Buying A Ferroboat

Buying A Ferroboat

In the boating world you will from time to time hear the comment 'the problem with ferroboats is they don't sell for as much'. Or 'I couldn't get as much for my ferro boat, as some of the other boats around her size were selling for'. And that's usually where those statements end, without any further quantification. In many cases their comments are quite true because......a/ they are generally trying to compare an amateur built ferro boat with the value of a professionally built one of GRP or aluminium or wood etc.... or b /they have forgotten that the ferroboat usually cost considerably less to build than most other boats, so why consider it to have a greater value ! And for the buyer, that means that generally you will get a lot more for your money (when talking of over 25ft)

The question of suitability or quality of amateur as against professionally built ferroboats often arises. It is not normally the amateur constructed boat that is the problem factor, but the amateur designed boat that is the root cause of most adverse ferroboat stigma. Because the medium of construction is a/ relatively simple. b/ requiring relatively minimal equipment. c/ low cost in materials (although high in labour it's a plus for the amateur). It unfortunately attracts the would-be instant self-taught designers in hoards. Many of their monuments are to be seen worldwide. Generally either abandoned because of the realisation that it is no more likely to perform better at sea than a 'brick shit-house', or that their lack of design knowledge was no less than their knowledge of simple monetary arithmetic to either finish or transport it. The problem for the the amateur designed ones that reach completion (or near completion as the ad's often read), and sometimes neatly painted awaiting you to discover that there is more to a boat than a sharp-end, a blunt-end, with the biggest deep-freeze you ever saw, and ornate carvings about the place. Often accompanied by the expert owner/builder/designer bedecked in beard, cap, jersey and pipe....who has never made it out past the harbour entrance in anything other than the local ferry.

To a lesser degree, a further problem that the purchaser must be aware of (as with any accredited design), is unqualified alterations and deviations from the set design and specifications made by the builder, (both amateur and unfortunately professional). Our nightmare as designers, is when after supplying plans of a vessel to a builder we are informed 'that he has improved something'. This scenario is not confined to the amateur builder. As examples....a company in the English Midlands, altered the material specifications for the armatures of the boats they built in an effort to cut costs (they used expanded metal mesh 'Expandamet', instead of twisted wire netting or square welded mesh as specified). After a spate of legal cases against boat transporters and boat yards for damaging their vessels by the new owners. It was obvious the company had soon realised there was something dreadfully wrong with the impact strength of the boat hulls, because they quickly closed down the business, with the management melting in to oblivion. All came to light when I was called in to advise on a claim against a Southampton boatyard for negligence in damaging a 60ft ketch when hauling out. On inspection I found the cause why the hull had so much damage to it in the keel area, and at the points where the pads on the props pushed against the hull was.....the hull was not able to withstand pressures of it's own weight without damage. That not only were the armature materials inadequate, but the plaster mix was lacking in cement and had little strength (probably not cured properly either). What was even more disturbing for the new owner of the vessel (it was several years old by this time), was that he had bought it with four survey reports issued by different so called 'qualified surveyors', giving glowing reports of the vessel. On inspection of these reports, as I have found many times over the years. They were just what is known in the trade as 'rivet counters'. They just provided pages and pages of of descriptions of every screw, nut and bolt etc that the craft consisted of, and mentioned any deterioration or lack of it to the same etc. No mention of hull, nor was there likely to be as none of them had any expertise or experience with the medium to pass any serious comment on. But they were happy to take their clients money for a so called 'survey'.

The other species which the ferroboat owner/prospective purchaser should be extremely cautious of coming in to contact with is the 'tapper'. He arrives on site with small hammer and clipboard, and proceeds to spend the next few hours acting the part of a woodpecker, tapping over the whole hull area with his little hammer. When confronted he will announce he is checking to see if the hull is any good by 'looking for voids'. He won't be able to advise how they got there, whether they are detriment, or how to fix them. But just list where he thinks they are along side his 'rivet count', list. Ensure that the person you get to survey for you is competent to offer advice on that kind of craft, as well as it's method of construction. The statement that 'he has done many others like it', stands for nothing.

