Theyre not for use underway, but hood-shaped fabric air scoops can be a godsend when theres but a slight breeze stirring the heat.
Theres no secret to their effectiveness. Theyre just big. They grab a lot of breeze and build it into a bit of wind to funnel belowdecks.
Sailmakers have been known to cut and stitch custom versions of these devices. However, there are apparently only four ready-mades on the market.
Davis Instruments makes the original Windscoop, which lists for $45 and discounts for $33.
Made in China of nylon, reinforced where needed and double-stitched or zig-zagged, the Windscoop is advertised as being 30″ wide and 67″ tall, but that height measurement includes the triangular piece on top. It still intercepts a lot of air with a frontal area that measures 30″ x 50″. Thats more than 10 square feet of exposed sail.
In a prior PS test, with 5 knots of air over the deck, the Windscoop directed air below at between 8 and 12 knots.
The Windscoop is fairly easy to rig, hoisted with a single overhead line and held down in a hatch by a wooden dowel into which are screwed two brass eye hooks. The dowels length usually can be trimmed when youve settled on a rigging system. If done craftily, with just the right tension, the scoop can be induced to swing with the wind. Owners sometimes pad the dowel to reduce the clattering. The bottom of the Windscoop contains another batten to prevent the back edge from curling.
(Davis used to make a more complicated scoop called a Foresquare. It was clever…in theory. It had a four-element scoop with two dowels to position the flat top and supposedly was omni-directional, which would be helpful for boats stationary at a dock. Instead, it was just a lot of fabric. Davis gave it up. Also no longer made, because there are so many sizes of hatches, is the Hatch Scoop made by Creative Marine. A combination scoop and screen, it required custom fitting.)
Windscoops competition now is from the French firm, Plastimo, which calls its version the Ventilating Sail and West Marine, which offers two fabric devices-the Down-the-Hatch and the Breeze Booster.
Both the Plastimo and West Marines Down-the-Hatch are like the Windscoop in that each has a sewn-in batten at the top, are rigged on an overhead line and secured with the top tilted to windward with a piece of small stuff led to the forestay. The three have quite different methods of securing the bottom in the hatch.
The Plastimo version is made of what appears to be less substantial material. It has two grommets in tabs sewed to the bottom leading corners, which are supposed to fit over two plastic hooks attached with two screws (not furnished) somewhere on the hatch or overhead. If you wish to rig it in a different direction, additional hooks placed in other positions would be needed.
There is no bottom batten and the entire device does not take a good firm shape.
If you buy the Plastimo, the first step would be to buy a dowel and brass eye hooks to rig it like a Windscoop. There is not much you can do about the wretched sewing.
If you can get it rigged and working, the Plastimo, 26″ wide and 54″ tall, with a frontal area of 9.75 square feet, should move almost as much air as the Windscoop. But it doesn’t, mostly because the shoulders do not open in a good position and the bottom end flaps.
You also would need to make or buy a long cloth bag; the Plastimo comes in a clear plastic bag that might be intended for stowage but is clearly inferior to those furnished with the other scoops.
List price is $66.38.
West Marines Down-the-Hatch is described in the West catalog as 4′ x 6′. Actually, its frontal area measures about 31″ x 50″, nearly identical to the Windscoop. It also has a lower batten to keep the bottom back edge straight.
The material and sewing (lock and chain stitching) is equal to the Windscoop.
But instead of using the Windscoops dowel, the four bottom corners of the Down-the-Hatch must be secured by long ties with adjustable cords with plastic snap hooks. If theres nothing to which the ties can be secured, West suggests that you install screw eyes or small eye straps.
Securing the bottom end of this Taiwan knockoff of the Chinese-made Windscoop is easier than with the Plastimo, but unless a loose dowel is used the Down-the-Hatch will not weathercock like the Windscoop.
The bag in which it stows is only 30″ long (compared with 48″ for the Windscoop), but thats only because theres no dowel.
The Down-the-Hatch sells for $30. Unless youre interested in saving $3, buy the Windscoop.
Compared with the three long cowls described above, the Breeze Booster is quite different. Its something like a pup tent.
Slipped over a hatch (opened 90), it makes a hood shaped by flexible plastic inserts bent into shape by a pair of ties led below and secured to a wooden stick. For different types of hatches, the lower back edges width can be adjusted with metal snaps, which are properly made of stainless and brass.
The result is a nicely tensioned fabric cowl with its lower back corners held by the hatch and its forward face held open in a vertical plane by stiff plastic struts. The sewing is well-done.
This apparatus, which is not as complicated as it sounds, initially requires some patient tinkering. However, once set up for a given hatch (with the strings knotted and snaps right), it can be rigged quickly.
Although not as large as the others, the Breeze Boosters principal advantages are that it can be oriented in any direction, remains open in any breeze and requires no overhead support. It can, of course, come loose and tumble off the boat, so a lanyard is a good idea.
Most importantly, it collected and concentrated air a bit better even than the Windscoop. Though a bit smaller in its dimensions, we attributed its excellent performance to its wider, bowed opening and cleaner, curved shape.
Because its far more complicated to make and must have adjustments to fit different styles of hatches, its also more expensive. There are three sizes of the Breeze Booster available, costing from $57 to $70. There is a choice of six different colors. An insect screen is optional.
Enough of this. Off to the boat, with a couple of anemometers. One instrument was the new, very sensitive Skymate anemometer (from Speedtech Instruments, 10413 Deerfoot, Great Falls, VA 22066, 800/760-0004); the other was an older Skywatch Elite, from the same source. The latter was ideal for the purpose because it has a max reading window.
Each air scoop was rigged carefully, per the instructions and tweaked where necessary.
The Breeze Booster is the easiest to rig. Takes but two or three seconds…after you get the hang of it. Of the three hang-it-on-a-halyard versions, the easiest is the Windscoop. The West Marine Down-the-Hatch and Plastimo require fussing about with ties. If one had small brass eyes in the proper places, both would be better but still not as easy as the Breeze Booster and Windscoop.
After each hood was rigged, the breeze across the deck was read and recorded frequently. A series of simultaneous readings from just below the hatch lip (at whatever position the wind seemed greatest) indicated how much the deck-level breeze was amplified by each device.
Averaged and rounded, these readings gave a fair indication of how well each scoop worked. The simple results are contained in the captions under each photo.
The Breeze Booster and Windscoop were best, with the West Down-the-Hatch third and the Plastimo a poor fourth.
The Bottom Line
How do they compare overall?
Message to Plastimo: It shouldnt be that difficult to imitate Windscoop; West Marine did it fairly well.
Message to West Marine: The strings and hooks are okay, but a dowel seems better.
Message to Breeze Booster: Very nice contraption and it stows well.
Message to Davis: Your old Windscoop is a Best Buy but the Breeze Booster just passed you as the best fabric hatch vent.