At Hood Canvas, we always precut our pattern blanks to rough size, including any center lines.
Most custom shops T-pin the enclosure pattern to the bottom half of the zipper on the bimini. We prefer to stay-stitch the bottom half of the zippers onto the top of the pattern blanks and make adjustments to the pattern back at the shop and out of the wind. You simply have to zip on all the patterns as soon as you get to the boat and pull tight against any breeze. It makes the patterning process go quickly and easily.
Start by taking your pattern blanks for the two sides and stay-stitch the zippers from the bimini onto the top of the pattern in a straight line. Be sure to mark them port and starboard. Now take the forward and aft pattern blanks that have the curve on them from the “Flip Trace” technique (discussed in the previous article in the March/April issue). You need to stay-stitch those zippers onto the tops of the pattern blanks following the curves.
Now, on the boat with the patterns all zipped on, start with the forward pattern, where it comes down on an angle and tucks under the windshield, creating some difficult angles to deal with. You might want to add some double-stick seam tape to the top edge of the windshield to hold the top half of the pattern in place while dealing with the bottom half.
A couple of things should be noted about this process: first, this method can be used to correct imperfect angles on the forward and aft patterns, as well; second, this method works equally well for hard-top enclosures.
We stitch our keder tape on like we do for zippers, but on a straight line for all four sides and correct angles as necessary.
Note: The large binder seen in the Jan/Feb Shop Techniques article on fabricating enclosures is available for purchase at www.hoodcanvas.com. Mark Hood is available for private consultation and training.