Ferro Cement Hulls ?

[jim lee]

Kai Nui,

Naw, I wasn't putting "The Cement Ship" at Capatola into my list. I figured that one was kinda' a special case and didn't count.



"The story of the S.S. Palo Alto begins on May 29, 1919, when the newly completed, 435 ft concrete ship Palo Alto slid from dry dock into the San Francisco Bay" Was the Palo Alto the first cement ship? (Its the one in Capitola. And I don't think its going to last another hundred years, its fallin' all to bits.)




Were the boats on the Half Moon Bay beach Ferro? I can't be positive. I was just a kid, someone told me they were. Never thought to doubt it. I know one was wooden, 'cause where the wood was missing you could see throught to the inside where the familly were living. Ma, Dad n' the kiddies.

Funny how some scenes stay with you.

-jim lee

[roverhi]

How do you get cement to stick to cement. Doesn't work worth a damn patching a sidewalk, hope it works better on an FC boat.

If you have compression damage on a steel hull, you cut out the damage weld in a new piece. In an FRP hull, you cut out the damage and laminate up a new section with the new resin bonding to the old. Suppose you could bust out the old concrete and do the same with Ferro. The old armature would have to remain intact or you would lose the strength which is really in the steel, not the cement. You also have the bond problem with new and old cement. Seems like the only way to patch a ferro hull is with an Epoxy laminate. You still have the problem of stabilizing the armature in that case, however. Can't see that patching ferro is 'easy.'

If you want a quick, actually not so, and dirty boat, cement will work. Especially if you are talking backyard construction. If you are looking at a sailboat as a place not to have all your money sink, then it is a poor material. People are just not willing to pay for the cost of quality ferro boat. Having built a boat from a bare hull, can tell you that less than a quarter of the cost of a sailboat is in the hull. A shame to piss all that money away on a ferro hull.

We built our boat in a Ferro boatyard. A great herd of 40'+ Sampson designs. Most were begun in a messianic trance by disciples of Sampson who had bought the hype. By the time we got there, most of the original owners had lost their faith and givren away their sweat equity for pennies on the dollar. Some of the hulls were on their 3rd or more owner in less than 10 years.

None of the hulls were schlock projects. All the armatures were made to rigid design specifications, plastered by experienced professionals, and each stage inspected and attested to by a reputable marine surveyor. Even with all that care, 50' hulls were selling for way less than half what a Westsail 32 bare hull was going for.

We were in the yard for a year, finished our boat and went sailing. We stopped by ten years later and nearly all the hulls were still there. Believe out of 15 or so relics, only two had been launched in nearly 20 years. It was a field of dreams for which the players never showed up. That really isn't the fault of the strength or integrity of the hulls but speaks to the value.

As far as crazing, small cracks, of ferro hulls, it seems to be inherent in the concrete. All the boats in this yard had some crazing. Don't believe it's structurally significant unless it allows salt water to penetrate to the armature and rust it to oblivian. Most of the owners were resigned to putting a thin skin of epoxy on the hulls to seal the concrete.

As far as ultimate structural strength, I'm sceptical. Have seen one and personally know of another ferro hull that didn't have much impact strength. You are telling me all the other ferro sinkings are the result of insurance fraud not structural problems. Maybe yes, maybe no but in any case it is a big red warning flag for a purchaser.

So if you are looking for a deal and find a quality ferro boat, buy it real cheap. Then hope someone is at the other end when you try and sell it.

Aloha
Peter O.

[Steve Kidson]

Nothing like the subject of a ferro hull discussion to polarise the punters.

I will raise my colours and declare myself a ferro boat owner, and prior to purchase, did quite a bit of research into the material. In summary, I was convinced that for what I wanted in a boat, and the budget I had to spend, ferro was an acceptable option that would give the "biggest boat for the least money". My boat was purchased needing fitout, but I own a cabinet making business, and the boat is on the hard in our factory yard undergoing such works.

I can agree that there are some apalling examples of ferro hulls, and it is these that have given the medium a less than favourable reception. Mine is a Hartley 32, professionally built in 1980, and was in the water for some 23 years before I pulled her out to re-fit. I have no rust, no swelling of armature (indicating rust), and when re-painted with a 2 pack finish, she looks like a glass boat.

And for all the knockers who associate ferro boat = slow boat, during the 1970's a ferro boat called Helsal cleaned up most of the offshore yacht races down here in the South Pacific, including the Sydney - Hobart.

