SailNet Community

SailNet Community (
-   Boat Review and Purchase Forum (
-   -   Ferro cement (

dshearn 06-27-2004 03:51 PM

Ferro cement
there is a boat for sale in our harbor made of ferro cement. I have never heard of it before and was hopeing some one on here might be able to give me some insight in to its long term surviability.

Jeff_H 06-27-2004 06:25 PM

Ferro cement
(This is from a previous discussion of Ferrocement)

My take on ferro-cement is that it is, in fact, pound for pound the weakest of all of the commonly used boat building materials. Ferro-cement operates by the same principle as fiberglass, in other words, a high tensile strength reinforcing held by a high compressive strength, low tensile strength cement. The cement in ferro-cement ideally is a high strength Portland cement. The cement in fiberglass is polyester, vinylester or epoxy resin. The tensile reinforcing material in ferro-cement is steel (sometimes with glass fiber, and in fiberglass its glass in a variety of forms, kevlar, carbon and all kinds of new variations on these materials.

Ferro-cement''s weight comes from a number of sources. First of all, no matter how small the boat, there is a practical limit to how thin ferro-cement can be. Ferro-cement needs to have a minimum thickness in order to have sufficient depth of material to protect the reinforcement from moisture. Because of this boats below 40 to 45 feet are generally considered too small to use ferro-cement efficiently. (i.e. they weigh more than they would in some other material.)

The implication of the weight issue is not readily obvious. At the risk of sounding like a broken record, Weight in and of itself does nothing good for a boat. It does not make it stronger, or more comfortable or more stabile. Weight does increase the stress on the various parts of a boat. It increases the size of a sail plan required to achieve a particular speed. It increases drag and typically means that for a given draft a boat will have a less efficient keel (i.e trading off greater drag for the same amount of leeway.)

In order to carry more sail area the boat needs greater form stability, which comes at the price or a choppier motion and greater drag, or greater ballast or deeper ballast which adds more weight and drag and perhaps depth.

To keep the weight down, many ferro-cement cement boats have reduced ballast ratios when compared to other construction techniques. This means that they need more sail area because of their weight but they can''t carry more sail area because of reduced ballast ratios without using lower aspect rigs which are by their very nature less efficient.

This is further complicated by the fact a higher proportion of the weight in a ferro-cement boat is carried in the in the topsides (and sometimes decks). This means a high center of gravity which has a variety of implications; reduced stability, wider roll angles, smaller angles of ultimate stability, and more prone to excitation rolling (which may be slightly offset by the greater inertial moments due to weight).

Then there is maintenance costs. In a study performed some years back looking at the life costs of various materials, ferro-cement-cement came out as the highest maintenance cost material (if I remember worst to best was ferro-cement, steel, conventional wood, aluminum, fiberglass, cold molded wood) Of course as with any generalized study there will be case by case exceptions and given the comparatively small sampling of non-FRP boats it can be easily skewed by a few bad apples.

Other problems with ferro-cement are the difficulty of connecting things to it, and prevention of rot in wood in contact with ferro-cement. The difficulty in bolting to ferro-cement is that ferro-cement hates localized loadings. It’s hard to glue things to ferro-cement. secondary bonds are greatly weaker than primary bonds.

Then there is the market value thing. ferro-cement does have a reputation in the States that does not match the comparatively high regard that it is held in other countries. Some of this is just plain unfair prejudice but some of this comes from real shortcomings in the materials as noted above. A well-built ferro-cement boat can be a good cruising boat. But the image of the crudely finished ‘hippie’ built cement and rust buckets still clouds the perception of ferro-cement for many North Americans.

The other problem is telling whether the boat that you are looking at is a good boat. It is very hard to do non- destructive survey techniques to tell whether the original work was done well and is in good condition. While sounding will reveal any major separations in the cement to reinforcing bond, it does little to determine the affects of fatigue, poor curing practices or cold joints. With Ferro-cement it is particularly important to maintain the ferro-cement parts in good condtion. That can be very significant. People who buy boats because they are priced well below the market, often are overly frugal or just plain do not have the money that it takes to properly maintain a boat. Anotherwise good Ferro-cement boat left to poor maintenance and miss-handling can quickly become a poster child for why North American’s don’t trust Ferro-cement

To me the real cost of owning a boat is the difference between what you paid for the boat, the cost of upgrades and maintenance and the price that you can get when you sell the boat. The problem with a lot of low value boats is that the sales price is always limited no matter how much you put into the boat. This too works against ferro cement boats.