I had reason recently to come in to contact with a 'boat sand-blasting expert', who had advised a ferroboat owner that he should blast the paint off the hull for him, and that there would be no problem as 'he had done many boats before'. After his 4 hours work, I advised the owner that the damage to the hull would cost (if possible to rectify), in excess of $12,000, and a further minimum $10,000 to attempt repair to the sand blasted deck. Having seen the hull built some 15 years earlier, I can vouch that as being more than it's original cost. It turned out as expected, that he had been regularly employed blasting gel-coats off GRP hulls with osmosis or sun deterioration problems. If you are considering removing the paint from a hull by blasting, as an easy way out, you must ensure that you get a guarantee in writing that only the paint will be removed with no detriment to the hull. If one is foolish enough to do it you will win yourself a new boat in the courts (if he has the money or insurance cover behind him).

We often come across reports on small sailing craft by Naval Architects with more letters after their name than you could fit on an A4 sheet of paper in 10 point text....who have spent their training as well as their career involved in steel vessels of a minimum 300 tons. Their report is likely to hold less credence than an opinion from almost any regular boat repairer in your local yard. Treat 'boat brokers', the same as you would a car-salesman, their comments and advice reflect nothing other than what affects their income. Professionally designed but amateur built ferroboats, in many cases can be just as good as a yard built one. Often it can even prove to be a better buy, if undertaken by an all-round craftsman who may have invested many more hours in to the project than any yard could afford.

There are two other scenarios to take in to consideration when contemplating the purchase of a ferroboat. The first was the brief entry in to the ferroboat scene by designers with success in other mediums, with no grounding or experience of the use of ferro-cement in a marine application. Without need to mention by name, there were several who tried to cash in on the market by adaptions of existing methods during the 70's, who quickly got their fingers burnt and then discreetly withdrew from the scene. Leaving us and others to help the stranded builders world-wide who bought plans by mail-order with no further back-up advice available. This scenario did much damage to the medium of ferroboat construction, and does still more by these designers continued adverse comments made in order to cover their own mistakes. Their most common mistake being unaware of the 'weight variance factor'. To design a boat for a third-party to build at a distance without constant direct control, in wood, plywood, steel or aluminium with specific finished material sizes, and end up within fairly close weight tolerances is one thing. But to supply plans for an amateur to build a hull in ferro-cement, where a number of very slight deviations or minor lapses in care can easily increase the weight of a 40ft hull by as much as 5tons is quite another story. Only experience of the construction method could foresee the problem, and allow for adopted measures to minimise the consequences from catastrophe to acceptable sailing ability of the finished vessel.

The second is the adaption of existing successful designs in other mediums into ferro-cement. Some will and some won't for many reasons, and the prospective purchaser should be aware of this. The factors of 'ballast to weight ratio', (in both directions), changes in flexibility, and weight re-distribution are just some of the effects on the replica transfer in to any other building material. The re-distribution of weight (still at the same displacement), can have serious effects on the way of a vessel, and subsequently it's sailing ability. As many have found when replicating an old wooden design in to so-called modern GRP construction. The worst scenario is replicating a vessel previously fitted with internal ballast. The inexperienced will announce 'an improved sailing ability', unfortunately being unaware of the dramatic change to the vessels motion. Sometimes to such an extreme that on some replica square-riggers, it is almost impossible to put anyone aloft in any kind of a sea, without being flicked from from the yard-arms by the adverse pendulum effect.


The only types of netting/mesh suitable for marine use is either galvanised netting of half inch dia hexagonal known as 'Bird Netting', or half inch square welded mesh. In a concrete/ferro-cement compound 'Bird Netting' is greater in strength, flexibility and impact resistance. Do not use 'Chicken wire/netting' it has 1 inch hexagonal dia spacings and so does not contain enough steel content.


Under no circumstances purchase a boat if the hull has been built using 'expanded wire', often sold as 'expandamet'.. It is manufactured from a flat sheet of steel by cutting small slots and expanding it. In a concrete/ferro-cement compound it has a very poor impact resistance. The layers are not integrated as with netting and so seperate easily under impact. Experience has shown that the very few vessels that have used this method of lay-up have mostly been condemned after very little use, and larger ones found unable to support their own weight on the hardstanding.

Some important points worth remembering......lighter is not necessarily better....nor is a lower ballasting level (do not confuse the parameters for speed with general sailing/cruising)......there are no nightmares about the state of the keel-bolts in a ferroboat.

Colin Brookes. mSNAME, amRINA.

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The information and comments given on this 'World Of Ferroboats', website are based on first-hand experience gained by the contributors over many years of use, designing, surveying, building and repairing ferro-cement boats.