Monday, May 30, 2011

A very clever bug filter

Steve and Lulu on s/v Siempre Sabado have a perfect example of a Small Boat Project:
  • It is easy to do
  • It is inexpensive
  • It is clever
  • It solves a real problem
  • And it replaces an expensive "marine" solution
I love it!
Since we're planning to spend our summer further north in the Sea of Cortez, we've been advised by many seasoned cruisers that we need adequate bug screens. Besides mosquitoes and bobos, we need to be able to keep bees and jejenes (no-see-ums) out of our living spaces. Lulu made a nice screen for our forward hatch and also included a screen in the wind scoop she made. She's currently working on the design for a screen for our companionway. We've been stymied, however, by trying to come up with a way to screen our round portholes.

We've tossed around a lot of ideas and even tried a couple. The simplest seemed to be to just use long cable ties to attach screen to the outside of the ports. Problem was, there's only a very small lip to attach to and it's hard to get the screens on, especially on the ports that have the PortVisors on them. And, the end product looked ugly as all get-out.

Some round ports are made for screens and have a little groove around the inside that a screen attached to a sort of wire snap-ring fits into. However, we don't have those grooves. I thought that the best remedy was to come up with something similar but flat, instead of round like a wire. Something that could be made smaller to fit into the opening and then would expand, holding the screen material in place. Sure, great idea, but what the heck can I use to do it?

I thought I'd hit on the perfect solution when we bought a mini-blind that we could cannibalize for the slats. Seemed like the slats would have just the right amount of spring to do the job. They didn't. The problem with them was that they were so thin that, when I tried to form one into a circle, it wouldn't stay circular but rather would bend into a misshapen triangle.

I toyed with the idea of having some sort of flat snap ring made out of metal, maybe stainless steel. Of course, I'd have to come up with a clear drawing of what I wanted but that shouldn't be too hard, should it? This looked like the most promising idea yet.

Then, one night it came to me. I got up and measured the inside diameter of the ports: 6" and 4". What if I got some 6" and 4" plastic pipe? The outside diameter of the pipe would be a little larger than 6" and 4" so. if I cut it, removed a little chunk and then pressed the ends together, it should fit inside the port and, when released, it's springiness should make it expand out to fit snugly. Yes?

Yesterday, I got 2 short pieces of 6" and 4" plastic sewer pipe and proceeded to saw rings 3/4"-1" in width.

Then, I cut through the edge of the ring but, instead of removing a chunk, I instead heated the pipe and bent the ends down, forming ears that could be pinched together to reduce the size of the ring for insertion or removal.

Lulu sanded the edges so they wouldn't snag the plastic screen.

Attached the screen using double-sided tape and then trimmed it to fit.

Squeezed the tabs together and tried her on for size:

Obviously the screen in these photos is not fine enough to keep jejenes out. But we didn't want to have super-fine screen in all the time as it severely restricts airflow. So, the plan is, when we reach no-see-um country, we'll simply lay a piece of the super-fine mesh screen over the existing screen and snap the ring back in place without taping the screen to the ring. That way it's still very removable.

Ahhh... One less thing to lie awake at night trying to figure out.

Cost of 2 pieces of pipe: 40 pesos (about $3.20)
Cost of screen: free at a boater's swap meet
Cost of tape: ?? we already had some on hand but will have to buy more.

And the beauty is, I still have enough pipe left to make at least another dozen frames for both sizes of portholes.

1 comment:

  1. This is BRILLIANT! Could probably work for the dorade vent holes too.


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