Iain Oughtred’s Caledonia Yawl is proving to be a popular design for us. And why not? It is an attractive double-ended lapstrake sailboat that is easily rigged and sailed single-handed, yet can accommodate the better part of a cub scout troop and the dog.
We recently received a commission for the newest release of this design, the seven-strake version. It has numerous enhancements as wells as a slightly wider beam than the four strake version we have built previously. The customer prefers the sloop rig over the lug yawl, which eliminates the mizzen mast, yard, boom and boomkin, and can use a more conventional straight tiller.
The CY is based on the traditional lines of Norwegian and Shetland open boats. She is seaworthy and comfortable, with a spacious interior. She is capable of carrying large loads yet light enough to be easily handled in the water or on a trailer. The beaching rudder and easily raised centerboard allow her to navigate shallow waters under sail or by paddle or oar. Numerous configurations for the interior allow each boat to be built to the unique requirements of the customer.
We got started by setting up the ladder frame at a convenient working height for lofting the boat. Lofting on the shop floor is much too hard on the back and knees. Due to other projects in the shop, we set up the lofting in the side yard where we have plenty of room.
Lofting is the process of converting the scale drawings from the architect to full-size using the offsets (measurements) provided with the plans. This allows us to make the necessary station molds that establish the shape of the form that the hull is built on, and the patterns that will be used to build the interior components. Lofting also ensures that the hull components will fit together correctly.
Iain provides full size paper patterns that can be used instead of lofting the boat, however we have found that the time spent lofting the boat is well spent, since it allows us to work out the shapes of components without resorting to the less efficient “cut and fit” method.
We laid out sheets of particle board to create a long 24’ x 4’ surface. We then nailed sheets of 1/8” door skin painted flat white to the particle board. We then draw a grid to create the three views we will need – the profile, half-breadths, and body plan. The profile view is the hull seen from the side, the half-breadths is seen from above, and the body plan is seen from the bow and stern.
Lofting the Caledonia Yawl
We then created a series of tick sticks that contain the measurements from the chart of offsets provided with the plans. We use these sticks to mark the location of the offsets on the grid.
Tick Sticks containing the measurements from the table of offsets
Then, using a stiff batten, we connect the dots and create a fair curve. Battens are best made from soft woods; Spruce and Cedar are good choices. If the batten is rectangular rather than square in cross-section, it can be used for a wider range of bend radius. Always use the stiffest batten possible to ensure the batten doesn’t easily deflect, and give a false contour. Drill a hole in one end and hang them from a nail when not in use, otherwise they will deform over time. Sometimes I paint them black, which can help visualize the long sweeping curves.
We do this for each set of measurements, comparing the resulting drawings with each other for consistency. Here we are showing the
Batten marking the position of station mold 1 on the body plan.
Since the weather can be unpredictable at this time of year, there are other things we can be working on: spec’ing the sail plans, procuring materials, and specifying colors. We have received the bulk of the plywood we’ll need, and are now getting in the other materials we’ll use – hardwood and softwood lumber, brass half-oval and flat stock, paint and rope. There is plenty to do!