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Making a Sail Cover for
my Tanzer 22

My old sail cover had given up the ghost at the end of the season. The fabric was tearing, all the seams were coming apart an many of the fasteners had long ago disappeared.

The old sail cover did not in fact cover the sail well at all. The top did not fit in nor was it fat enough to fit the sail in at the corner of the mast and the boom.

I still had some fabric left over from the cockpit cushion making and used this to make a new sail cover. It is UV protected Awning material made from polyester with a fairly tight weave. I don't think it is absolutely waterproof but it sheds water.

Making a pattern for a new tanzer sail cover

I had measured my boat before putting it away for the winter and I had the old sail cover. This would allow me to make a new pattern for my Sail cover.

After ripping the remaining seams open on the old sail cover I used this as a base for the new cover.

I knew the Sail Cover would have to be higher, longer and fatter in the middle section. I used tailor's chalk to draw the new outline, then added another 5/8 inch for seam allowance. The middle seam would be turned over and top stitched so it needed more. I ended up making true french seams for the top. Very solid and reliable since it is stitched 3 times. This is probably overkill.

Making a pattern for a new tanzer sail cover

Using my measurements I chalked on the larger size making sure there was enough for the seams.

I had to flatten out the old cover since it had stretched out. I pinned the old cover on the fabric with the bottom on a straight line and the part that goes up the mast at right angle.

I checked my figures and made sure I had added enough extra, plus the seam allowances and area for the fasteners.

DIY Sail Cover first piece is cut.DIY Sail Cover second piece.

The first side is cut.

After unpinning the old sail cover I turned the piece up side down and pinned it on the fabric making sure that it was nice and straight. I had to reverse the pieces because my fabric has a very definite right and wrong side. The 2 pieces are mirror images of each other. If the fabric had been the same on both sides then it would not have made any difference.

Sail Cover is cut out

At this point the quality inspectors noticed I was doing something interesting and offered to help. This is her stubborn "I'm not mooving" face.

The 2 pieces are now cut out and Tilley has inspected. She is definitely NOT moving. She has hunkered down her 7 pounds of solid attitude!

DIY Sail Cover back seam

The top seam is pinned and started. I'm using heavy duty sail thread. It's thick polyester with UV coating. I find that using large needles work better and high quality needles make a huge difference. This thread comes from Sailrite.

Winston takes over for the sewing inspection.

DIY Sail Cover seam diagram. Detail of seam

I'm making a full French seam that is further stitched down flat. That gives 3 layers of stitching. The seam is thick but solid. It has no exposed edges on either side. Tilley takes over sewing.

Detail of seam

Pinning the bottom and the side that will go up the mast. Usually on long straight seams I don't bother pinning but in this fabric any crooked bits show up because of the stripes. it's safer to pin long seams. Also it's easier to control the feed of the sewing machine if I don't have to worry about it going through evenly. It does take slightly longer but sewing is faster.

cover is sewn

After folding over and sewing the edges that will have the twist lock fasteners, I folded over the 2 edges at the top of the mast part and at the end of the boom. Just turned over and stitched. I did double stitches on all the edges.

After this photo I pressed the fabric using a warm iron and a wet cloth. It flattened nicely and looks good.

The original sailcover had a small flap of fabric running the length of the mast seam. It presumably keeps rain off the inside. I included that using a scrap of material. I just sewed it in while doing the vertical seam.


I had carefully removed what fasteners remained on the old cover and found that they were still in good condition. The backing plates and prongs had to be straightened but that proved to be easy enough.

I did not have enough so I ordered some more from Sailrite. They also have good video on how to install them if you need it. I used an old screw driver I had ground down and sharpened to cut the slots where the small taps fit through. I had a piece of wood as backing. It worked very well with no particular trouble. I'm not worried about them failing because even if they do I will just replace them.


I used fittings from an old knap sack to make a couple of straps. I plan to use them around the boat. If the sail cover needs to be tighter at the mast area then I will use a strap to tighten the cover. I had waterproofing spray that is used for furniture and I sprayed the cover with this. Help it shed water better.

boat tiller cover

I'm just waiting now for the fasteners to be delivered and the cover will be complete. While I'm waiting, I put together a quick boat tiller cover. I used scraps from the sail cover and a fastener from the old knap sack. I had bought a nice new tiler and was worried that it would get damaged in the sun.

Fasteners came quickly and I was able to finish the sail cover. I'm all set.

Sail cover on the sails

We launched early may and I put up the mast and installed the sails. The new sail cover fits perfectly. The straps that were installed at the mast and end of the boom work well to keep water from coming in. I'm happy!

UPDATE: 2 years later the sail cover is beginning to rip. I'm thinking that the uv coating was not particularly impressive. I've made a new cover using Sunbrella and it is holding up very well. You get what you pay for. The larger cover fits the sail much better too. Here is a source for Sunbrella. Sunbrella Marine Grade - 6001-0000 Pacific Blue Fabric The better grade is Marine grade.

email me if you find mistakes. I'm better at boatmaking than spelling! I'll fix them and we'll all benefit: Christine