Fairing, Port hull

Hand Sanding

Posted by Paul

I managed a couple of hours today but it felt a lot longer. Sanding by hand with the long board is not a pleasant task and I am not as fit as I could be, so there was a lot of resting in between short bursts of work. And I am sure my shoulder muscles will feel even sorer tomorrow. Having said that, I now think I can do this. I dreaded it for a long time and the worst of it is still to come but I am getting used to it.

Before I got to work with the sanding board I marked the waterline again (so I could know what areas would be visible and those that are below the waterline) and also marked the lines on the visible chine. I started with a centreline on the point of the chine and then measured and marked a line 10mm either side of it. I have found that I have a slight incline of the chamfer, that is, it isn’t parallel with the waterline. It is 4cm closer to the waterline at the stern than it is at the bow, so it slopes down from the bow. I am not sure if this is how it is designed but I doubt 40mm over 12000mm will be greatly noticeable. It equates to a 1mm drop every 300mm. It will be interesting to see if I get the same result on the other hull. If I don’t, I doubt this will be visible anyway and certainly wont be obvious that one hull chine is slightly different to the other. This of course assumes that I have correctly marked the waterline. Perhaps I am out with that rather than the chine. Either way it is of little concern.

Once I had the chine lines marked I sanded the centre of the chine down to the 2 lines either side of it so that I had a flat area within the lines about 20mm wide. I then started sanding the flat panels above and below the chines. Here and there I needed to remark the lines and re-sand the chine flat as the sanding of the panel would impinge on the flattened chine area. I ran my hand along the chine whilst looking away so I could feel for any irregularities. I found 3 over the 12meters. I sanded the panels or sanded the chine to remove the irregularity. I think I have a fair chine. It will change again as I sand more of the panels flat (there are still high spots from the extra bog added but it is very minimal now) but I can adjust as I go. I am quite happy with this chine so far.

chine lines at bowchine lineschine lines at stern

The small taste of how hard the hand sanding is a good reason to do the essential work first, the highly visible above waterline outboard side of the hull, then the less visible above water under bridgedeck side of the hull, then the underwater sections last. The reason for this is fatigue and apathy may get the better of you and it is more likely that you will have more energy and discipline at the start so best that you tackle the jobs in order of visibility. One other area not to get to concerned about is the first 200mm of the bow. You still have to make and glass on a nose cone so there is not much point in worrying too much about getting this section perfect as you will be glassing over it again anyway.

The plans instruct you to not be too fussy about the underwater sections and I can understand why. They wont be seen so why waste valuable energy on something that is not visible anyway. I am not saying you can leave it completely but I am not going to be anywhere near as discerning on the underwater and under wing sections. I may decide to use the power sanders to finish the sanding of the re filled low spots on the underwater sections, we will see how my energy and discipline is holding out. I also still have to sand the rounded underwater chines, again I may just use the orbital. Until the weekend I get to rest again at work. Who would have thought that work would be a rest from your hobby!

Time Spent: 67.00 Hours
Total build time so far: 444.00 Hours, Total Elapsed Time: 9 Months 4 weeks

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Paul