I guess my conclusion is if you are strictly looking for an initial up front cost boat and don''t mind putting some sweat equity in, and you can look past the sailing shortcomings, and you actually find one that was well built and well maintained, a ferro-cement boat might work out fine for you. For most of us, they do not.



dshearn 06-27-2004 06:38 PM

Ferro cement
Thanks Jeff for your imput. That explains alot.Looks like the price on the boat is low for a reason .

Sasha_V 06-27-2004 06:42 PM

Ferro cement
This topic is going to attract a few opinions (what in yachting doesn''t) so I will throw in my 2c worth (adjusted for currency conversion and inflation + GST).

Cement boats have exactly ONE virtue to offer. They are cheap. Cheaper to build then either GRP or cold molded timber or alloy.
Of course int he modern world, the hull is only one part of the overall investment that equals "yacht"...and that means that quite frequently, cement boats represent a dollar value that can never be recouped. Because the spars, blocks, sails, electrics, electronics, winches, engine, etc etc etc are just like those found on a "real" boat...only bolted to a hull that a majority of sailing folks will never trust beyond staying afloat at the dock.

Cement boats suffer from a couple fo issues that give them a bad rep (some of which may not be justified). Many of these boats were "home built" as there was a huge fad for them soem years ago. Quality control is thus a bit...errr...patchy, at beast. They have lumps and bumps and irregular thickness in the hull. The mix is variable, so some areas are more brittle then others (and cement boats are ALL more brittle then GRP or wood).

Some mixes of cement are not as water proof as they ought to be and suffer capillery leeching. A lovely state in which you are living on board a seive nd trying to throw the water back overboard faster then it comes in. your major ally in this battle is PAINT. If this thought comforts you, then go for it.

Also linked to the above point is the reinforcment of the cement. It is chickenwire.
This means that in a grounding, and inpacts or whatever, lots of little concrete hexagons fly from your hull, and leave behind chickenwire to hold back the sea.
My favourite worst case scenario though, comes form the possibility of lightning strike! Imagine all of the chicken wire reinforcing suddenly going incandescently hot and blowing off the cement that surrounds it. Up the creek without a paddle does not begin to describe the situation!

So what are cement boats good for...well, you can buy a 40 foot cement boat for the same price as a 26foot GRP boat an use it as a live-aboard in oone of the nicest marinas you want to live in and that is it. Your "floating" concrete apartment by the water. Just don''t try sailing it too much or in too hard a weather.

Oh yeah, cement is kind of heavy you will have a boat that weighs about the same as a steel hull...but with absolutely none of the advantages. (even your compass will have devation issues like a steel boat, because of the mesh in the hull).

Anyway...that is my opinion on the matter. I am more then sure that there will be cement boat officianados along any moment to defend their point of view.


dshearn 06-27-2004 06:52 PM

Ferro cement
Thank you for your response Sasha.Haveing never heard of Ferro before i was intrested in this boat. Obviously i am much less intrested now. Well Sasha i am really intrested to see how a cement Officiados deflect waht you and jeff had said.

thorJ30 06-28-2004 03:49 PM

Ferro cement
No cement boat afficionados coming to voice their point of view ???

All the points above are of course right. There are actually a few boats mainly built in Holland which are quite nice. Still even in EUrope where people know about their excellent built quality much cheaper as well.

Also, because of their usually low budget restraints, most ferro boats have helplessly undersized components. Now if you add a couple of real big selftailing winches, a couple of other correct sized accessories, your good deal becomes vain in a hurry ..


dshearn 06-29-2004 12:13 AM

Ferro cement
i allready own a 33 cal i am prefectly happy with that has some surprisling good speed to it. But i was kinda shocked when this big old 50 footboat was priced what i consider pretty darn low. I am pretty close to makeing a liveabord for finacial reasons , so i just assumed that this 50 footer would be a great boat to do it on. Corse that was last week and i knew nothing about Ferrocement boats. This one looks like a production boat not something some one made in there back yard. But who wants to make that kind of purchase when there is ZERO upside to it. Even assumeing i lived on it for the next 30 years untill i retire i would still more likely then not have to buy a diffrent boat if i wanted to go cruseing. Soooo i just dont see it happening now unless he wanted to give it to me for the price of its engine :)

