Deep Freezing Ferro Boats

[MainlySteam]

The comment has been made to me that ferro cement vessels cannot stand freezing climates due to the moisture in the cement freezing and the expansion causing failure of the cement (obviously mainly above the waterline where the hull temperature will fall below that of the seawater the boat is floating in). Am not talking about a frosty morning type event but for the likes of Scandinavia, Alaska, Canada, etc type permanent freeze ups.

I have no idea if this is so, and wonder if anyone has any first hand information or experience of this.

Thanks

John

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[ongolo]

Hi John,

That would make sense.

I have seen a ferro that leaked so badly, it needed al 6 solar panels just to keep the bilge pumps going. Then in Simons Town, a 45 footer sank on its mooring with out frost of course (most beautiful finished inside) and I saw a ferroboat in Saldhana Bay that was for 2 weeks on the hard and water still came out of the hull skin so to say. It is difficult to describe, the water would stop, then after 5 min or so, maybe a half of cup came out, then nothing for 5 or 10 min. Like a tap that is full of water and lets it go for apparent no reason.

I could imagine, that hull would crack up in frost. In Hout Bay a ferro hull 50ft or more, came adrift and hit the shore, it had a gaping hole of about 1 x1m in its stern. It did not sink because of a bulkhead.

A steel hull would have had paint problems under similar circumstances, a fiber glass hull may have eventually developed osmosis.

I hope you dont have a ferro hull, however with your knowledge, you would not do such a stupid thing. Then when they were introduced, it was not stupid, it sounded good at the time.

regards ongolo


Stones should not float.

regards ongolo


<hr width=100% size=1>So what......... it floats

 

[Rick]

Never heard the theory before - do concrete buildings crack up as a result in freezing climates?

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[MainlySteam]

I had not heard of the theory either. Came up in a discussion about a boat which is planning to go to a freezing climate for a cruise and it was mentioned. Don't think the owners actually know one end of a boat from the other so they may not even make there for us to see the results of the "experiment" /forums/images/icons/frown.gif.

From the little I have found it is not generally a problem with buildings, possibly because of the heat load in them. I have seen some stuff about the importance of taking the foundations below the ground freeze/thaw cycle. Certainly concrete driveways, etc can blast the surface off with freezing and thawing cycles as we have experienced that ourselves whilst living in a freezing climate.

I understand, but have no real knowledge on, that in areas subject to freeze/thaw cycles the concrete may be air blasted during mixing to entrain air bubbles in it which allows expansion from ice crystals without blasting the surface off the concrete. They apparantly also add extra cement but whether this is to help with the freezing or to add the strength lost from the air bubbles I do not know.

John

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[MainlySteam]

No Ongolo I don't have a concrete hulled boat and have to say that I would not ever do so. I do appreciate though that it is the only way some people can get into sailing with a second hand boat of the size they want.

Like yours, our boat is steel but I have no bias against the other mainstream constructions. If ever had another boat built for myself, very unlikely, I might consider aluminium - but both steel (from the point of view of protection from corrosion) and aluminium, and indeed frp composites with kevlar and carbon in them have all come a long way in recent years.

Yes, when the freezing thing was mentioned to me I did a double take from the point of view that it seemed feasible. Also, while the corrosion processes in the armature would be slowed by low temperature, I would assume any water in there would blast the concrete when it froze. In a better vessel with only absorbtion of water into the cement, I would not like to say (although all of any age I have looked at closely have some evidence of corrosion of the armature with red weeps out of slight cracks in the cement - but have to say I do not take that much notice of them).

John

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[richardandtracy]

I think that most good condition ferro boats are probably OK.

When concrete is made it requires a wet mix that is then dried out, which leaves some expansion space within the material. This should be enough to take up the normal expansion of ice provided that the material is not saturated when frozen.

The problem is likely to occur when there are already cracks in the ferro that can let water in. The water freezes in the crack & jacks it open, allowing more water in for the next freezing cycle. This will continue until something breaks off or the crack goes right through (glug!). The things that exacerbate this are residual tensile stresses in the ferro (hogging of the vessel maybe, or possibly bad build quality) and lots of freeze-thaw cycles. If the vessel were to be taken to high lattitudes and only freeze once, it's unlikely that any extra appreciable damage would occur whatever the prior crack state of the concrete.

The other way for ferro to be damaged is by surface spalling in temperature extremes. The outside shrinks/expands with the ambient temperature, while the core does so on a much smaller scale. This sets up stresses within the concrete that can cause a scale like lump to fall off. This is most likely to occur where there is a huge diurnal range (like in a desert - difficult to go sailing there though!). However, the sea tends to have a smaller daily temp range, so this method of failure is less likely than the jacking mechanism. However, if the external temp is -80C and the interior is maintained at a high tropical temp, you're asking for trouble, but then sailing will be somewhat difficult anyway.

Regards

Richard.


