A Spinnaker for Rowers

The pattern for the model sailboat was for panels 48″ tall and a little over 11″ wide for three or four panels across. For my 14′ Whitehall, I scaled the length up by a factor of 1-2/3 to 80″ and the width by 1-1/4 to 13-1/2″, a proportionally narrower panel for a spinnaker four or five panels across.

I used 4-mil plastic sheeting to make a prototype and drew the pattern on top of sheeting later twice folded over on itself to make four layers.

I assembled the four panels with Gorilla tape to see how the spinnaker would look. I later decided that I could add a fifth panel for more sail area and still have the sail set well.

The cloth, whether the spinnaker cloth I used or ripstop nylon, needs to be heat-cut to keep the edges from fraying. A wooden template will serve as a guide for the hot knife. I didn’t have any plywood to use for it, so I cobbled together some 3/8″ boards.

A piece of 3/4″ plywood served as a work surface for cutting the fabric. A pencil soldering iron with a small ball point works well as a hot knife. Mine is a Weller 25-watt iron, sold in a woodburning kit (WSB25WB) with 10 different tips. It has enough heat to cut the lightweight fabric and seal the edges without excessive melting.

With the cloth clamped tight on a plywood work surface, the template is set on top for hot-knife cutting.

After making the first cut, I moved the template over 1/2″ to provide a seam allowance (I traced along the template with a chalk pencil to mark the allowance). A couple of weights helped to keep the template from shifting while the heat cutting was being done.

After the panels are taped together, a batten sprung along the foot of the sail provided a guide for cutting a smooth arc.

After I had taken this photograph, I decided on a fifth panel, inserted it in the middle, and faired its bottom end in with the curve of the foot. With the foot cut, the spinnaker is ready for sewing.

The panels are sewn together with double-stick tape and two rows of zigzag stitching. The edges are covered with folded 1-1/2″ fabric tape. If rolls of the spinnaker cloth or rip-stop nylon like the one here aren’t readily available, you can heat-cut strips from the fabric leftover after cutting the spinnaker panels

Each of the three corners of the sail get sewn-on patches before the edge tape is applied. Webbing creates loops for attachment points.

To prevent the bag from being pulled off by the spinnaker, it is cinched tight around the base of the blade and its draw cord gets tied tightly at the oar’s throat.

The bag that fits the oar blade also serves for stowing the spinnaker: the head of the sail is sewn into the bottom of the bag. A loop of webbing provides an attachment point for the spinnaker when used with other masts.

I also sewed a bag for the straight-bladed oars I made for my dory. A webbing loop at the top is fitted with a spring hook that clips into the loop at the head of the spinnaker. The long loops of webbing at the bottom were initially for shrouds (a failed experiment). Smaller loops would be fine for attachment points for a line tied around the throat of the oar to keep the bag in place.

With an oar in the mast partners, the spinnaker sets nicely and provides enjoyable downwind runs.

A second oar serves as a rudder. I added an oarlock, set to starboard on the transom, for the purpose. A line tethers the oar to the boat to keep it from going astray if it slips from the lock. With my weight in the stern and the spinnaker pulling at the bow, the boat tracks well without needing any steering, so the oar can trail with the back of the blade skimming on the water. I rotated the blade to face the side I wasn’t to steer to when I needed to change course.

The spinnaker has also been a pleasure to use on the tandem canoe with the bow paddler holding a painter’s telescoping extension pole as a mast and the stern paddler in charge of the sheets.