Re: Sooty Tern No. 93
Yes, a draughtsman's square is a useful thing in lofting this size of boat.
To my words "cheap white paint" add "quick drying". There's nothing wrong with using paper if you've got it, as long as it doesn't distort. I didn't use paper or paint, and my rubbed out pencil lines (and there were plenty) still showed up, which could get a little confusing at times. See my Kotik thread.
A diagonal is drawn from the centre line outwards at any convenient angle at approximately right angles to the shape of the cross section of the hull. The off-set is measured along it, from the centre line. This enables you to measure the distance more accurately than if the lines crossed at an acute angle.
Ian
Old Joke: A bench fitter works to the nearest thousandth of an inch. A loco fitter (steam) works to the nearest inch. A shipwright works to the nearest ship.
Alan Byde, Canoe Design and Construction, Pelham Books, 1978
...old maxim, 'A fair line supersedes any given measurement'.
Allan H. Vaitses, Lofting, International Marine, 1980