The pros and cons of ferrocement boats.

[prv]

They have several big advantages, not least that they can be repaired anywhere in the world.

So how do you repair a large hole (say collision damage) in a ferro boat? Seems like it would involve a lot of cutting and grinding back to get to sound material, and to have sound (and unaffected by salt water) mesh exposed to tie new mesh onto. Then it all needs new plastering, which we've established is a skilled job, and the join to the old material will never be as strong as the original (it was famously important when building to get all the plastering done in one day so it cured together). Of course it's doable, but it doesn't seem any more "do it anywhere" than an equivalent repair in glass and polyester. And a steel boat with a decent stick welder on board could presumably weld in a new bit of plate on the beach quicker than either. Admittedly I've not heard of people routinely carrying spare hull plating with them, but then few will have enough glass and resin or mesh and cement for a major repair either, and generic polyester and mat, or steel plate, is probably easier to buy locally than special boat cement.

Pete

 

[Seajet]

My chum with his - own built and it seemed well done, he's a serious pro engineer - 35' ferro job had a protruding bolt in a lockside somewhere like Holland punch a hole in the topsides, which he remarked was very easy to repair.

I think that's the sort of thing where the ' easy to repair ' saying comes from, if one gets a big hole it's a different matter.

As mentioned, underwater holes are very bad news as one can't fill the hole temporarily with the mesh in the way, I heard there were quite a few blue water ferro boats lost after contact with coral heads, as BurnitBlue says.

 

[savageseadog]

Just can't see the point of Ferro. GRP is more expensive but far better, the cost of the rest of it is the same anyway. I know of a Ferro boat that was incredibly heavy and floated like an fully laden oil tanker, awful.

 

[BrianH]

IIRC, a Windboat 35' Endurance, was Boat of the Show at Earls Court, but ran aground on East Coast on way home & poundered itself to complete destruction on a boulder strewn beach. No ground anchors laid after grounding apparently.

We've been down this path before (grounding on the east side of Whitby harbour entrance) and anchors or not, she would still have foundered. I lived in Whitby at the time and witnessed the sad event; no way could she have been saved as the strong onshore wind and flood tide started to lift and drop the bilge on the rock shelf she was lying on in a smother of foam and breakers. She was too far out to get any equipment to her from an inaccessible rocky beach and too far in the rock shallows from seaward. See my link in post #6 of this thread.

 

[Twister_Ken]

We've been down this path before (grounding on the east side of Whitby harbour entrance) and anchors or not, she would still have foundered. I lived in Whitby at the time and witnessed the sad event; no way could she have been saved as the strong onshore wind and flood tide started to lift and drop the bilge on the rock shelf she was lying on in a smother of foam and breakers. She was too far out to get any equipment to her from an inaccessible rocky beach and too far in the rock shallows from seaward. See my link in post #6 of this thread.

Presumably the same would have been true of a wooden or GRP boat in those circumstances. And would steel or ali have survived?

 

[BrianH]

Presumably the same would have been true of a wooden or GRP boat in those circumstances. And would steel or ali have survived?

Perhaps a strong steel boat would have just been badly dented before floating, maybe aluminium too, but still keeping basic watertight integrity. It isn't just the initial floating to survive, once buoyant and fairly upright, the keel pounding can still cause immense damage. The ferro-cement had no chance from the very beginning as the water reached her, the hull crumbled around the armature at the impact points and the water poured in. At high water she was already a sunken, irretrievable wreck, a day later completely broken up.

 

[PetiteFleur]

Many years ago we looked at a 35' ferro boat at a nearby boatyard. It was owned by a boat builder who had the hull professionally built and fitted out by himself so was in very nice condition. It was a cheap price, unusual hydraulic drive for prop, BUT the drawback for us was that no-one would give us a price for insurance so we passed it by - but we were tempted!

 

[duncan99210]

Neither of those attributes seems to add up to "horror"! Was there something else, in addition to prejudice?

Mike.

The 'horror' was that on looking at the hull it was obvious that it had been done by someone who could not achieve a consistent finish as it was marred by a series of irregularities. Looking along the hull, you could see a series of irregular dips and lumps: in combination with a hull thickness that I considered to be excessive (and I can't now recall the measurements) this caused me to question the overall competence of the builder: if he couldn't get the finish right and was making the hull thicker than necessary, what other errors were there in the build? Please don't misunderstand my position: I have nothing against ferro boats as a concept, it's just that, as others have said, there are some less than perfect examples lurking out on the market.

 

[Simes]

There are lots of less than perfect examples of GRP and steel boats out there. As for the "I once heard of" stories you should probably ask those that have owned and or sailed good distances in a Ferro boat what they think. Just to put your mind at rest I have had mine for 10 years now and would not change her. She is fast, warm, comfortable and very sea kindly. She is not regarded as heavy because she is of Ferro construct, she is regarded as heavy because of her design, she is a full keel Schooner.

