HighWindProof Solar BunkEndCover Redesign:
the pix
A detailed commentary follows below. Meanwhile, here are captions for the column of pix to the right:

• King bunk cover installed

• Double bunk cover installed

• Inside view from king bunk

• Battens laid out on cover

• Batten 2/3 way into sleeve with bonnet and cinch lines hanging free

• Uncinched batten inside king bunk sleeve shows the gap; cinching induces camber and stiffness

• Batten cinch lines and horn cleat scheme a) unstowed and b) cinched

• Bonnet cinch adjustable bungee and hook end

Of all the mods and improvements I've made to the camper, none has proceeded with so much uncertainty as attempting to windproof the solar bunk end covers. The covers are important and valuable to me because the effectively reduce the temperature inside the bunk ends by a massive amount. Altho I've not measured temperatures, when deployed sans shade without the covers it's far too hot to inhabit the bunks and the shepard poles are burning, too hot to touch even momentarily. With the covers the poles are just poles, not branding irons, and one can enjoy the bunk ends for a rest after a very hard windsurfing session. Thus, if one insists on camping in shadeless, high-wind (25-40 mph sustained plus gusts) environment and wants the benefit the covers provide, one must assure they will stay on and not shred ("shredding" is a term better saved for very fast sailing).

I'm given to understand that the reason covers like these are not already intrinsic to the campers as we buy them off the lot is that the tenting has a significantly longer expected lifespan, thus the manufacturers don't want to degrade that by permanently installing solar reflective material. There are two basic approaches to high-wind-proofing a sheet of material laid atop the tenting: marry the edges or stiffen them. Marrying is, in my opinion, invasive to the camper: Spirit Deer (active on irv2.com) suggests sewing zippers to the tenting and the covers. This could potentially also allow the covers to simply stow as the camper is popped down. Alternatively, one could have made and affixed little awning-type bags into which the covers might roll up after unzipping them. When the covers are married there's no way for air to get between them and lift the upper surface. It's an intriguing idea requiring turning your tenting over to a tent repair shop. I'd rather not.

I should say at this point that as delivered by Popup Gizmos, the provided clips perform very well in low wind environments typical of wooded campgrounds. Increasing the number of clips used to fasten the covers, leaving ~6" gaps AND cinching the outer edge (I call it the bonnet) with a tautly pulled line secured under the "chin" of the bunk end, can perform adequately in 20-30mph winds.

(continued below)

HighWindProof Solar BunkEndCover Redesign Commentary
I opted to stiffen the edges of these covers...make it hard, if not impossible, for the wind to pry under and lift the cover. Windsurf sails use long, tapering fiberglass rods called battens to help keep their shape. Battens are inserted into sleeves. Thus, I needed to add batten sleeves to the outer edges of the covers and select a method of cinching them to the bunk ends. (note: I had already implemented secure, fast-deploying fastening systems for the roof and bonnet sides of each cover; the roof edge is velcroed to vinyl siding Jchannel which slips over the bulb seal and stays in place, anchored additionally with some velcro on the backside, and the bonnet edge has been modified with a sewn-on webbing channel through which runs a line. The line is pulled taut and fastened under the bunk end.

I sewed 2" wide polypropylene webbing lengths along the edges, shaping the fabric to provide some slack in the resulting tunnel so the battens, when inserted, wouldn't stress the material. The battens seat in a pocket formed by folding over the webbing on the roof end, and are locked in place by a velcro flap sewn at the bonnet end of each sleeve. Each sleeve is broken into several short sections with gaps in between where one can affix line, webbing, or a ball and chain ;-) to pull the cover down. I opted for line because I could stow it in place and not have a bunch of loose parts to content with. This meets my 'easy to deploy and self-stowing' requirements.

I improved my bonnet lines by replacing bungee, which streches too far too soon under wind load, with 5/32" line. I tied a short length of bungee to each end since I like the notion of some flexibility rather than a fixed length connector. I can control the amount of pull by simply tying knots in the bungee; one of the accompanying pix shows my current state of 5 knots. The first knot also serves to lock the hook collar in place.

