Fay Marine Photographs 3
At this point the framing will be in line fore and aft and will only need the frames to be set square to the centre line. This can be done by measurement but I use a large light weight wood square which I made for this purpose. It is easy to make if you remember that a right angle triangle can accurately be made by making sure that one side measures 3, the next 4 and the longest 5. this can be feet or metres or inches. it must just all match.
The square sits across two centreline uprights to accurately position the frame. If it is kept tight into the angle between the headstock and the upright it can be used all round the frame.
Making sure that everything is correct and square takes a while but time spent now will save time later
This is a really interesting picture. It shows many aspects which I will try to explain. This is a my personal Fay 40 Radius chine yacht during construction. First note the 3" x 2" temporary timber building frame. There is an upright under each frame position and several triangulation pieces to ensure it can not twist and possibly collapse. When the frames are constructed they have temporary supports welded to them. These are known as 'headstocks' and 'centre line uprights'. They have several functions. They support the frame and keep it and later the hull square. The headstocks sit on the temporary timber building frame and should be accurate enough to sight across or better still to have a thin line stretched across them to ensure that they are in line. I drill them and screw them to the timber, using thin shims of wood to ensure they are accurate. Also they are great to put temporary staging on so that the frame is easy to reach all the way round. I re-use the plywood that the frames were set out on. The centre line uprights are used to ensure that the hull stays in line fore and aft. If a large hull is being built these may need a support down to the floor to take the weight as the hull is plated. A string line helps to keep things straight here too.
This yacht has no chine bars, only stringers, however it should be made very clear that it is unwise to weld either stringers or chine bars to the frames until the hull has been plated. This is because without welding, the chine bars/stringers will make a nice curve around the frames. As soon as they are welded to the frames they will bend (or kink) around the frame and go 'flat in between each frame. This is because as soon as heat (welding) is applied to the bar which is forming a gentle curve, it bends at each point of support (frame) and re-assumes its natural tendency to be straight. I can not emphasise this enough. We use thin line to hold the stringers/chine bars in place as can be seen in the photo. if there is a need to 'tack' weld then we support the bar each side of the frame and use the minimum amount of weld possible. I can not emphasise this enough as along with welding the frames to the hull plating and over welding, this is one of the major reasons for home builders producing an un-fair hull.
This hull is radius chine which appears round bilge and it is only us purists who seem to differentiate these days. All that aside it is interesting to note that on the inside of the radius section the frame plate is cut as two straight sections. This is purely to make fitting the interior battens and plywood lining easier.
My gas bottles can be seen at the far end. Ok for me but I have 60ft hoses to reach everywhere.
On the left of the picture, can be seen a line of steel plates laid on the floor. For this yacht all the flat topsides and lower plates were lofted in the computer so that most can be pre-cut without templating or offering the plate up and marking for cutting. The plates are laid edge to edge in a line and either a string line used as a straight, or one edge. A line is marked across the plates every 12 inches, then from the edge or string line two measurements are marked. One for the top edge and one for the bottom edge. All the crosses are joined and checked for fairness before the plates are cut. Once cut and cleaned each plate is laid onto a fresh sheet of steel, marked round and another plate cut for the opposite side.
ŠPaul Fay 2004