Cruiser Wiki Click Here to Login

Join Cruiser Log Today

Cruiser Log World Cruising & Sailing Forums

Cruiser Log World Cruising & Sailing Forums (
-   General Cruising Forum (
-   -   Just how tough is ferro anyhow? (

haiqu 11-26-2012 11:34 PM

Just how tough is ferro anyhow?
1 Attachment(s)
The Hartley Tasman pictured below broke mooring at high tide during a storm and careened down river into a bridge. As you can see it hit hard enough to tear the side rail right off. I'd estimate the cost to repair (materials) as less than $200. Try that with your Bendy Toy ...

capta 11-27-2012 12:52 AM

A friend made a small mistake and put his cement boat on a reef in Hawaii.
After 3 days his boat had dug itself so deeply into the reef a crane was required, rather than a tow, to remove it. After 5 days it did wear a small hole in the boat, about a foot square.
Not all ferro boats are equal, however. If the steel rebar and wire are allowed to rust before the concrete is applied, then problems will develop. If the cement is not properly applied, then problems will develop.
A properly built ferro boat can be a fantastic vessel, but knowing whether it is a well built vessel is the question.

mico 11-27-2012 01:49 AM

Surprised and chastened
I have often wondered if the resistance to ferro boats has more to do with their initial layup and final finishing rather than their materials of construction. Too many look like they've been built behind the backyard dunny with a garden trowel and leftovers from cementing the driveway - with any timbers used, cobbled together from dismantled verandahs and weekend renovation leftovers. :p


I've recently seen some ferro vessels that are absolutely beautiful, professionally built, expertly fitted out and no expense spared in their equiping. There's one I'd still swear was a F/G vessel if the owner had not shown me her construction photos.:eek:

I'm the first to admit significant ignorance of ferro boat building but the opportunity to be shown around these last three beautiful vessels was a real eye opening and challenged many of my preconceived notions of their worth as sea going vessels

All used an epoxy resin mix rather than water as a wetting agent in their cement making and all took significant effort in ensuring their forming and framing were professsionaly done and all steel bar well surrounded and secured. All the owners constructed a weather proof shed for their build and took great care to ensure all steel and mesh used was free of rust and corrosion. Timber work and cabinetry was professionally done and the final faring and paint finishing left them looking like they had just popped out a F/G mould.

I guess as Capta points out, knowing how well they are built is always going to be the question but given their low resale value, you'd be getting the bargain of a lifetime if you stumbled across one like I've just discussed for sale.

Fair winds


Auzzee 11-27-2012 03:32 AM

These days it is simply too expensive to build ferro boats. This leaves us with a choice of premade vessels. The oft repeated bilge about ferro boats is "I wouldn't like to put to sea in a poorly made ferro boat".

I wouldn't like to put to sea in a poorly made boat, irrespective of the medium used in its manufacture.

If buying a used ferro boat look inside the hull for heavy woven fibreglass rovings below the waterline and up to the deck head in areas ahead of the forward bulkhead. If they don't exist, look for a different boat. When assessing the worth of the vessel, employ someone with a mobile x-ray machine to systematically check the hull during survey.

I have had ferro boats and they are wonderful, low maintenance craft.

This does not alter the fact that when buying ferro, the buyer should be aware of the pitfalls...Well built ferro boats are more prone to catastrophic failure than are well built boats made from timber, steel, glass or aluminium.

mico 11-27-2012 05:54 AM

Is that why Ferro boats have the sign near where you board saying No smoking..No shoes and no jack hammers?:lol:

linnupesa 11-27-2012 07:28 AM


the beauty of cement is the price of the materials. But labor, if done well becomes an immense and backbreaking task. To cure the concrete to maximum strength requires a relatively cool 70F. The proviso is it cannot be left to dry out fully, else the chemistry stops. With water present, curing will go on forever without stopping. Strength will still increase but after 30 days the curve flattens out a lot.

The comment about water-less cement is a bit of a misnomer... it just cannot happen. Also, I'd say commercial operations will likely try to hurry the curing. but one month I'd say is what I'd be happy with.

