Ferro-cement hull repair

LeBaron

Recruit
Joined
Jul 1, 2017
Messages
1
I am new here and just got my first ferro-cement boat. (36' Samson c she'll sailboat)
It has a few spots on the hull below water line mainly around the keel that are going to require repair. I've been reading up on different methods and opinions and was hoping to get some more opinions . This is my first repair on a ferrocement boat so I'd like as much info as possible before I patch her up.
The damage is not deep and no holes. Only one spot is leaking slightly. And in one place you can see a very small amount of the chicken wire.
Thoughts?
 

minuteman62-64

Lieutenant
Joined
Apr 12, 2011
Messages
1,350
Some sort of thickened epoxy?

​I haven't thought about ferro-cement boats since the 1970's, when I was dreaming of building one. Probably good I didn't. A guy in my neighborhood did and the unfinished hull sat in has back yard for about 30 years - until his widow had a crew come in and demo it and haul away the residue :(
 

southkogs

Moderator
Staff member
Joined
Jul 7, 2010
Messages
14,783
LeBaron Welcome aboard:

I moved ya' to the restoration forums to see if we get a few more peeks at your question.
 

Ned L

Commander
Joined
Sep 17, 2008
Messages
2,266
Yep, as mentioned above, .... haven't thought about ferro-cement in decades. A good construction method if done correctly. Considering the technology hasn't changed since it was in vogue I would use the repair techniques that were written about then. As I remember, basically chip away - jackhammer if needed- any suspect concrete, chip back into clean chicken wire, cut out any rusted & damaged mesh, tie in new patches of harware cloth, chicken wire, etc and plaster in new concrete. (I would stay away from epoxy as the two may not bond homogeneously.)
I am curious, you say the "damage is not deep and no holes", but it is leaking. What is the type of damage that is allowing for leaking, that would seem to indicate some sort of damage that is full thickness.
 

Cdubb2010

Petty Officer 3rd Class
Joined
Apr 22, 2014
Messages
79
Never actually worked with the stuff but have done a ton of homework on them, love the material, so maybe I can help out. From what I've gathered Ned is pretty spot on. Identify the trouble areas and start breaking out the FC in the sounding areas and examine the wire below, rust means it has to go. Now go in all directions around the damage doing this till you find no more rusty wire then go a little more to apply new mesh or chicken wire to uncompromised existing mesh. Be sure it's the right mesh you are using as a patch, the print I have for a Hartley Norsk 40 calls for galvanized but I think this may be antiquated nowadays. I would also suggest knocking out the FC from the inside as well around a repair site if you have access, this would lower the risk of air pockets caught in the hull, which leads to rapid failure. Biggest thing I can say get the FC mixture and consistency right, too thick or too thin it's doomed to fail, gotta find that Goldy Locks zone. I was suggest reaching out to Colin Archer on this at Hartley. Sampson and Hartley boats are now one in the same, plans come from the same catalog now. Archer is kind of the go to guy in the FC world and is very helpful, I've spoken too him some in regards to my own FC desires and he is happy to help and awnser questions newbies have. This is the guy to ask about the mix and any grey areas of the repair you may have. YouTube also has one video I know of that shows the process on tape. Best of luck and just know I am very much jealous of your concrete boat!
 
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