Ferocement crack - fixable or the boat trash?

[Snowpetrel]

I remember hearing an interesting story about Bob and Nancy Griffiths second Awahnee. Can't vouch for it's accuracy... But anyway the story goes that it was plastered up over a period of a few months, doing a small section each day. When it was completed someone mentioned that it should have been done in one day and carefully cured. But still they boat went on to do some incredible voyages including sailing to Antarctica. Certainly very tough sailors. Their book blue water is well worth a read.

http://www.stexboat.com/books/circumnav/ci_21.htm

http://www.insidemystery.org/navigat...ahnee-1600.jpg

http://www.insidemystery.org/navigation/awahnee.html

https://www.goodreads.com/book/show/1949833.Blue_Water

[clockwork orange]

Originally Posted by chris95040

How are cold joints in ferro and cored construction in fiberglass analogous?

Not sure what analogous means but as a pro boatbuilder for almost 50 years having built custom and production boats in many mediums including ferro, I can tell you that there are a lot of theories floating around and then there is real life. When I was building mostly cold molded wood boats and the occasional one off cored boat by day as an poor apprentice I built my own Hartley ferro boat in my spare time. At that time the ferro boom was in full swing and there were the one shot and 2 shot proponents. I believe the majority of ferro built in New Zealand at that time were done in 2 shots primarily due to the popularity of Hartley designs. These have held up well over time as have one shot boats. What I have learned over the years is that it mostly comes down to timely maintainance with any construction material. With cored glass boats we scarf the skins just like wood and layup new glass, it is never a problem. When I built my ferro boat Ev Sayers team did the plastering and I believe there was 2 weeks of continuous water curing between the inner and outer plastering and the only bonding agent was a cement grout wash.

Steve.

[hellosailor]

Cement (concrete) can be funny stuff. Case in point the Hoover Dam was done in one continuous pour, as are skyscraper foundations. And iron rebar is used as reinforcement, but rebar will always rust and expand in the presence of water and oxygen. Yet without a high water content, concrete and cement can literally be smacked and crumble into dust.

The "right" way to get the chemistry happy is about as simple as the "right" way to baking bread and cakes. And for some folks, not me, that's about as easy becoming an NFL player of the year.

[Steve Bean]

It is common knowledge that too much water in a concrete mix makes weak concrete. The water in the mix combines with components of the cement powder to form hydrates, crystals that interlock to solidify the concrete. This "water of crystallization" does not cause rusting of iron rebar. Curing of concrete is not drying or evaporation, but incorporation of the water into hydrates. Concrete continues to cure and harden for many years.

[DumnMad]

Originally Posted by hellosailor

Cement (concrete) can be funny stuff. Case in point the Hoover Dam was done in one continuous pour, as are skyscraper foundations. And iron rebar is used as reinforcement, but rebar will always rust and expand in the presence of water and oxygen. Yet without a high water content, concrete and cement can literally be smacked and crumble into dust.

The "right" way to get the chemistry happy is about as simple as the "right" way to baking bread and cakes. And for some folks, not me, that's about as easy becoming an NFL player of the year.

Ferro construction is not concrete. Its plaster and chicken netting.

If the hull is built like concrete it will crack and rust like concrete.

[Shrew]

OP hasn't posted in this thread since 07/21/18. Either he walked away from the boat, or he walked away from the masses trying to kill his dream.

[navado]

Originally Posted by Shrew

OP hasn't posted in this thread since 07/21/18. Either he walked away from the boat, or he walked away from the masses trying to kill his dream.

Well, the real story is more prosaic.
Finally the seller thought that he found another buyer and declined my offer.
Several weeks later I found another beautiful boat and buying her.
At some point they got back to me and agreed to accept my offer, but I'm already at a new deal. fixed the crack by themselves (hammered out and reapplied the plaster) with the original materials, and made some more improvements.

If anyone wishes - the boat is the real bargain.
This is the listing:
https://www.yachtworld.co.uk/boats/1...1#.W4rWPRh9ioA

[samfreeland]

I agree. In fact I bet this boat is still on the water long after in my opinion this boat is beyond salvage has passed away.

[Steve Bean]

I hope the repair process was fully documented.

[navado]

Originally Posted by Steve Bean

I hope the repair process was fully documented.

That's the question to the current owner or his broker