ISLANDCHIEF60 07-10-2004 02:39 PM

Ferro cement
Well dshearn, I have to dis agree with some of what jeff and sasha have to say. I for one live and sail on a Ferro-Cement boat. I love my boat. However I have one that was built correctly. Mine is a Stan Huntingford Mapel leaf 60. There were two of these models built. The sister ship is in St. Tohmas called New Horizons and is chartered. I`m in the northwest and cruise the area also the boat has also been in the Trans-Pac race taking third in its class. Not bad for a Rock. Its a shoal draft with a drop center board. The boat is also as fare as any fiberglass boat thats poped out of a mold. As far as maintenance goes. I don`t have the blister problems that glass boats have or rot issues that wood boats have nor corrosion problems that steal boats have. Weight?? It comes in at 58,000lbs (dry). No more than any other 60ftr. Speed?? Well it will sail 10 kts with moderate wind all day long and has been logged @ 18 kts in heavy weather with reasonable comfort down below. I`ve never had the bobbing effect that was described. On one outing I was with two other boat boats, a 58ftr and a 63ftr and they didn`t fare that well when the winds started to kick up. I also had to reduce more sail than normal for them to stay close. So the point of all this? It dosen`t matter what the boat is made of as long as its built well. There is a web site that will give you tons of info on Ferro Boat " The World Of Ferro-Cement Boats". Don`t loose interest on a Ferro-Cement boats. It true that they are less money. However you will pay good money for one thats built right. Don`t let these guys fool you into thinking that all Ferro-Cement boats are trash. Every type of construction has boats that are built well and poorly. They key to it all is education on your part. If you know what to look for, you can get one of the best boats around. Ferro_Cement boats have been around for quite some time. As a matter of fact. In New Zealand, Austrailia and in Europe they are still building them. So They way I see it if they are still in construction then they can`t be as bad as what is led to believe. The biggest problem with this type of boat wasn`t the boat itself it was the builder and marketing. The salesmen tells Joe Shmoe that he can build this nice boat in his back yard with ease. Joe says great and soon discovers its not easy at all and gets fustrated with the results. Soon starts the bad mouthing and it snowballs from there. If you find a properly built Ferro-Cement boat and you don`t plan on re selling any time soon then I would stongly consider it. I`m taking mine around the world and I feel perfectly safe in it. I don`t woory about logs or shipping containers or even whales. My boat was built with intergrated tanks with removeable deck lids. So in the event I was ever holed then all I would loose is some fresh water. It also has a colision bulkhead. The boat was truely design with the ocean in mind. If I sound like I`m proud of my boat, I am! However if I had an equaly built boat in any other construction I still would be. I think I found a dimond in the ruff. Ruff being Media Histeria. There is nothing wrong with having a Ferro-Cement boat. The trick is finding a good one. I would also look over seas for one. Good luck with you search.

Jeff_H 07-10-2004 07:31 PM

Ferro cement
There is a huge difference in the relative weight issue between ferro-cement and otehr materials when you are talking about a 60 foot boat vs a 50 or smaller footer. Properly built, ferro cement is a perfectly reasonable material for a 60 or so footer. It still is a comparatively expensive material to maintain over its life cycle if maintained on an equivillent basis to the more common boat building materials.

Just for the record, while blistering does occur in fiberglass boats built during a narrow period of time, it is not a universal problem within the better built boats of the recent past.

By the way, what year did your boat take a third in the Transpac and how many boats were in its class?


dshearn 07-11-2004 11:43 AM

Ferro cement
Thanks for the info ISLANDCHIEF. I have kinda moved away from the FC boats for a couple of reasons. It seems you can buy a bad boat made of anything. the Survyers in my area have little knowledge of FC ..... sure they will do them but they tend to blink funny any get all nondiscript when pressed on differnt points. It seems to come down to there same testing for fiberglass. I myself am quite new to boating and rely greatly on word of mouth and name brand recognition. And or course I am way to ignorant on teh subject of FC. I am also starting to look more at racer/crusieing boats. SO for a number or reasons i am moveing away from the FC boats. But i do appricate your time and thank you for responding.

All times are GMT -4. The time now is 03:21 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome