View Full Version : Why Ferro Boats Have A Bad Reputation

30-11-06, 10:40
I know of one other poster in this forum who has a ferro boat. Wanting to catch up, I just did a search. However, it appears that CharlesM's last post was in May, and was titled, "Hurricane Holes in the Virgin Islands'.

30-11-06, 11:49
Do they? that's a new one on me? I would give serious consideration to one if I was in the market for a boat. I know that there are a lot of rough looking ones out there that have been somebodies project, who has perhaps run short of funds, or maybe been lacking in the necessary skills to do a proper job of them, but on the other hand I have also seen some crackers!

30-11-06, 11:50
Thank you very much for that. I have a few books on ferro-cement boatbuilding that I was about to try and sell, and here you are trying to destroy the market.

30-11-06, 12:00
Thank you very much for that. I have a few books on ferro-cement boatbuilding that I was about to try and sell, and here you are trying to destroy the market.

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Well I did try to inject a modicum of balance to the notion /forums/images/graemlins/confused.gif /forums/images/graemlins/smile.gif

30-11-06, 12:05
Twister. I'm looking for books on ferros. Do you have anything on maintainence? Scraping..painting...polishing?

30-11-06, 12:52
I think they are all concerned with building ferro boats, but I'll have a look. I could be very unkind and say there was no market for books on ferro-cement boat maintainence because, although plenty were started, not many boats were completed!

30-11-06, 13:00
They dont have a bad reputation, unless they crash into you...

30-11-06, 13:28
I have the following books for sale:-

"Practical Ferro-cement Boatbuilding" by Jay R. Benford. Publ: International Marine Publishing Co
"Cruising Boats - Sail & Power" by Jay R. Benford. Published by the author
"The Sailing Seventies - Ferro-cement Catalogue". Samson Marine Design Enterprises
"The Sailing Seventies - Designs, Engines, Chandlery. Rigging etc".Samson Marine Design Enterprises
"Fitting Out Ferro-cement Hulls" by Robert Tucker. Publisher: Adlard Coles

£5 each plus p&p or all five of them for £20 plus p&p

30-11-06, 13:36
there was no market for books on ferro-cement boat maintainence because, although plenty were started, not many boats were completed!

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I'd say not many on maintenance because .... what maintenance???? FC hulls are the ultimate in low maintenance!

30-11-06, 14:21
PM sent.

30-11-06, 19:00
Love the title, but too tired to make innuendos.

It is a fact that ferro gives fantastic value for money, I appreciate that there is no quality control on "home grown jobs", but there are craft out there with hulls built professionally that represent great value.

I used to have an old boat at Maldon and was near one fine ferro craft (can't remember if it was Ironestone?Lodestone?) I used to drool over it, then it sold, then a few weeks ago I saw it up for sale at a wickedly low price for what it represented.

Remember the pics at the time you got yours, lovely craft!

30-11-06, 20:13
I have had a ferro hartley for about 7-8 years now and in process of repairing hull and have done lots of rearch. Have found some new repair products which seem interesting but not used yet.

At the mo concentrating on my new steel for crusing and planing to repair hull of hartley to use as base in KZN while I cruse mynuyot in Indian Ocean over to OZ in a year or three.

Can swap notes if you like.

30-11-06, 22:21
If a ferro hull has been laid up incorectly, which is eassy to do if the ratios or mixing is not correct, the hull in this case is more or less suited as scrap. It is very difficult to detect for a purchaser or a survey the condition or the mix as it is mostly set in concrete so to speak. Some surveyors will not survey a ferro hull for fear of giving wrong advise. However a rule of thumb which some surveyors will go buy and others say is a load of hogwash, if the hull has survived in the water for 10 years and this can be proven, the chances are that it will continue to perform well for many years to come. Be more wary of a newer hull or a recently launched hull that has been sitting in someones back lawn for decades.

There is a cause for concern about the integrity of any ferro hull and this as well as many hulls being amatuer built is the main reason wether right or wrong as to why there is little demand in the second hand boat market hence the low price for second hand floating foot paths.

30-11-06, 23:11
iI don“t know if we are supposed to treat this seriously or not, but being bad at one-liners, like most forumites, I will try it.
Ferro cement boats have a bad rep for three reasons. These are mostly historic; that is , they used to be true, but may not still be true.
First. There is no easy way to establish the build quality of the armature after it has been plastered. Only a survey before plastering can do this.
Second. It was very common to start a project that was too big for the builders budget and ability. These were sometimes finished very badly, as the easiest way to recoup the investment was to finish it and sell it.
These are perhaps no longer valid reasons. It is about twenty years since ferro went out of fashion, and any boat built then that is still sailing, and perhaps has an Atlantic crossing or two on its CV, is probably not too bad
Third. It is easy to make a small repair in ferro, but to guarantee the integrity of a major repair is an act of faith. There are few boatyards who will undertake it, and insurance companies have been forced to write off hulls which would be repairable in other mediums, for the want of anyone who will“guarantee“the repair. This has led them to be unwilling to insure concrete boats. This is the only valid reason for the discount in their price.
If you want to go Blue water sailing, I would recommend ferro. It is hard to get insurance for blue water anyway, so it doesn“t matter if your boat is ferro, and as they are so cheap, if you sink one, you can just buy another!

