Bug and Rain Proof Windscoop

Front of windscoop (with Gray)

This hurricane season, our highest priority canvas project was a windscoop for the V berth hatch.  Our design is a modified version of Terry Sargent’s squall proof windscoop as depicted in Jim Grant’s The Complete Canvasworker’s Guide Second Edition.   The idea behind this windscoop is to keep wind flowing into the cabin and water out even during rainstorms.  This is accomplished by means of an interior flap that covers the upper half of the scoop opening when the flap is in the “down” position.  The lower edge of the scoop is angled upwards from the opening to the hatch, thus keeping out any possible airborne wetness.

Our version differs from Terry’s in two major ways.  Terry’s design is basically a tube that rises from the hatch, then turns forward and down towards the opening.  Since our hatch is on an area of deck that is raised above the main deck level, we did not have to make the turn segment to keep the rain out – it simply extends straight from the hatch to the opening.  The other difference is the addition of a bug screen at the hatch opening.

While some of the projects in Grant’s book are described with plans and step by step instructions, the windscoop project is basically a line drawing and a short description of the principles involved.  Cindy spent about a week taking measurements and scratching her head before deciding to draw an exact pattern using Visio.  Using Visio helped a lot, making it possible to figure out measurements for some of the trickier pieces before making embarrassing cutting mistakes.  After making to-scale shapes of all necessary pattern pieces, she typed a checklist of instructions for the whole project.

We decided to use the same yellow Surlast fabric we used for the awning to make the windscoop.  We had a lot of it on the boat already, and we thought it would look nice when both the awning and windscoop were set up together.  Since Surlast is not a particularly stiff material, Cindy stiffened the opening edges and all areas to which fasteners would be attached with 2 inch widths of dacron sail tape (used successfully on the awning).

Windscoop side and rear view

Terry Sargent’s plan did not address how to attach the scoop to the deck.  We decided to use snaps.  The port and starboard sides of the hatch opening have flaps with rows of snaps which correspond to snap bases anchored in the deck.  The forward edge has snaps on its front edge, since it rests against the deck anyway.  The back should not have any strain on it, so it does not have a snap flap.  We can always add one later, if we need to.

Another thing that puzzled Cindy was how to make waterproof seams.  On the awning, it was easy to make flat felled seams wherever two pieces met.  On this project, the outside corner angles where the top met the sides were the critical seams, but she couldn’t use the flat-felled technique on them.  She solved the problem by sewing the sides to the top wrong sides together, and wrapping a strip of Surlast around the raw edges.  Sewing the wrapped seam flat, she hopes she has made a fairly waterproof seal on the areas most likely to leak.

We made a handle on the top of the windscoop out of a length of nylon webbing, box-stitched in place.  The purpose of the handle is to be a halyard attachment point.  The halyard keeps the top of the scoop up, but also raises the center to keep any rainwater from pooling.  The shape of the back is formed by the raised window.  The front holds its shape by lines led forward from grommets at the top and bottom edges.  Battens would give it a more upright, square shape, but would make it more difficult to store.  An easy way to do this would be to cut lengths of PVC tubing and install them on the exterior of the windscoop opening by running line through the tubing and the forward grommets.  We will keep battens in mind for a possible future enhancement.

The rain flap is held in place with snaps.  It may be set in an up or down position by reaching inside the hatch from the V-berth.

Like the awning, all of the seams were sewn with UV resistant gore-tex profilen thread, so we hope the windscoop will give us years and years of use.

Cindy and Gray