Wednesday, 16 August 2017

Cutting in the Waterline.

My build-plans make no reference to the waterline, the only mention is the draught (draft) which is 8 inches or 200 mm. Yet I need to know exactly where the waterline is, as the underwater section is red, and blue above. I can't guess where it lies because the odds are that I'd get it wrong and end up with the paint-finish looking 'skew-wiff'!!

On Youtube I watched them carry a boat out and put it in the water, then go around with a marker and mark in the waterline. No way I can do that.

I then watched how the professionals did it and larger vessels. They used very expensive laser equipment, which I can't afford...
                                                          .... or can I?
I got one from Screwfix it was made by Bosch and cost £50 ($65).

From the centre of the bottom of the transom I measured down 8 inches and marked a point. Next a spirit level was used to draw a horizontal line across the transom: the only flat surface on the boat, the rest is complex curves.

Horizontal Pencil Line on Transom

The laser leveller was now set up.

The machine self-levels and in normal conditions - setting it up 5 - 10 yards (metres) away - would project the horizontal line the whole length of the boat. As it is, I only have one yard each side which, as you can see above, gives me a short line.

The machine was moved along until the end of the laser touched the pencil mark on the transom. Marks were made with a 'felt-tip' marker at short intervals along the horizontal laser line. The machine was moved further along numerous times until I reached the stem.
The marks left with the felt-tip marker just visible 

I then repeated the process on the other side, starting at the transom. My check would come if I ended up at the stem exactly in line with the previous line. They met within a 'gnat's whisker'.

Starting aft, I place a continuous strip of masking-tape along all the felt-tip marks.

I'd got myself a waterline! It is not where I would have guessed it would end up

1 comment:

  1. Very clever! Good to see you working and posting again. So I assume you are better. Take care!