30-11-06, 23:16
I love my ferro. Will be posting lots of current pictures as of December 24th.
Can't 20 tonne wait!

01-12-06, 13:55
I have a lot of pics of my hartley before and during the removal of the damage and cancer. Let me know and I can put some on my web site for you.

Also if you email me I can discuss how I intend to procees to repair amd repaint and what I intend to do to prevent the cancer occuring again

01-12-06, 14:00
I know nothing of Ferro...Cept to say when once tempted to buy a "shattered dream" Good Knowing friend said"You can tell if its bad when your foot goes through one day...Also on the subject of Floating concrete I can see from here a section of "Mulberry Harbour" thats been in and survived the waters from around D Day !944!! so well built and constucted I guess the Proofs in the Pudding...So to speak......

01-12-06, 15:41
There used to be a firm called Windboats Ltd, of Wroxham, Norfolk and they built ferro-cement boats. They used to exhibit at the Boat Show and were said to invite people to bash the f-c hulls with a hammer to show how strong they were. Their best looking offering was the Endurance class. Must be a lot still around if they were as well built as Windboats claimed.Anyone got one?

Properly constructed ferro-cement hulls would probably have been more popular if fibreglass hadn't come along.

01-12-06, 16:32
Concrete is massively strong in compression, but relatively weak on its own in tension. Hence the need for steel reinforcement.
This can be taken one step further for bridges and other 'simple' structures involving beams by pre-stressing the structure (ie putting a very high tensile load on the steel by attempting to 'stretch' it) before pouring the concrete around it. After the concrete has set, the tension on the steel is released, and the concrete beam is then effectively in compression.

This would be rather difficult to do for the hull of a yacht though...... hence why there is a complex net work of steel bars and mesh forming the shape and framework.
Although I am a great fan of ferro boats - I have sailed on a few, including a 19 tonne 39' ferro Colin Archer across Biscay, and in the Windies - I do have to admit that their resistance to concentrated impact loads appears to be relatively poor. Although one could argue that the same applies for all other materials apart from say steel and aluminium......
In the past few years, in the tail end of hurricanes here, various boats have either been washed ashore, or disappeared out to sea.
I know of a ferro boat and a single chine ply/epoxy boat (both around 37' LOA) that came ashore (in different years) on the same sandy beach (they did not have to bounce over rocks) after their moorings parted in Carlisle Bay. The sea conditions in both instances would have been similar. The plywood boat had a couple of small holes / fractures in the hull that were relatively easily repaired. The ferro boat had extensive cracks all over the starboard side of the hull (where she was pounding on the beach)and was subsequently written off - I think as much as possible of the interior was salvaged, and then the hull was literally broken up and taken away in a skip.

To anyone contemplating buying a ferro boat - they are very strong (usually!), can be very comfortable in a seaway, however like with all other boats they have their weaknesses along with their strengths.
I think it would be very difficult to justify building a new ferro cement yacht today - you might as well spend a bit more and build a steel yacht instead. Especially since the advent of modern CAD / CAM techniques where (eg) all the frames and shell plates for a steel boat can be cut out by a plasma cutter using data supplied by computer from the Design Office.
It is then 'just' a case of setting it all up, and welding the bits together!

01-12-06, 17:12
Ferro cement boats are crucially formed from two materials. Not a case of 'reinforcing the concrete'.

Cement (Not concrete, which contains agregate) is as you say excellent in compression.

Steel is excellent in tension.

It is the <u>combining</u> of these two materials that produces the hull. It is important to have a very high steel to cement ration in the finished hull - not 'just enough to hold it together'.

I agree, if you hit a Ferro boat hard enough it will shatter. But then it's a <u>simple</u> task to remove the shattered cement, reshape the steel work and replace the cement. Quite cheap to do, and will achieve an excellent result. Unlike a GRP boat that would have to be written off.

I suspect that the boat that was 'written off' as you mention was due to a lack of knowledge or time to effect a repair. As always, FC construction remains labour-intensive.

