Ballast & my summer holiday

December 2007 - February 2008

By early December I had all the materials to install the ballast in the keel. This consisted of 4 x 200 litre (44 gallon) drums of punchings estimated to be 1.5 tonne each, plus 200 litres of resin. One of the first things I did was make a 300mm cube (300x300x300), fill it with steel, and pour resin into it. There were two reasons for this. Firstly, I needed to see how far the resin would pentrate through the punchings, so that I could be confident that I got good penetration when doing the actual work in the keel. Secondly, I wanted to be sure of the weight per cubic metre of this mixture.

What I discovered through tis experiment was that the supplier of the punchings had been very optimistic about the weight per drum. Instead of 1.5 tonne/drum, they only weighed around 1 tonne. I contacted the supplier, who by the way were fantastic to deal with, and another 2 drums would be on the way at no cost (I just paid the freight). The supplier was Metal Skills Ltd. in East Tamaki, Auckland. Not only did they supply the punchings at scrap value, they had no hesitation in supplying more when we discussed the fact that the estimated weight had been mis-calculated.

Anyway, I also worked on various theories of winches and shutes etc etc , to work out the easiest way to get 6 tonne of steel & resin from ground level, up via the deck, down the companionway, and into the keel. Nothing I came up with was really going to work well, and in the end I bought two Stainless Steel buckets and carried the stuff up the ramp & down into the keel a bucket at a time. Six Tonne at about 25kg per bucker = 240 trips ...what the hell, I had a few weeks off.

So, from what I had determined from the "penetration experiment" I would carry enough steel into each keel compartment to be around 150mm deep. I would then mix up a few litres of resin and pour it over the top. You also have to be careful not to mix too big a volume of resin at a time as pure resin in a big volume can generate about 200 degrees C as it cures. So you get your ratio right so that the amount of steel is acting as a heat sink for the resin.

The other factor was the fumes. I would spend a few hours putting the steel in, and then pour the resin. When doing the resin I was in a spray painters full face mask/respirator. Also, by this stage it was usually mid afternoon, peak summer, in an as yet uninsulated steel hull and the tempature was generally in excess of 35 degrees C. So resin was the last job for the day. Close her up, knock off, let the resin cure, have a beer (or two).

Once all the ballast was in, there was a steel plate cut to shape and fully welded over the top of each keel compartment. There are eight compartments at 900mm long each. In theory, between the resin, and the plate there should never be any air or water enter the ballast areas, and therefore never any risk of corrosion within the ballast.