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[silverseal]

Once upon a time before I was begat, Mr Hitler caused a war. To feed the island of Uk and later Europe, the Canadians built thousands of ferrocement grain barges which were towed across the pond. These were of course built as temporary measure and not expected to last for more than a few months, because of all the arguement in the posts about ferrocement and freezing, expansion and contraction, voids, poor layup etc. The river Medway if full of the bloody things, acting as floating walkways, harbour walls etc. I sank two to protect a man made harbour and I can assure you they were very hard to sink even with pneumatic drills, and 60 years on from when they were made.

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[fluffc]

I am quite annoyed at the amount of downtalking that is being done to Ferro Boats. All of the negative comments listed above in this thread are based on hearsay. All the positive comments are based on FACT.

Please do not down grade ferro boats on these basis.

I do not say that all ferro boats ever built are good. There are some quite horrific examples out there, but there are many superb ones.

The "problem with ferro" is that it is very easy to build and work with. And it is also very easy to make big mistakes. It is very labour intensive to build but relatively cheap - ideal for the "home" or DIY builder.

Would you buy a glassfibre boat, or even a wooden boat, that had been built as a DIY project? You certainly would think twice. Likewise ferro boats. Buy a proper yard-built one; or one that has a Llyods certificate (of build) and you shouldn't have major problems.

No go out and sail some proper ferro boats and stop commenting until you have first hand experience!

Happy Sailing (in whatever hull material you like...)



(PS - It is quite difficult to tell a ferro boat apart from a glassfibre one if its' been properly built - are you _sure_ that that yacht over there isn't ferro?)

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[boatless]

Well said - look at any Windboats hull, very hard to tell it's not glass.

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[BrendanS]

I'm starting to think I should go buy a ferro boat, just because of the possibilities of bar room and ybw conversations and arguements I'd encounter.

Bit like owning and defending a cat.

<hr width=100% size=1>Me transmitte sursum, caledoni

 

[boatless]

It would have to be a ferro MacGregor 26 so that you could have a foot in each motor/sail camp though.

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[chippie]

I wonder if there is much use of ferro water tanks in areas that freeze. This would be an indicator. They are common in my part of NZ which doesnt freeze. Water tanks and ferro boats are very similar in construction.

I have seen a few beautifully built ferro boats , both amateur and professionally built, and some roughies, which were not professionally built. So too with steel and wood.

There were lots of ferro boats built here 20 or more years ago, there doesnt seem to be a record of lots of ferro boat disasters, maybe they die quietly.

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[Rick]

Think main issue is reason for building in ferro - which was cost - personal view is that a good ferro boat is really a steel boat in whcih the cement keeps the water out - the Sayer pro built boats are great, as was "Helsal" - the Joe Adams 66 footer that won Hobart one year - called floating footpath by the wags.

The bad ones are where the builders, on the cheap, used chicken wire and not enough steel, and lots of plaster, but applied piecemeal - good ones had lots of steel, high tensile mesh, and minimal plaster, all applied in one go, and then kept moist throughout cure (30 days mostly IIRC).

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[MainlySteam]

Hi Richard

I think that you are probably correct and I tend to go along with what you say. I believe that in freezing conditions I would personally be more concerned about damage to the hull from floating ice.

Regards

John

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[MainlySteam]

Thanks everyone. Seems not much specific experience with freezing out there.

Predictable I guess, but did not expect it, reaction from the ferro fans. But they could not answer the question either. I own a steel boat and I, and all other steel boat owners I know of, never get worked up if it is inferred that they rust, are unstable, slow, etc. There again, our nonplussed reaction might be because there is nothing wrong with steel. But must be something wrong with ferro if the ferro crowd are so sensitive about it /forums/images/icons/smile.gif - a nasty little "secret" perhaps?

John

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[MainlySteam]

<<<Bit like owning and defending a cat.>>>

Brendan

Ships Cat asked me to pass on that he thinks you are lovely as all cats enjoy being defended in bar room conversations - especially if the opposition is dogged /forums/images/icons/smile.gif.

Regards

John

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[BrendanS]

John, please pass on my best wishes to Ships Cat, along with my assurance that I think pussies are lovely too, and are preferable to an old dog any day! /forums/images/icons/laugh.gif

<hr width=100% size=1>Me transmitte sursum, caledoni

 

[MainlySteam]

In between studying up on the ColRegs (he is chief advisor here on those) Ships Cat says "Thanks". /forums/images/icons/smile.gif

John

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[Trevethan]

There are a number of those grain barges in Vancouver area in Canada -- 60 years on, and still in good nick surviving the winters in BC -- not as cold as Alberta say, but cold air tumbles off the glaciers and the sea can freeze.

btw I hav a ferroboat -- one of teh better built ones and I have to say as a material it is very easy to work with. Its remarkably flexible when applied thinly enough.

The biggest problem with ferro is bleeding -- if was gets in the armature . I have a couple of rust spots where a deck fitting allowed some water in then cause a rust blemish near by.

It was easy to fix. gnd back the cement to bright metal, apply some rust inhibitor, fill and sand backl

I used epoxy with cement as a bulking agent -- very easy. oh and of course fix the original leak site!

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[stokes]

Ferro tugs where built on the Wear at Sunderland , one launched in 1919 was in use until 1940, was then stripped out and the hulk "beached"on the bend of the river. Its still there to this day . Google Wear Ferro Tugs for more info.

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