|Front View||Rear View||Side View|
|Front View: Open for Rigging||Rear View: Open for Rigging|
I acquired my Repetto Bis-Bang from Expé-Spelemat in 2008. The Bis-Bang is 177 mm. tall, 56 mm. wide, and 41 mm. thick. Mine weighs 247 g.
The two side plates are made of 3.1 mm. aluminum. The lower ends of the side plates are bent to converge at the attachment point. The attachment point on the fixed side plate is enlarged to a 22 mm. high by 13 mm. wide hole located 3 mm. off center. A similar hole on the pivoting side plate has been cut open on the narrow side, so the side plate resembles a hook. The opening of the hook is covered by a spring loaded, stamped steel, sheet metal guard which is attached to the side plate with a semi-tubular rivet.
The lower bollard is turned aluminum with four rectangular projections keep it from rotating on the fixed side plate. It is drilled and tapped then bolted to the fixed side plate with 8 mm. bolts. Shoulder nuts lock the bollard in place and also retain the pivoting side plate. The bollard is 27.3 mm. long, making the Bis-bang suitable for doubled ropes. The bollard has a turned U-groove. The diameters of the ends of the bollard are 41.2 mm., and the center diameter is 33 mm.
The upper bollard is turned stainless steel. It is riveted to the fixed side plate. This bollard has two U-shaped grooves. The end at the side plate is 14.9 mm. in diameter, the two grooves are 8 mm., the wide point between the grooves 12.0 mm., and the outer end at the swinging side plate 14.8 mm. Outside this, there is a groove to retain the closed side plate.
The auxiliary bollard is also turned stainless steel, and riveted to the fixed plate. It is 14.9 mm. at the side plate, tapers in 3 mm. to 8 mm., maintains this diameter for 20.5 mm., and then expands to 15 mm. at the swinging plate. Outside this, there is a groove to retain the closed side plate.
The pivoting side plate pivots on the shoulder nut holding the lower bollard and has a slot to allow clearing grooves in the upper bollard and auxiliary bollard.
The pivoting side plate is printed with an open book-with-an-"i" icon, an illustration showing how the
descender is threaded, "REPETTO," "Bis Bang"
in an ellipse, and an utterly indecipherable icon that might be
mistaken for a map (or a Mayan head glyph?). Actually, the icon is a profile
of a man’s face.
Double-rope bobbins are rare, and I haven't seen one commercially available since I acquired my Petzl Double-rope Bobbins in 1981. The Bis Bang lower bollard has a single rope groove similar to the one on the Petzl Version A. I prefer to have two rope grooves (as in the Petzl Version B). When a double rope bobbin is rigged for extra friction during a single rope rappel, the two groove design has the advantage of keeping the rope paths separated on the lower bollard, where the directions of rope motion may be opposite.
The Bis Bang’s upper bollard is considerable smaller than normal, which subjects the rope to a much sharper bend. While this might not matter much for thin climbing lines, it is hard on stiff, tightly-woven caving ropes like those preferred by many cavers here in the U. S. A.