Boat Necks
A boat neckline is a wide but shallow neckline. This particular neckline intersects the hollows of the shoulder slope, so that’s the only pattern accommodation needed beyond redrawing the neckline. I’m going to show you how to transform a round neckline into a boat neck, using the Bo top as an example.
Note: If you are working with a top like Orlando, which already has a pretty wide neckline, you can skip contouring the shoulder seam and just redraw the neckline.
Step 01: Remove the seam allowance at the shoulder seam and neckline on both the front and back pieces.

Step 02: Then, determine the desired width and depth of your neckline. The easiest way to do this is to hold the cut pattern piece against your body. Align the center front of the pattern piece with the centerline of your body and align the shoulder seams along your shoulders. Use a ruler to measure the desired width and depth of your neckline. Depending on your pattern and preferences, you may choose to reduce the neckline width or leave it as is.
In this example, I raised it by 3” and widened by 1”.

Step 03: Lay your pattern piece on your working surface and tape a piece of pattern paper underneath the existing neckline if necessary. Use a ruler to mark the desired neckline at the shoulder and center front. Reduce the neckline at the shoulder by 1/4”, then redraw the shoulder seam.

To avoid creating an unintentional V-neck, you’ll want to square off the center front neckline. To do this, use a clear ruler to make the centermost portion of your neckline perpendicular to the center front fold line. About 1/2” should do the trick. Then, redraw the neckline with a French curve.

Step 04: Repeat these steps for the back neckline, making sure that the shoulder seam matches the front piece.

Step 05: Add seam allowance then cut it all out.
If you need any help, be sure to share in the Community.
Learn to Change a Neckline