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SJ23 Forward Hatch Bug Screen.
 

I have long wanted to replace Panache's forward hatch bug screen as it has seen better days years ago.  I curse it every time I try to stick it to the Velcro under the hatch for sleeping onboard.  The problem is that it was folded for a very long time and because of that a permanent crease has set in the screen.  That crease eventually cracked, creating a highway for bugs to zoom through.  And boy do they find me.  This is the primary reason why the replacement screen will be rolled up for storage.  It will be stuck to the underside of the hatch to keep me away from the bugs while the bugs stay on their side.  One thing is for certain, anything that keeps those #$%^& skeeters out is a solution to me.  I think they make wonderful bird food, don't you agree? 

  DESIGN

The new design has to be quick to set in place or release for escape during an emergency.  Always keep the emergency escape thingy in mind!  The screen will have a border of Sunbrella to protect the mesh and to which the Velcro will be sewn.  The ceiling Velcro will be stuck to the bottom of the convex channel that surrounds the opening.  To deploy it, the screen will be rolled out along the underside of the SJ23 hatch, mating Velcro to Velcro. 

  OTHER DESIGNS

• I have seen a very nice (and expensive) bug screen that was set in a track attached to the cabin ceiling.  It was very slick to use as you only had to slide the bug screen across the open hatch to keep the bugs out.  Slide it the other way and there was reflective surface to block the sun, keep the inside cool.  Unfortunately the shape and size of the SJ23 ceiling isn't conducive to this design and I'm not about to fabricate a curved frame. 

• I wouldn't recommend laying a loose screen on top of the open hatch, even if the perimeter of the screen is weighed down with a sand or lead pellet filled hem.  You would think the weight would keep the screen in place but it seldom survives the initial blow that heralds a decent dump of rain.  Besides being difficult to lay across the open hatch, the edge could wick water into the cabin once the deluge soaks the deck.  That being the case you will be pulling a wet screen inside, over your dry bedding.  I hardly think this is what anybody has in mind. 

There are probably other variations of a hatch screen, but sticking one to the cabin ceiling with Velcro is the simplest design I've seen.  If it starts to rain, all I have to do is pull the corner of the screen down and lower the hatch.  Not having to go outside is a huge advantage to keeping the mosquitoes outside.  However, this screen CANNOT stop a  swarm of meat eating no-see-ums.  That being the case I will bite the bullet and light up a bug repellent coil. 

  CONSTRUCTION

Fig 1 - Panache's new bug screen is 24" square with a 2" wide protective hem of Sunbrella to sew the Velcro to.  This dimension nicely overlaps the 23" square ridge around the bottom of the hatch to which the 1" wide adhesive backed Velcro will be stuck.  Seal all edges of cut Sunbrella with a hot knife.  Fold each 4" wide strip of Sunbrella into a 2" wide hem and slip it over a side, tucking the screen in to full depth.  Run a straight stitch down the hem to secure it so you can attach and sew the other three sides.  The corners of the hems are cross lapped and the Velcro is mitre cut for strength.  The finished screen is shown below. 

I also included a pull tab at each corner to remove the bug screen as I've always found it difficult to remove my original screen without rearing off the delicate strip of 1/4" wide Velcro.  Yah gotta be quick when it comes to beating a mosquito.  Why yellow pull tabs?  So I can see or feel them at night to close the hatch, without switching on a light that attracts bugs.

Fig 2 - I chose to sew the loop side (soft) of the Velcro to the back side of the screen since it rolls up easier than the hook (hard) side.  With the hook side glued to the underside of the hatch I'll have to be careful when crawling onto the forward berth so I don't snag wool from my sweater.  I hate the sight of fluff stuck to Velcro.  It looks so tacky.

Fig 3 - Velcro attached to the ceiling.  Given that the cabin may occasionally have high moisture I washed the ceiling with acetone so the Velcro has a fighting chance to stay stuck.  This technique almost always guarantees success.

Fig 4 - And finally the bug screen on the ceiling, albeit lightly applied as the Velcro adhesive hasn't set yet.  It is so much easier to place it evenly with the roller and remove it with the pull tabs.  I'm going to enjoy some bug free nights this summer.

Fig 5 - To protect the screen during storage I roll it up around a 2" tube of ABS to limit the minimum bending radius.  The tube also makes it easy to stuff the screen into its nylon storage bag, with the no damage.  For convenience it will be tucked behind a fiddle at the forward berth where it will be used.

The Sailrite Ultrafeed LSZ-1 sewing machine sure came in handy for this project.
 

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