Tabernacles
Page published 30 March 2008
If your cruising ground is likely to include many bridges then a tabernacle is exceedingly useful, to aid the lowering of the mast, especially if the bridges to be cleared are particularly low. This is a recent example supplied by Marine Weld, of North Walsham:
The measurements for this example follow:
| Steel Thickness: | 5mm |
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Baseplate: |
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| Length: | 150mm |
| Width: | 120mm |
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Uprights: |
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| Height: | 298mm |
| Spindle Centre: | 254mm |
| Width: | 88mm |
| Space Between: (Note #1) | 57mm |
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Backplate: |
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| Height: | 117mm |
| From Base: (Note #2) | 85mm |
NOTES:
1. The width between the two vertical plates of the tabernacle is just sufficient to take the mast, which has a tube welded into it to take the pivot bolt. Adjust this measurement to suit your mast!
2. The distance from the base to the bottom of the back plate must be determined by the halyard pulleys. On this example the pulleys for side by side, not one above the other.
3. The back plate not only provides stiffness to the structure, but also a loop for securing the kicking strap.
4. The hinge bolt has no thread between the plates and a domed nut is used so that it self-tightens, rather than depend on squeezing the tabernacle uprights.
5. When upright the base of the mast sits snugly on the tabernacle base plate, so that the weight of the mast is taken on the base not the pivot. Accordingly, there can be no "extensions" to the rear of the mast base (e.g. pivot bracket) to allow the mast to swing clear of the tabernacle.
(The casting on the base of the mast seen below looks a little untidy. There was wear where the original Pop Rivets secured the casting to the mast and the rivets have been been replaced with somewhat crude, but secure, welding.)
Note how the base of the mast needed the original trailing pivot to be sawn away. As the mast is pivoted centrally any extension behind the mast would have fouled the base plate of the tabernacle as it swings forward.
The base plate of the tabernacle is secured to the cabin top by four bolts. These pass all the way through the cabin roof and the reinforcing plate on the ceiling of the cabin
When raising the mast you need to ensure that the halyards are pulled through the tabernacle otherwise they tend to snag the mast as it reaches the vertical. What "tricks" do tabernacle users use to ensure they always do this?
