And, basic concrete does allow water infiltration which would make me worry about the steel reinforcing.
Arrrr, now ya see, this is the biggest misconception out there. The cement plaster IS NOT CONCRETE! The plaster is a very different product. As different as Epoxy vs Ester. They may both have many similar characteristics, but they are very different products.
i think the point is that without breaking into the hull and seeing whats in there and what its doing ,
Now this is the other miconception that tags onto the first. There is no need to know what is going on inside the hull. The fact that it is Cement ensures that the steel is being kept safe. The very high concentration of lime in the plaster and along with a few other chimicals in there, ensure that the steel is very well protected. At the time of build, the best thing to do is actually allow the steel armature to rust slightly before the plaster is applied. This is because a chemical reaction takes place and the rust is converted to a stable iron product that stops rust form conitinuing. This allows the plaster to also get a "grip" of the steel rod better.
One of the major advantages of the cement plaster is that it is subject to reverse Osmosis
I have now seen repairs
done, that when the concrete was broken away, the steel rods inside looked possibley better than the day it was first placed. Certainly it was in great shape anyway.
But there is defintaly some valid concerns as well. How DO you know if the hull is OK or not. This concerned me when I first came into contact with FC, but I have scince seen a few hulls and now understand a lot more. Firstly, the biggest mistake made was the cement mix. Mainly in the sand medium used. It is important..no, Imperitive that the correct sand is used. I have scince found that it is very easy to spot the "bad" mixes. The sand needs to be clean, washed "sharp" river sand. Big mistakes
were made by using beach sand. I have seen one hull that there were more shells in it than sand. Salt
is the biggest killer. It dissolves in the wet plaster, but as it dries out, the salt
crystillises and fills spaces that the sand should be. Then when it gets wet from rain,t eh salt washes out and the hull is left porouse. Very easy to spot as the hull literaly eats away and gets a white powdery stuff all over it, which is salt.
Apart from that, the other areas of concern is in the construction itself. How thick is the plaster? and how have deck
fittings been held down. And how much as the builder
used his own creative licence to go beyound the original design. If the orginal cabin
top was sugested it should be ply, then IS it ply or cement. If the use of cement up high was not designed inthe original concept
, the boat will behave something terrible.
Oh while I remember, another misconception is the keel
Ballast. Steel punchings are often used for one very simple reason. Lead and Cemement do not like each other. Once again because of the chemical properties of the cement mix, placing lead into it results in a product called Lead Plumbate. The cement will NEVER set. It stays this mushy mess. So steel was the simplest thing to add to the Keel
. It doesn't matter what goes down there, just as long as it meets the designed weight once again.