The batten cinch lines are of the same cord, although I may replace them with black parachute cord. White recedes from view from inside the camper and from outside with the tent flaps up; black recedes from view from outside with the tenting down since the screen material is dark. Pick your poison; there's no getting around the fact that this mod, unlike any other I've engaged in making, does not enhance the appearance of the camper—quite the contrary.

The cinch lines are looped and knotted at the top; as you slip a batten in its sleeve you also thread it through each cinch line's loop. The lines conveniently stow below the bunks, each line wrapped around its own horn cleat. The bottom end of each line is knotted so they cannot slide through the center hole of the cleat; thus they are 'permanently' installed. After pulling out the bunk ends you run around unravelling all the cinch lines and let them hang toward the ground. There they lay, in place, for you to pick their loop end up when threading the battens.

Cinch lines are tied off to the horn cleats with a series of underhand loops that lock each loop as it is made. Alternating side-to-side on the cleat, I make 4 loops to securely fasten each line. It's quickly done by feel once you know the motiions. I tension the cinch lines ever so slightly to induce camber into the batten, pulling it down just past where it would conform to the natural concavity of the tenting.

I installed 3 cinches per king bunk end side, and only one on the double bunk end. I obtained the new generation clip from Popup Gizmos: still small but about twice the gripping power, and install 1 or 2 clips on either side of the small bunk end sides.

I encountered a great many choice points in the sewing and dimensioning of these batten sleeves. I'll mention just a few in this article:
• 2" wide sleeves provide valuable flexibility...when the cover edge folds over the tenting, the clamp jaws contact the covers' edging below and the webbing sleeve material above. Clamps no longer ever directly contact the cover. This is critical to prevent rips and tears should (when) the wind lifts with enough force so that the cover/clamp combination slips off the tenting entirely.
• one needs to allow clearance and not run the battens from end to end. I left ~4" clearance behind the conestoga support tubing and ~1" before the outer edge of the Jchannel. These pix do not yet show the 4x4" webbing reinforcing sandwhich I plan to sew at the outer corners of each cover where they fold over the conestoga tube and get pulled taut by the bonnet cinch.
• use polyester thread and a narrow zigzag stich, quadrupling over several stitches every 1' or so to limit any unravelling.

Used/leftover windsurfing sail battens may be found in bins at windsurfing shops and cost ~$5 apiece.

Stowage

I have found a place to stow all 4 battens securely: on the aluminum shelf behind where the roof seal sits when the roof's down. I've added several velcro sections to capture the ends of the short battens. Due to the door placement on a Cheyenne, the long battens are secured by tucking behind the roof lifter assembly. I stow the rolled up cover/Jchannel assemblies in the hallway. I have added a B hieroglyphic above my stepper door lock (in concert with the 2 W hieroglyphics described elsewhere on this site) to serve as a reminder to myself to double check that the battens have been stowed prior to departing a site.

Ongoing Problems

As I said above, there's much about this mod that's proved troublesome to me. This latency hasn't run out, either. After 18 months' ownership of this, my first RV, I finally got to camp in serious rain. That webbing I used is a sponge. I would not want to stow the rolled up covers in the trailer. Fortunately I was travelling solo and just stowed them in the tow vehicle, placing towels under each end of the rolls to catch the volumes of water dripping out of them. Passengers would have been uncomfortable to say the least. I've since learned that Popup Gizmos uses Sunbrella binding to edge their covers, but I have my work cut out for me to locate a source for cut lengths of the wider material I need for the batten sleeves and bonnet channel in this lighter weight, water resistant material (typical wholesale buys are measured in thousands of feet...).

2005 50mph sustained wind report

I have learned that the SBEC material is very strong. But it can and will rip. I did not engineer the cover mod for system failure—espcially when that system is the camper itself. The short story: while sleeping in the TV due to sustained 50mph winds, the king bunk end support pole bent and broke at the lowest part of the U (a Fleetwood/Coleman design; the pole is now made of steel rather than thin aluminum). I awoke to find the tenting and the covers, with their stiff battens installed, flapping wildly. It's a testament to the cover's strength that it didn't rip all to shreds, or that the batten didn't come through and damage the tenting. Key lesson: reinforcement at key potential stress points. I'm busy sewing webbeing on the underside at these points, and repairing rips with spare cover material.

See this page for a moderate wind (10-20mph) solution.

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