How to Make a Keystone Cushion for a V-Berth

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Create a comfortable double bed in your v-berth by adding a keystone filler cushion. This small, irregularly shaped cushion may look tricky to make, but we're going to break down the steps for you to make it easy to pattern and sew. If you need to make all new cushions for your v-berth, check out our "How to Make V-Berth Cushions" post (#200620XHT).

Video Chapters:

Patterning — 0:21 min.
Cutting Foam — 1:19 min.
Patterning Top & Bottom Plate — 4:57 min.
Cutting & Sewing Boxing — 7:49 min.
Creating Zipper Plaque — 12:52 min.
Sewing Boxing to Plates — 18:35 min.
Inserting Foam — 20:41 min.
Materials List — 22:15 min.

Materials List:

Marine Upholstery Fabric
Dura-Skrim^® Patterning Material 74" – #103134
CushionRite^® Dry Fast Antimicrobial Foam (Medium) – #124203
Cushion Underlining Beige 54" Fabric – #103934 (Optional)
PremoBond^® Tex 70 (V-69) White UV Bonded Polyester Thread 4 oz. – #124738
YKK^® #5 White Continuous Coil Zipper Chain – #104387
YKK^® #5 White Style C Single Non-Locking Metal Zipper Pull (Coil Chain) – #104333

Tools List:

Sailrite^® Blade Foam Cutter #121244
Sailrite^® Edge Hotknife #103800
Deluxe Magnetic Sewing Guide #103597
Seam Ripper Deluxe #18104
Sewing machine
Marker
Tape measure
Yardstick
Scissors
Pencil

How to Make a Keystone Cushion for a Boats V Berth Video 2 — How to Make a Keystone Cushion for a Boat's V-Berth - Video 2

The keystone cushion we made for our Islander 37 sailboat is a trapezoid shape, which is pretty common, but yours might be a different shape depending on your boat’s v-berth configuration. Our keystone cushion sits in its own tray with trim board between it and the main v-berth cushions. If you have a similar setup, you’ll want to add extra width to the top of your foam so the filler cushion will be flush with the main cushions. To do this, measure the width of the filler board and add that width to the top of the foam width measurement. The end result will be a cushion with an angled edge.

The key to making a great-fitting keystone cushion is careful patterning and attention to detail. In the video, we break down the patterning steps slowly with calculations so you can get the best fit possible for your filler cushion. When patterning your fabric, be sure to take into consideration any designs on the fabric. You’ll see we were careful to match up the stripes on the fabric with the existing v-berth cushions for a cleaner look.

How to Make a Keystone Cushion for a Boats V Berth Video 3 — How to Make a Keystone Cushion for a Boat's V-Berth - Video 3

In this video you will learn how to make a pattern for your filler cushion, cut the foam to size, pattern the top and bottom plates, add a zipper, and sew your cushion.

Do you have a filler cushion in your v-berth? Have you ever re-covered it? Share your tips and advice with us in the comments!