7.09.202 Winching the shutters back on:

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Tuesday 7th 48-65F overcast. 

I fixed the boat winch to the observatory building. Then looped a ratchet strap 3 times around near the top of the shutter. The boat winch hardly noticed the strain on the cable. The first image shows the shutter leaving the ground. 

The winch cable ran smoothly over the top of the dome. Via the slit ribs and top rung of a ladder. Thanks to the doubled, ply ribs the shutters have become far to heavy for one period to lift. I could lift them horizontally but not get them safely inclined to fit over the dome.

I used one ladder and then two. To protect the dome from being scraped by the shutter during the lift. Apart from not being able to see what was happening it all went effortlessly. I paused regularly to walk around the dome to check lifting progress.

Once the shutter was in place I adjusted the bottom support height. To make the shutter concentric and aligned with the dome slit. Some minor adjustments were needed to the shutter bracket angles to correct out-of-vertical ribs.

The drawer slides were 1cm too long. So I bored and sawed a rectangular hole in the outer shutter rib. This allowed the outer, drawer slide section to fit into it when closed. The pair of shutters will now meet in the middle. With the outer ribs resting flush against the slit ribs. The final image shows the shutter safely in place.

The tubular, foam, pipe insulation is excellent for protecting the dome from the ladders. As well as offering plenty of friction to avoid the ladder sliding sideways. I use paving slabs on the ground. To stop the gently sloping ladders from sliding backwards. 

Sacks of dense material could also be use to restrain the bottoms of the ladders. Compost, sand or soil, for example. A steel bar, hammered well into the ground, is a further option. Ladders have poor friction with the ground when not inclined at their normal angle.

After lunch I will raise the second shutter. Rain is expected on Friday.

It was more difficult to lift the second shutter. As I had no anchor for the boat winch I clamped it to an inverted pallet. It took a couple of paving slabs to keep it from moving. The second shutter is now in place but needs the bracket angles adjusted. The outer rib is not upright. 

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