For me, I want a boat to cruise in, relax and spend time on the water in. I am not concerned with being the fastest, I do want to be comfortable and enjoy myself. The hoards of anti-ferro people who, through much negative press have driven down the cost of such boats have done me (and probably many others) a great favour as it has enabled us to purchase more boat than we might otherwise have been able to!!

Fair winds

Steve

Jim Lee, you are correct. The past couple of years have been really hard on the Capitola boat. Several big storms have taken their toll. There are 2 FC hulls that I know of in Half Moon, and yes, they are questionable, but neither is complete.
I stand by my earlier statements that all mediums have their good and bad points. IMHO the problems with FC boats tend to be terminal as compared with comparable damage to a fiberglass or steel boat. Not to say that the FC boats are more likely to fail, but if they do, the low value makes them a better candidate for a reef than for a restoration project. A FC hull properly built, and contantly maintained should give a good lifespan, and perfectly acceptable service. I also agree that ferro boats can be relatively fast. Allot of the Sampson designs are rolly, but that is in the design, not the material. I have seen fiberglass boats that were not as fair as many of the FC boats. Again, this goes back to the talent of the builder, not the material. FWIW the boat that I did not get brings up another point I have made before, that is the feel of the boat. A good boat feels right, and a boat that does not feel right is not a good boat. That boat felt right, and the current owner is very happy with it.

[Alan Wheeler]

KainNui, you have made some good points, but one or two I just have to address.
(snip)"the problems with FC tend to be terminal". I just have to say, simply NOT TRUE. I see comments like this often, but repairs to FC are easy, cheap and long lasting.
(Snip) "and constantly maintained should give a good life span". Once again, NOT TRUE. FC requires little maintanance if any at all. I know of one that the owner doesn't even anti-foul. It just gets a good clean every year.

Yes you are correct in that speed, handling and motion is to do with design, not what the boat is made from.

So how long has that big ship hull been up on the beach?? I wonder what other material would take the pounding she must have over the years and still remain as intacked as she looks.

Well, I guess it is dependant on the skills you have. I would not take on the project of replacing rusted out reinforcement on a FC boat, so I would have to pay someone. This wold rapidly excede the 15000-25000 it would cost to replace the boat.
As for maintenance, I realize the hulls do better than many other materials without regular haulouts, but things like topside paint are necessary to keep the hull sealed. The small scrapes we all get whie sailing can open the cement up to pinholes, and eventually rust. For maintenance, I am talking apples for apples. Quite often a GRP hull can handle just being scrubbed once a year as well. Any boat, even FC will be more likely to develope problems if neglected.
The ship has been on the beach since the 30's or 40's. It was originally planned to be a restarant. The photo that Jim Lee posted looks to be several years old. 2 years ago we had some heavy storms that did quite a bit more damage to the boat.
And if I did not say it before, great pics Jim Lee!

[Jeff H]

For what it is worth, in a study of long term maintenance costs that was performed by Boatbuilder Magazine some years ago, the results showed that Ferrocement was one of the most expensive materials to maintain. It came in right ahead of Steel which was found to be the highest maintenance material and conventional wooden boats which were also at the high end of the scale. Aluminum and then fiberglass came next with cold molded construction coming in best of all.

Jeff

[Alan Wheeler]

Firstly, don't take me wrong here guy's, I am not arguing with any "tone". I just think there is so much negative trip out there about FC and it's time to start stating some facts from personall experiance.

Jeff...What's to maintain???? I have not had one issue with my boat hull in the two years I have owned it. Neither did the previouse owner scince it's it was launched in 97.
I know of many hulls that are much older than mine with exactly the same experiance. No Maintanace except the normal paint jobs. One, a 50ft Tahitian, is from the early 60's.

Kai Nui... It is most unlikely that the inner armature will rust. By the very chemical nature of the Cement, stops this from happining. When you do see rust streaks, it is NOT the inner armature, It is small strands of chicken mesh that have been too close to the surface of the plaster.
Scraps NO NOT make the material porouse. Cement is the same all the way through. The surface is no different to the inner core of it. I had chipped a hunk of plaster away from the bow due to someone not telling me the anchor was still touching the water as I made my way forward. The big heavy anchor swung off a wave and the point nailed the bow chipping the cement. It was a year before I could make the repair and I had and still have no problem with rust. The repair was simple and you can not see any sign of a problem another year on.

[Wynand]

Not all boats are built equal, regardless of materials used. Show me a bad builder and I'll show you a poor boat, again, regardless of material used.

