Tabernacle

[Mark Johnson]

The boat that I built previous to the last / current one, was a Seaclipper 28 trimaran. It had a massive tabernacle, made of a heavy aluminum casting. It was part of a mast kit, and I think that this tabernacle base was "one size fits all", so was ridiculous overkill for such a small trimaran. It had a 1" SS hinge pin, but with a loose enough fit, that the weight went on the mast bottom. The tabernacle hinge pin went through doughnut doublers on the mast that increased the mast wall thickness to about 5/8" at the pin. The base was bolted down to the deck, (with its doubler square underneath), by 6 @ 3/8" bolts. Under this doubler, was a 3' long 4X4 compression post, that delivered the stresses to the top of the CB trunk, which really spread out the load.

The fractional cutter rig was a dirt simple double triangle, with no spreaders, or removable feature to the lower staysail stay. John Marples has used this concept many times, and if the extrusion is large for its length, and the wires amply sized, as was mine, it is as strong as a tank! One just designs the rig to take the tabernacle's weak link into account.

I was a younger (= wilder) man then, and had the boat hovering at almost 20 knots on several occasions. (Full main & genoa in 30 knots) Spectators told me once, that they could just see the centerboard exit the bottom of the main hull! I pressed this boat hard, including the worst pounding I ever had at sea, and still consider the rig the strongest, proportionate to the boat, that I ever saw.

I only had occasion to once, but I could stand the mast with lines, tackles, a "push stick" and a helper. If it was needed often, I would've refined my system considerably.

To dismiss the tabernacle out of hand as weaker, is simply an improperly designed and built tabernacle rig... IMO.

Mark