Ferrocement Corrosion

I have a Samson design ferrocment boat that I am working on for an organization called Youth With a Mission Ships. Hull was laid in '72, sat in Michigan for many years and then was finally put in the water 2.5 years ago in California. When we hauled out a few weeks ago I found that the boat had a lot of blisters that had rusty water behind them and lots of delamination back down to the ferrocement, roughly 85 square feet. I found lots of wet spots along the keel. From waterline at the bow all the way to the aft end of the keel I have found pockets of water with black, rusty, crumbly cement around the rebar. I can take a chisel and put it through the cement like a nail in a piece of wood. Also the water tanks were not properly seeled so water has been leaking from the inside out the tanks into the side bilges. When I filled the tanks it leaked out through the hull to the exterior through a C-shaped crack about 20inches in height. I started to chip away at the top of the C and you can tell there are open spaces that appear to go back and up. Lastly in the aft bilge I found a crack in the bottom and in one area there appears to be black around a hole. Is it possible or even advisable to fix these issues?

 

If water is penetrating the hull after 2.5 years the entire structure is suspect and likely was not built well. My very well built ferro-cement boat shoes zero signs of water ingress after 40 years in the water and could be hit with a sledge hammer without damage.

I would strongly suggest walking away from the boat, even if repaired it will likely cost many times what it is worth to get the boat sorted. Ferro boats have almost no value these days. Will be less costly to go find a boat that is in good condition and ready to go.

There are also all the regulatory issues if you plan to have groups of kids aboard. You need something that can get coast guard certified for passengers unless you stay under six passengers.

 

Pretty much it is shot. The water and salt will keep on corroding the metal mesh and rebar inside. If there is water leaking to the extent you say, the structural strength is compromised and the boat is not safe.

 

That hull is history. Scrap it now before you waste a huge amount of time & effort on it. There are a lot of boats out there, this one was never meant to sail.

PDW

 

You can't operate it legally in the US as an organization even if you did fix it. The USCG wont even look at a ferrocement boat, and you need their approval. Haul it to the dump.

 

Because this boat was never launched when built there is a good chance the builder knew he had not plastered the hull properly and gave up on it. If it was done right it would still be like new.

 

Thanks for all the input ... Leadership is not ready to give up and is looking to do an X-Ray on the hull .. does anyone know anything about who to contact or how much it may cost.

 

By your description the boat is junk, no way it's going to get passenger certified with issues like that. X-Rays will just be an expensive way to confirm it.

Anyone done a stability study on the design yet to see if it would meet standards even if the hull was good? Talked to the coastguard about if it is even possible to get a COI for a cement boat?

There are ways around the rules ( carrying less than six passengers, calling them "trainees" or "crew"), But to use these loopholes to carry young people offshore in an inadequate boat would be extremely reckless.

Sounds like leadership needs to hire someone who knows sail training vessels if they are serious about the program.

 

Has the boat had a proper marine survey?

 

It was planned to be used outside the states. It is of my opinion that the boat be scrapped and I have no plans on moving forward with the project. However I do have an obligation to answer the questions the leadership asks and try to back my opinion up with others as well.

 

They might be able to dodge the legality of operating an inadequate boat with young people aboard, but not the morality of such a choice. I see they are already running another boat, but couldn't find anything on the web site about certifications. Hopefully they have done the needed stability and safety work on that boat.

Good choice running away form this project, you don't want your name involved if something goes wrong. Probably worth putting your findings in writing.

Any local surveyor should be able to confirm what you are telling them without the need for x-rays. With a hull in that bad of shape x-rays will be an expensive way of confirming the obvious.

If you need someone else to talk to about this my father is a surveyor up in San Francisco who spent many years running tall ships with students aboard. I am sure he would be happy to talk to you if you called him. Steve Wedlock of Whiting and Wedlock Marine Surveys.

 

Xray will be a good indication of the internal armature, but not the "bee's knees". Given what you've described, I think the xrays aren't necessary and a cheaper alternative is an assessment, by a qualified surveyor. I'm sure he'll say what you've read here and the backhoe can have it's way with her, but at least you'll have covered your bases. Lastly, most insurance companies will not touch a Ferro build in a passengers for hire situation, particularly one with this one's history. A highly documented build, by a well known and respected builder, yes, but not this one.

 

Thanks for the info

 

Good point, its almost impossible for me to get even basic liability for my well built, private use only Ferro-boat. I can't imagine how difficult it would be for a commercial boat

 

And I apologize if I sound a little hopped up about this, I am in the middle of reading "Tall Ships Down" and just read the USCG report on the Bounty sinking. So the possibility for disaster is at the front of my mind.

Would recommend both as very interesting reading.