Bobbins and Walking Feet

Ultrafeed Sailrite sewing machine
Ultrafeed Sailrite sewing machine
The walking feet and needle of an Ultrafeed Sailrite sewing machine.

A look at sewing machines for voyagers

A reliable semi-industrial sewing machine suitable for shipboard sewing projects can be a smart investment. Although not inexpensive, these machines can pay for themselves after a few projects. A boat owner can effect simple canvas repairs — e.g., patching a ripped sail cover — as well as moving on to more complex DIY projects. One should never forget that even the best machine in the world won’t turn a beginner into a Betsy Ross. A good machine designed for the job can take the edge off the learning curve, however.

Many different companies market heavy-duty sewing machines that are more powerful and versatile than standard home models. Some are sold as portables, while others are permanently mounted on large sewing tables. These machines are designed to punch through layers of heavy fabric without skipping or faltering. 

Boat owner Kim Randall, who has been sewing since a child, learned this a few years back when she tried using her trustworthy home machine to do work for the family 36-foot Gulf Star. “My home machine just wasn’t strong enough to handle the big jobs I was doing,” said Randall. “And the machine wasn’t equipped with a standard walking foot. It had a walking foot attachment but it didn’t work efficiently. I had to buy a walking foot sewing machine.” The walking foot, a bit of engineering genius, allows the fabric being sewn to be held down and pushed along at the same time. For marine work a walking foot is essential for sewing multiple layers of fabric while keeping their edges in place. A walking foot is not standard equipment in a home sewing machine.

All machines sew the same locking stitch, going both forward and reverse. More expensive machines will also sew a zig-zag stitch where the needle moves not only back and  forth but sideways as well. Jim Grant, vice-president of Sailrite (, a family-owned business since 1969 that is “an online supplier to the sewing marketplace with marine roots,” suggests that unless one is doing sail repair work, a straight stitch machine will suffice. According to Grant, straight stitch machines “are more bulletproof and need less timing adjustment.” Although that may be true, Randall says that the zig-zag capability on her sewing machine is indispensable for mending and adds to the range of projects she does.

Bobbins: A sewing machine sews as thread is fed into the needle from a spool on top, engaging the thread from a bobbin under the needle plate. Bobbins made of plastic or metal are truncated cylinders that have to be rewound when they run out of thread. Most sewing machine users keep a number of already pre-wound bobbins on hand, so they don’t have to stop work to rewind.  Some sewing machine companies advertise the advantage of a larger bobbin, but larger bobbins are not necessarily better

Thread: The classification of thread is a confusing hodgepodge of various terms and definitions. The big three classifications are TEX (T), Denier Count (TD or D) and Commercial (V). For marine application we are only concerned with V. This classification ranges from V30 to V554. The higher the V number the heavier the thread. The weight of the thread is measured in grams per 1,000 meters of thread. The consensus for marine work that has to stand up in the weather is a V92 polyester thread, usually sold in 16-ounce spools. It has high strength, low stretch, with high abrasion resistance.

  Even though it is still referred to as “canvas work,” a mariner would be hard-pressed locating any canvas aboard a modern boat. Canvas is old school, a natural cotton fiber technically defined as “a double warp, single weft fabric made of hemp, flax, or cotton fibers.” In its day, canvas was the “go-to” material used for everything from sails, to hatch covers to shrouds for expired seamen. It is a great fabric though with several major drawbacks. When it gets wet, it stretches, losing its shape. It is also subject to mildew and rot. 

The new “canvas” is a synthetic fiber either of acrylic or polyester. It is colorfast, water-resistant, keeps its shape and is only minimally affected by moisture. The best known of these fabrics is Sunbrella an acrylic (plastic) cloth perfectly suited for the marine environment. It is solution dyed, meaning the color is inherent in the fabric. Sunbrella is sold at prices of $25 to $30 a yard in standard widths of 46, 54, 60, and now recently 80 inches. Being a plastic material Sunbrella frays when cut with scissors, so the preferred method is to use a hot knife which cuts and seals the edges. The 46- and 60-inch widths are used primarily for boat projects. The 54-inch is used mostly for upholstery. 

Needles: According to Grant, there are more than 4,000 needle classifications throughout the world. One well known German needle company, Schmetz, organized a classification of needles called CANU which stands for Catalogue Numbers. The system classifies needles according to length and thickness. The lower the CANU number the smaller the needle. Information concerning needle size will come with the machine manual or can probably be found on the Internet. Grant says that folks can call Sailrite if they have an old sewing machine and don’t know the right needle to use. “We have all the Singer Manuals and can find the right needle for the specific machine.” If the wrong needle is used in a machine, either it won’t be long enough to pick up the bobbin thread or it will be so long it will damage the bobbin case. 

If mariners are interested in gathering more information on sewing machines, fabric, needles, thread, etc. they could do no better than contacting Sailrite online. It is a voyager-friendly business and will answer all sorts of questions. I have been using one of their machines and asking them questions since 2012 when I first began sewing. Of the four sailors I spoke with for this article, all own Sailrite sewing machines.

Contributing editor David Berson writes the nav problem column for Ocean Navigator. He is a co-owner of the electric launch Glory, based in Greenport, NY.