Half-square triangles
Sailboat
A boat under sail: a large feature triangle for the sail built from half-square triangles, an accent trapezoid hull across the bottom, and background for sky and water. Piece the sail HSTs first, then the hull row.
Cut list
What to cut for one 12 inch finished block. A quarter inch seam allowance is already in every size.
Feature
- 2 squares
- 3⅞"Cut once on the diagonal, layered with the background fabric. Each square makes 2 triangles. This block uses 3.
- 3 squares
- 3½"
Accent
- 1 square
- 3⅞"Cut once on the diagonal, layered with the background fabric. Each square makes 2 triangles.
- 2 squares
- 3½"
Background
- 2 squares
- 3⅞"Cut once on the diagonal, layered with the feature fabric. Each square makes 2 triangles. This block uses 3.
- 1 square
- 3⅞"Cut once on the diagonal, layered with the accent fabric. Each square makes 2 triangles.
- 6 squares
- 3½"
By region
| Region | Fabric | Units | Cut from |
|---|---|---|---|
| Feature 1 | Feature | 1 | 3½" |
| Feature 2 | Feature | 1 | 3½" |
| Feature 3 | Feature | 1 | 3⅞" square, cut once on the diagonal |
| Background 1 | Background | 1 | 3⅞" square, cut once on the diagonal |
| Background 2 | Background | 1 | 3½" |
| Feature 4 | Feature | 1 | 3½" |
| Feature 5 | Feature | 1 | 3⅞" square, cut once on the diagonal |
| Background 3 | Background | 1 | 3⅞" square, cut once on the diagonal |
| Background 4 | Background | 1 | 3½" |
| Background 5 | Background | 1 | 3½" |
| Feature 6 | Feature | 1 | 3⅞" square, cut once on the diagonal |
| Background 6 | Background | 1 | 3⅞" square, cut once on the diagonal |
| Background 7 | Background | 1 | 3½" |
| Background 8 | Background | 1 | 3½" |
| Background 9 | Background | 1 | 3½" |
| Accent 1 | Accent | 1 | 3⅞" square, cut once on the diagonal |
| Background 10 | Background | 1 | 3⅞" square, cut once on the diagonal |
| Accent 2 | Accent | 1 | 3½" |
| Accent 3 | Accent | 1 | 3½" |
| Accent 4 | Accent | 1 | 3⅞" square, cut once on the diagonal |
| Background 11 | Background | 1 | 3⅞" square, cut once on the diagonal |
How it goes together
- Step 1
Cut your pieces
Cut the pieces in the cut list. The sizes are for a 12 inch finished Sailboat block and already include a quarter inch seam allowance.
- Step 2
Make the half-square triangle units
Sew each pair of triangles along its long edge and press toward the darker fabric. Trim every unit to size before you join it.
- Step 3
Assemble the block
Join the units into rows, then join the rows. Press as you go and square the finished block to size.
Read more
Color value vs hue in quilts
Value is how light or dark a color is. Hue is what we usually call “the color itself.” In quilts, value carries the design — hue carries the mood.
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Quilt block families, explained
Most quilt blocks belong to one of six families — Patchwork, Half-square triangles, Flying geese, Stars, Curves, and Hexagons. Each family is a way of piecing fabric together.
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The quilter’s seam allowance, explained
A seam allowance is the strip of fabric between the seam and the raw edge. Quilters work in a standard 1/4 inch — and getting it right is the difference between a top that finishes flat and one that fights you.
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Try the Sailboat on a real layout.
Open it on the Design Wall. Try a few colors, see the math, change your mind.