Nevertheless, all boats needs preventative maintenance and repairs to keep it in mint condition. And herein lies the dilemma, some materials shows lack of maintenace worse than others. Metal will rust, perhaps ferro as well and unfortunately, this scenario is a very visible malady.
OTOH, a fibreglass with blisters, seepage or delamination problems will not attract any attention as this is not very visible apart from close inspections and haulouts....Same can be said of wood construction.

Different people have different budgets, needs etc. FerroCement is the answer to many people who believe in its merits, just as others who swears by some different materials.

In the end it all boils down to personal preferences.

[Alan Wheeler]

Yep I agree Wynand. I certainly ain't trying to say FC is better than other materials, It's IMO that it is given a bum rap based on something that doesn't exist anymore.
Perhaps if I come at a different angle.
The hulls still around that come from that era, that have issues, are no longer in "sailing" use. They tend to be lying around looking digraceful and giving the overall fleet of FC a bad name.
99.9% of all negative replies come from people that speak second hand. As in repairing or cracks or what have you. Or, they speak of these old junks no longer in use
I have yet to meet or read of an FC owner, that has a boat today, that is having issues. Maybe one or two exist, but I have not found any. Infact quite the contrary, all I have meet or read of, are in praise of their boats.

[roverhi]

New concrete does not like to stick to old concrete. In fact not much likes to stick to cured concrete. How do you make a patch on a boats that's been holed. I keep hearing it's easy. Still waiting for someone to tell us how.

For a boat with a crushed/holed section, how do you maintain the strength of the armature. The strength is in that steel and it aint' very stiff if nothing is holding it rigidly in place. That's the job of the concrete but if the concrete is busted up, the steel will flex reducting strength way more just in the area of damage.

Aloha
Peter O.

[Alan Wheeler]

Good question Peter. Firstly, it's not concrete. Not like the concrete you pour as a path or building structure that is. This is a special plaster mix with a very high concentration of cement and additives. New will bond to old, providing the old is well prepared and very clean.
If the Hull has been damaged due to an impact, the repair maybe as simple as knocking out all the plaster till all damaged areas have been removed. Then the armature pushed back into position and a new mix of plaster applied. If the armature has to be replaced, it is a case of knocking back the plaster past the damaged steel work and then a new segment welded in. Then once again a new batch of plaster.
I haven't carried out such a job myself yet, and I hope I never have to, but I personaly now a guy that has done this many times. He has personally built 37 FC hulls and repaired several for people. If I see him, I will ask what he does and try an provide a more detailed and accurate explanation of the process.

[Jeff H]

A couple quick points here:

In the U.S., the term 'Concrete' is used to define a mixture of portland cement and one or more aggregates. So Roverhi is correct in using the term if he is in the States, but as Wheels points out it is not the your normal concrete. Ferrocement boats generally use a very low slump 'high-early' portland and with a very carefully sized sand aggregate.

I think that Roverhi's point is quite valid though. It is extremely difficult to get a secondary bond with cement. The diffiulty in getting a secondary bond between even 'green ' cured cement and frresh cement is prime reason that a properly built ferrocement boat must be laid up all at one time.

In one of the earlier discussions on this Forum someone had posted a link to a website that had a technical paper on the strength of secondary bonds in ferrocement. There was a very significant decrease in strength across the cold joint. To the point that the author discouraged repairs of ferrocement with portland cement. The recommendation was to use a reinforced epoxy/fiberglass to make the repair with a larger contact area (taper) than would be normal in a fiberglass repair.

Respectfully,
Jeff

Essentailly a FC hull is made out of the same stuff they side homes with here in the western US. I have worked several insurance claims that required patching the plaster. The more reputable contractors will not do a patch do to the possibility of cosmetic failure. This has always made me skeptical about repairing a FC hull, but I do not claim to be an expert on the subject. I have noticed that FC hulls seem to have a better record in Kiwi land, and I am wondering if the materials are chemicaly different than the Portland cement used here in the US. I realize that personal taste is regionally effected, but there has to be something more here, as the Kiwi boats really do sound of better quality.

[Alan Wheeler]

I am going to post a couple of pictures in the gallery of some FC boats in my Marina, just for interest sake of what they look like.
Also just of interest, as I understand, the mix ratio of cememt to sand is 2:1/40MPA. It can also have Pozzalan added to improve water resistance, but it is not a "have to use" product and doesn't get used much at all now.
Portland cement is not the only cement that can be used. In fact, it is not actually recommended anymore.
It is recommended that a Sulfate resistant cement be used.

Take a look at the internal steel work of an FC hull. You will get an idea of why these things are so strong. As I said before, it's NOT the cement that gives the strength.http://www.ferrocementmethods.org/2.html