Ferro project advice

[Wogboy]

Hi all, new to this forum and needing advice. Many thanks in advance.

So here's the story-

I bought a 47ft ferro boat at an absolute steal! Being relitively new to sailing and never had to do any work on any boat i've dived head first into the unknown. Now this thing is in really good shape and sitting on a hard stand (4 acro props and keel sitting on the ground) in having said that, the bottom of the keel has a bit of damage to it right on the bottom but it's been repaired before and there are 2 cracks along part way just a bit past where the keel becomes boat belly. The inside of the hull where the cracks are is filled with cement so i'm guessing the cracks don't go all the way through but i will be chipping some out and filling with epoxy before antifouling and painting. Perhaps i should mention i'm taking the entire boat back to cement

Question time-

1- what epoxy would be best to use for repairs?
2- do i need to etch the cement before i paint it?
3- should i use epoxy or cement to repair the keel?
4- how many coats of undercoat and antifoul and what is the best to use for ferro?

I will post photos of the cracks at a slightly later date (haven't taken any yet, was going to wait till i got it fully stripped)

[atoll]

cracks are generally a sign that the steel core is rusting and has expanded,and will continue to expand no matter what you do in the future,leading to total failure of the hull as water seeps in.

epoxy with micro balloons,collodial silica and cotton flox are light enough so it does not sag out from repairs on the underside of the hull.

but it might be a good time to evaluate if you want to spend money on something that may be an ongoing problem.

[Wogboy]

It kinda looks like it's only cracked down to the first layer of chicken wire but i'll know more tomorrow, going to chip away some concrete along the crack. In having said that, the crack itself isn't very long. Thanks for the advice. Every little bit helps

[Steve Bean]

I am the owner since 1985 of a Samson C-Mist 32 ferrocement double-ender. My first advice is to get a copy of Colin Brookes' book, "Ferrocement Boats." It's the best book I've seen on the subject and the most recent . He describes an epoxy mortar for relatively small repairs: epoxy glue, cement powder, and sand. It cures in a few hours. Repairs I used it on six years ago are sound. To chip out around cracks and rusty spots I use an air hammer I got for $10.00 at Harbor Freight. Of course you need compressed air to drive it. Is your crack associated with any sign of rust, such as visible rust stains? Do not sandblast the boat. It accentuates small superficial cracks that are insignificant. When you chip away at the crack, follow it all the way to the end or any rust. Think like a dentist working on a decaying tooth Get all of the decay, not just most of it. Get the book. Get the book.

[Wogboy]

Originally Posted by Steve Bean

I am the owner since 1985 of a Samson C-Mist 32 ferrocement double-ender. My first advice is to get a copy of Colin Brookes' book, "Ferrocement Boats." It's the best book I've seen on the subject and the most recent . He describes an epoxy mortar for relatively small repairs: epoxy glue, cement powder, and sand. It cures in a few hours. Repairs I used it on six years ago are sound. To chip out around cracks and rusty spots I use an air hammer I got for $10.00 at Harbor Freight. Of course you need compressed air to drive it. Do not sandblast the boat. It accentuates small superficial cracks that are insignificant. Get the book. Get the book.

Already looking for it. Thanks a heap!

[Wogboy]

Ordered the book! Thanks again!

[Steve Bean]

I'm happy to add more, but right now I'm focusing on finishing up my own small repairs and bottom treatment to get my boat back in the water this week. I'm glad you found a source for the book. I'm sure you'll find it encouraging.

[atoll]

Originally Posted by Wogboy

It kinda looks like it's only cracked down to the first layer of chicken wire but i'll know more tomorrow, going to chip away some concrete along the crack. In having said that, the crack itself isn't very long. Thanks for the advice. Every little bit helps

good advice from steve bean.
generally along the bow forefoot/stem keel area the cement layup is pretty thick,though it is important to try to remove any rust,then seal as best as possible to prevent air and water seeping in to the core.

water generally moves sideways through the core in ferro boats rather than directly through to the other side,resulting in areas effected leeching rust and eventually popping off or cracking.

i had a similar problem all the way up along the stem which required re filling regularly,that being said i believe the boat is still afloat and in use 8 years later.
regular coats of cheap gloss house paint every year hid the rust streak up the bow

[NevilleCat]

If you haven't followed them on YouTube the guys on Catalpa use "Megapoxy"
Megapoxy (Epoxy Resin)

https://www.youtube.com/watch?v=aFwNPbN8o6w

https://www.youtube.com/watch?v=2Jxuj73gZkI&t=79s

https://www.youtube.com/watch?v=MwE9VRGUwkI