it on my boat around the cutlass bearing tube.
 
#7 ·
Hmm... the plywood would be a good candidate for the black stuff...especially if it was rotten. :)
 
#8 ·
This shot is from the starboard stern side. A couple of inches out of frame to the left is the engine saltwater intake. The first shot it at the same elevation (just at the point where the bilge of the boat curves down to the skeg) about 6" to 12" to the right.
I just never expected so many colors and donn't know what they mean. The black spots under the hole are solid so the blackness itself may not be evidence of rot.
 

Attachments

#10 · (Edited)
Yes. This location is a few inches forward of the engine water intake. It was covered with the soft black layer and had soft glass underneath so it had to be ground out.
Some of the black layer is hard Some is hard and over solid glass, some is soft over solid glass and some is soft over delaminated glass.
I'm leaning towards the theory that it was repaired more than once. That would explain the normal glass at the deepest layer and the blue glass near the surface. Still donn't know what the black layer is.
Plywood sounds unlikely but maybe if they used a plywood form to cover with glass.
 
#11 ·
The bottom of the keel stub of the C27 consists of a plywood board, and the keel is through-bolted to that board. The plywood is encased in fiberglass, but occasionally the seal can get broken, such as in a hard grounding, admitting water, and causing the plywood to deteriorate. The plywood can be replaced, and it can be done by the DIY'er. Catalina used to have an instruction sheet, that shows how to do the job, if in fact it needs to be done. I suggest you contact Catalina, show them your photos and ask their advice.
 
#12 · (Edited)
Like Sailormon6 says, the keel construction is (from the bottom up) lead keel, 5200 sealant/adhesive, fiberglass, plywood and then fiberglass that is visible from the bilge. I have the aforementioned sheet from Catalina that shows the keel stub construction. Let me know if you would like me to email it to you.

From what you are describing, it sounds like the black layer is actually part of the hull layup in places (since you had to grind through it to get through to the bilge), and if that is the case, I agree it sounds like something used in a previous repair.
 
#13 ·
As the pictures show the black is not consistant with the edge of a piece of plywood. It is a layer over a significant part of the hull. My current theory is that the black part is a layer of a prior repair that went wrong. Maybe glass that got too hot. Some kind of patch material improperly applied or cured. I can't imagine what happeded exactly as I have not seen a layer that looks like this before.
 
#14 ·
I'm thinking it's moisture damage either within the plywood or the glass as well in the area around the plywood, and that, at a minimum, the full extent iof it must be revealed and repaired properly. It might be that replacement of the plywood would not only be the best way to approach the project as a whole, but the lack of doing so in a previous repair is what has led to the apparent migration of damage.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top