01-12-06, 18:16
Ooops, sorry about my wrong terminology!
Agreed totally that you do need a very high steel to cement ratio to give it strength - so much so, that if building new today, it is worthwhile investing in some more steel, and building the whole hull from steel one time.

The boat that was written off here after coming ashore had been well constructed in South Africa by a mason who 'knew his stuff' alright - she was a lovely boat. I had a survey job on her after she had been salvaged, and I was quite amazed / horrified at the beating she had taken. Yes, she probably could have been repaired, but it would have been a very big job - most of one side would have had to be renewed, and there were cracks on the opposite side as well.
In addition, the Owner / Builder didnt have the time or inclination to tackle this, after having spent 5 or 6 years building her 15 years before in South Africa. And even though she was virtually offered to anyone who would take her (for the salvage cost of the equipment), there were no takers.

Coincidentally, the single chine ply epoxy boat that came ashore on the same beach was also built in RSA - she is a 37' Robert Tucker design with a deep fin keel (bolted on) and a cantilevered spade rudder (no skeg). The rudder stock broke and she sustained a couple of holes in the hull, but other than that it was not an awful lot of work to get her back in commission again.

01-12-06, 18:56
When I restored my wooden boat in Totnes a few yrs ago there was a yacht hull that had been converted and was used for fishing under sail. When you rapped the hull with your knuckle it literally rang like a bell. She was concrete and just hearing the way the hull rang totally changed my opinion of this method of construction (if done properly). I think like others that the large number of poorly executed homebuilds has unfairly given them a bad reputation. Mike

01-12-06, 20:06
This has turned out to be a very interesting thread, which was my intention all along.
Thanks to all for the input.
I'll be taking close-up pics of my hull when I get there.


01-12-06, 23:58
hm, the concrete itself is not the structural material - it is the STEEL inside that gives the strength and the aim is to make a structure that is predominatly in compression. Now, under compression, steel is not bad - until a certain point where the steel kinks over. But surrounded by a bunch of concrete this point is delayed massively, and strength dramatically enhanced.

My personal view is that steel reinforced concrete (or more correctly concrete restrained steel mesh) is not an ideal choice of material for a boat - the potential strength is vast but then so is the weight. Steel or aluminium gives easily the strength needed such that the hull won't fail, together with better integration of bulkheads, less weight, and easier (visible and accessible) verification of hull condition.

02-12-06, 04:23
Yeah, but they cost more, too.

02-12-06, 07:46
I was sitting off a sandy beach on the south coast a few years ago when a ferro boat ran ashore (on purpose) and two guys set about beating a hole in the hull, cleaning it up and "priming it" and then making it good! they were back to sea on the next tide. the day before yesterday a large FC boat was lifted in the yard and the bottom cleaned and antifouled and the topsides painted! it was back in the water in about two hours all togeather! so it would seem that FC hulls are not too demanding when it comes to Maintenence and repairs. Isnt there a reef in NZ where many boats have run aground and the FC hulls last the longest before break up? do I remember correctly, a post appertaining to this?

02-12-06, 11:59
The cement IS VERY MUCH part of the structure, as is the steel. It is BOTH that combine with the relative merits to produce a sound hull.

NB! Concrete is not used in the construction of ferro-cement boats, as this contains agregate. (SR) Cement, sand and water is all that is used.

Ferro-cement is, in fact, less dense than glassfibre.

The thickness of a ferro hull is typically less than 1". And 3/4" &amp; 1/2" are not uncommon.

The weight of a ferro boat is fairly similar to a traditional frame-built wooden boat of the same size.

Steel and Aluminium are acceptable for boat construction, but both require a lot more skill to produce a good boat than FC construction. Quicker though.

Steel corrodes by rusting. The steel in a Ferro Hull is encased in cement, and so does not rust. I have seen this for myself.

02-12-06, 13:44
In the process of repairing a 1970's Hartley 48ft


The steel in a Ferro Hull is encased in cement, and so does not rust

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In theory yes , in practice due to small cracks in the concrete No. This is either due to cracking during curing or by small dings during use allowing water (seawater) to get into the reinforcing and cause corrosion either by rusting (oxidiation) or as in my case by having no anodes on the structure which allowed cathodic corrosion.

I have several areas where the steel reinforcing has corroded away without rusting. I have an area approx 1m x 1.5m where the reinforcing has disappeared I know this is not by oxidiation (rust) as the volume of the reinforcing increases by a factor of about 11 dur to rusting which would crack the concrete and causing rust bleed. In my case no rust bleed just reinforcing disappearing.

This can now with the moden epoxies be solved using the techneque as used on wooden boats with the "west system"

I have also found a product used in the repair of reinforced concrete bridges and other structures that will coat the steel with a corrosion protection coating by migrating through the porious concrete and surounding the steel bars.