I've been building an in-ground poured/vibrated concrete water tank, 28ft diameter, with 6" walls and have also built a raised foundation that went through a major house fire without any damage. All thanks to good curing, is my guess. Other fire damaged concrete just crumbled apart.

The fibreglass is possibly used to seal in the water or is a composite type of construction of two materials. True concrete needs water to cure, but fibreglass hates water while curing. I don't know anything about what you mentioned about FG roving but expect it may act like those glass-filled plastics, adding great tensile strength. Concrete is of course very poor in tensile strength but is superb under pressure.

Ivo s/v Linnupesa

Auzzee 11-27-2012 07:57 AM

^The rovings are epoxied onto the inner surface after curing has taken place. It becomes a very tough, flexible liner with about 5mm thickness. It main purpose is to overcome or limit puncture damage.

Cement company Monsanto developed a cement based plaster which was polymer (not epoxy) impregnated. I can't remember what it was called, but it was very expensive and left a hull which they claimed to be more durable and impact resistant than steel.

linnupesa 11-27-2012 09:07 AM


thank you for cluing me in there about the FG purpose. It makes good sense if not good advertising copy but I wonder what the drawbacks might be. The source of a little seepage for instance would be hard to identify and/or to repair if hidden like that.

Strength-wise I think we've seen nothing yet what can be done with concrete and ceramics. I think even some tanks use kevlar/ceramics to protect against AP hits.

I've worked with Mitutoyo ceramic gage blocks that supposedly outlast steel and you never need to worry about rust either. Now combine that with a non-rusting carbon or kevlar-type fibre and you should have a truly Somalia-proof hull. ( Lloyds RPG-rating anyone?? )

Ivo s/v Linnupesa

haiqu 11-27-2012 10:48 AM

Well the only water getting into mine is through portholes that some bozo tried to fix with Silastic when he should have greased the screws. Other than that she's quite cozy as I sit here listening to the rain on the roof. Not bad for a 40yo boat, I'm fairly happy with the stuff.

linnupesa 11-27-2012 03:36 PM

Mico or Mr Choccoboozo ( No, no, not Bozo! )

How is noisiness below deck in a seaway? I like the idea of steel or alum hulls but have never experienced one in a rough sea. All metal seems to be great at transmitting noise and vibration and I am wondering if the cement component is able to attenuate and absorb some noise? How is condensation? On a par with FG?

I've no idea and would appreciate your experiences. Back in SA I was thinking of building a ferro hull myself. Then I saw a steel one built by some professional welders, who over-specified everything. If it hit a bridge it would have gone right on through it but as to sailing... it already was dragging behind the fleet right out of the gate from Cape Town and came in last on that CT to Rio race. There's always a downside or compromise to be made, ain't nuttin free.

Ivo s/v Linnupesa

Cap'n Jack 12-01-2012 12:47 AM

My lady and I built a ferro boat 41 years ago and she's strong enough to take anything the sea dishes out. Somewhere in excess of 150k miles on her and still the hull requires little maintenance. We cured our hull for 30 days with irrigating hose along the gunwales dripping continuously. Did the trick. Filled the empty hull with water!
One caveat. Running a ferro hull up onto a reef can prove fatal if they lay over on their sides, such heavy weight lifting and pounding can fracture them and then they break up swiftly.

haiqu 12-01-2012 09:17 AM


Originally Posted by Cap'n Jack (Post 36498)
One caveat. Running a ferro hull up onto a reef can prove fatal if they lay over on their sides, such heavy weight lifting and pounding can fracture them and then they break up swiftly.

I'll try to remember not to do that. :huh:

haiqu 12-02-2012 04:05 AM

Well, call me a crazy, impetuous fool but I just bought this one off ebay.

"You crazy, impetuous fool!"

haiqu 12-10-2012 10:32 PM

Now thinking about SMS anchor alarms for this one. Anyone have a recommendation for something that works in Australia?

anilkumar 03-06-2013 08:28 AM

Never used such thing. If its really challenging then i would definitly accept the challenge....

All times are GMT. The time now is 02:35 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.0

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

RV & Travel Trailer Communities

Our RV & Travel Trailer sites encompasses virtually all types of Recreational Vehicles, from brand-specific to general RV communities.

» More about our RV Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

All times are GMT. The time now is 02:35 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.0