As for the repair of larger holes, well you will need some galvanised steel mesh, some epoxy, and some sharp sand and some cement. Work the mesh into the exposed mesh around the edges of the hole, mix some epoxy and paint the edges with epoxy, whilst it is still tacky (kicking) make up the cement using epoxy in stead of water, plaster over the hole.
When you hear that epoxy is "easy" to repair, it means without the need of specialist equipment or knowledge.

For me the beauty of Ferro is that I got the Boat I wanted, at a price that did not break the bank and we are living our dream right now.

Yours

Simes

 

[Gordonmc]

As for the repair of larger holes, well you will need some galvanised steel mesh, some epoxy, and some sharp sand and some cement. Work the mesh into the exposed mesh around the edges of the hole, mix some epoxy and paint the edges with epoxy, whilst it is still tacky (kicking) make up the cement using epoxy in stead of water, plaster over the hole.
When you hear that epoxy is "easy" to repair, it means without the need of specialist equipment or knowledge.

Simes

The largest repair I have had to make was to a hole above the waterline when an unexpected shift in the wind strength and direction pushed the boat onto a concrete pontoon.
Four fenders shredded... if the point of contact had not been just where there was a topsides port-light she would have withstood the battering.
As it was I did a temporary repair using epoxy as Simes describes and carried on sailing for the rest of the season.
The following winter I did a proper repair and restored the port-light using a compound developed for mending motorway flyover uprights after they have been banjoed by lorries.
The pontoon didn't fare particularly well, by the way.

 

[sarabande]

Touchstone

 

[JumbleDuck]

As for the repair of larger holes, well you will need some galvanised steel mesh, some epoxy, and some sharp sand and some cement. Work the mesh into the exposed mesh around the edges of the hole, mix some epoxy and paint the edges with epoxy, whilst it is still tacky (kicking) make up the cement using epoxy in stead of water, plaster over the hole.

It's a long time since I used to teach some cement chemistry, but isn't the water a necessary ingredient for the reaction which results in dendrites growing and cement setting?

 

[Twister_Ken]

Touchstone

Apparently he wanted to call his final boat Tombstone, but Mrs Peyton nixed it.

 

[Burnham Bob]

Having sailed a 40ft+ ferroconcrete boat in an unexpected force 10 (honest guv it wasn't in the forecast!) I have great admiration for the way it ploughed through the wind and the weather. And having had Mike Peyton's boat swing into my 23 foot halcyon at anchor one night off Stone Point I know which one I'd rather have in a collision situation.

All materials have their drawbacks and their strengths. There are well built boats and dodgy boats in all materials but maybe ferro needs a little more examination than grp as the latter tend to be long production runs with their faults already exposed. Can't think of any long production run ferro boats.

 

[Lloydroberts]

Thank you for all the replies, info and pm's with offers of advice and help.

It has certainly given me 'food for thought' and more options to consider.

 

[Daydream believer]

Summing up I think you just need some concrete evidence that all is ok with the hull to reinforce others opinions but do not get plastered in the bar when doing the deal as you may pay too much for a load of hardcore

 

[JumbleDuck]

Summing up I think you just need some concrete evidence that all is ok with the hull to reinforce others opinions but do not get plastered in the bar when doing the deal as you may pay too much for a load of hardcore

Much better to get a professionally build one too - beware of armatures.

 

[Spyro]

The pontoon didn't fare particularly well, by the way.

It's never been the same again. In fact it's lying on the beach right now waiting for repair. I don't suppose it was all you though.......

 

[johnf]

I own a harltey fijian ferro yacht and love it. Bought cheaply because it is ferro but we have owned her for 8 years now and she is a joy to own. AS long as over around 40 feet then they are no heavier than other materials. Maintenance wise the important thing if rust is seen then it needs investigating early and easily treated with epoxy or mortar repair. We keep the boat in Spain and I believe that the construction keeps her much cooler than other materials, certainly I find going on board GRP boats in similar conditions much hotter. Best advice I can give is buy an old one, ours is now over 35 years old. If they are badly built the problems show relatively early on. Once over 20 years of age or so and if lasting well there is no reason why they should not continue to do so.

 

[arriviste]

In the early 1990s, I bought the 72' ferrocement schooner "Rich Harvest". (She may be seen on the Wikipedia page on ferrocement: Ferrocement - Wikipedia ). She was professionally yard-built by Derek Williams, and has a particularly fair hull that could be mistaken for a moulded GRP yacht. She became the flagship for Brighton Marina and has safely crossed the Atlantic to the Caribbean and back. At first, I was able to insure her comprehensively, but after ten years or so it became impossible to get even the third-party cover that marinas and ports require. I despair of Yacht Insurers; they are mealy-mouthed and do not properly assess the actual risk, but rely on prejudice. Even round-the-world yachtsman Robin Knox-Johnson was negative about the material. The situation now is that insurance is virtually unobtainable for ferro.