Marking the waterline.
I had read a few blogs and forum topics on this and there seem to be a number of techniques employed to do this including the use of pencils on blocks, bathtubs and talcum powder and lengths of elasticated string all of which I’m sure will eventually achieve the desired results but I think I’ll adopt a slightly more ‘Hi Tech’ approach.
First of all I don’t really know how the boat will sit in the water until it’s completely fitted out and finished and even then the waterline could look wrong so in the interests of scale accuracy I have decided to work from the Vosper drawings and do it ‘to scale’ because in reality this model will spend more time out of the water than in it so I’m not too bothered if the true waterline is a bit off.
As I’m quite a ‘DIY’ buff and I like tools and gadgets so I decided to treat myself to an late Xmas present and invest in a Bosch laser level, the model I chose has a self-levelling feature and projects very fine and totally accurate ‘cross hair’ lines. I know I will find this gadget useful for lots of DIY projects so I don’t mind the expense, (as I decided in self-justification!)
The Vosper drawings were used to scale from to accurately mark the waterline points on the bow and the stern and then the hull was placed inverted on the bench. The laser level was clamped to a stepladder about five feet away and then the hull was raised/lowered on blocks fore and aft to get the horizontal laser line to hit the bow and stern marks accurately.
The point at which the laser line crossed the rubbing strakes seemed to correspond with the same positions as per the Vosper drawing so I’m quite confident with the measurements.
A pencil was used to make a series of dash markings on the hull following the laser line.
The hull was then spun 180 degrees and levelled and the ‘laser guided’ marking process repeated.
Joining the lines across the transom and some measuring confirmed that the waterline was the same on both sides at the stern.
A final check was made by standing the hull on it’s transom and projecting a vertical line along the keel so that the projected horizontal line intersected the points at which the waterlines crossed the rubbing strakes, happily they did so within a couple of millimetres.
I applied some good quality masking tape around the hull, paying particular attention to the points where it crosses the strakes, in preparation to masking and spraying the ‘anti-fouling’ red oxide paint.