I have not used this yet but have seen several structures done this way and it looks sound

I plan to use this migrating corrosion inhibiter then seal inside and outside with west type epoxy following the replacement of the corroded reinforcing.

I will then weld anode connection studs to the mesh as is done for steel boats. There two technequics should protect from both kinds of corrosion.


Steel and Aluminium are acceptable for boat construction, but both require a lot more skill to produce a good boat than FC construction. Quicker though.

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Depends on your method of construction. If round bilge more skill is required for steel or aluminium but for hard /multi / strip chine I dont think alot more skill is required. The skills requires is welding for steel / aluminium and good plastering skills for ferro construction.

02-12-06, 15:12
Sounds like you've got some very serious structural problems there, inherent from the build. IMHO scrap the hull :-(

But on the other hand, FC construction lends itself to creative repair techniques :-)

02-12-06, 15:26
Plan is :-

New steel yacht to cruse Indian Ocean OZ, south east asia and Pacific Islands when retired and put ferro in KZN yacht club as base then sell house, busness. other goods and property, invest results to provide income to go crusing in next 2-3 years

02-12-06, 17:03
But on the other hand, FC construction lends itself to creative repair techniques :-)

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A mate of mine repaired his FC hull and included the ashes of a late pontoon neighbour in the patch. /forums/images/graemlins/laugh.gif

02-12-06, 19:03
Windboats now "Fit-out" some fine Oysters
superb quality

02-12-06, 22:06
Thanks for this. I will be sure to be very nice to your neighbour and avoid ending up as concrete filler....

03-12-06, 07:58
Re:- the repair done by the guys I mentioned above (Their reinforcing mesh had erroded away due to "electrolitic action") was made by replacing the steel mesh to a slightly larger area and then rendering with a quick drying Ferro cement. the inside was a little lumpy as it seemed to have to be a little thicker than the original hull but the outside was a fair finish which they said they would "epoxy fill" smooth at some later date!

03-12-06, 16:36

The steel in a Ferro Hull is encased in cement, and so does not rust

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As an hartitect and therefore not qualified to venture an opinion on such matters without my tame structural engineer to hand, I also insisted/expected (rule of thumb) on at least 25mm of concrete cover over the steel reinforcement. I guess this probably has a lot more to do with frost/freezing protection and spalling prevention, but I am surprised to hear how thin FC hulls can be. Didn't realise that. But of course, concrete contains aggregate, which these hulls don't. Nevertheless . .

04-12-06, 12:28
The cement mix is generally 1 part cement 1.5 parts dryed graded sand amd 0.5 part water which makes a very stromg mix
My hull is average 25 mm thk but the deck can be 20mm thick to keep weight down.

Covering over rebar is 3 mm approx.

Don't get much frost in the tropics

As an architect do you know of Cortec who do repair products for concrete structures and do you have any comments.

info http://www.cortecvci.com/index2.php

06-12-06, 09:54
Unfortunately not. a) They seem pretty American and my experience is UK-based b) Never was much into this kind of deeply structural hoopla (know my limitations and recognise the expertise of other professionals) c) Haven't practised architecture, as such, in anger, for about 15 years.
However, they cite SBD on their website (although no link), who are part of Weber(+Broutin) and who were one of our regular (marketing) clients (before we sold up and sailed!).
Gawd knows if any of this makes any sense or is in any way helpful, which it probably isn't.

07-12-06, 12:22
I've got an Endurance built by Windboats, and a lovely thing she is too. Strong and seaworthy, although at present a bit of a nightmare as we're trying to finish an epoxy/coppercoat/repaint topsides job that we started in August expecting to take 6 weeks /forums/images/graemlins/crazy.gif However once it's done she'll be nearly ready for the grand move aboard in March.
Incidently, before we found her we looked very seriously at the boat now owned by CodStewart. We thought she was absolutely brilliant, but sadly since our plans at the time involved bringing her back to Europe, the wonderful burocracy put paid to that. /forums/images/graemlins/mad.gif
Glad she found a good home!

07-12-06, 12:45
That's nice to hear. Folks down in Mexico think she's a good boat, too. She deserves to spread her wings and go for a good old voyage.
I'll make that dream come true for her.
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09-12-06, 19:28
Isn't coppercoat not recommended for ferro boats? Don't know why.

09-12-06, 20:13
I think you're thinking of steel and aluminium because of the possible electrolytic effects. I'll tell you in a while if there's any unforeseen ferro effects /forums/images/graemlins/ooo.gif

10-12-06, 11:00
Same as for steel boats. It set up a great battery and either corrodes the steel in the ferro hull or starts with the anodes. if fitted and then the steel.
I have both a ferro and a steel yacht