Front View: Closed	Rear View: Closed
Front View: Open for Rigging	Rear View: Open for Rigging

Technical Details

I acquired this Holthausen descender from Álvaro Gomes da Fonseca in 2014.

The Holthausen descender is 209 mm. tall, 120 mm. wide, 48 mm. thick, and weighs 1325 g.

The central portion is a cast steel shank with helical and longitudinal rope grooves.

The grooves are 15 mm. wide 11.8 mm. deep, so using 11 mm. rope is indicated. Each end has an 8.5 mm. eyebolt attachment point. These are fixed so they cannot unscrew, but it is not clear how. Two more eyebolts attach from the side. One quarter of their eye is cut away, leaving a hook that can be used for tying off. The cover is made from 1.8 mm sheet steel rolled into half of a circular cylinder. The side eyebolts hold the cover in place. Inside the cover are two bronze inserts, one at each end. These are riveted to the cover. Their inner surface is cut into a sloping U-groove. They guide the rope and protect the edge of the cover from abrasion.

One end has "BREVETÉ," "N^o 345," "France & Étranger," and "H" and "K" with a torch in between. The other end has "DESCENDEUR A SPIRALE." All these markings are raised from the casting except the stamped serial number "345."

Comments

My descender came with a short piece of 4-strand laid 11 mm. rope attached, and I presume that is what it was intended to be used with. Oh! for the good old days of natural fiber rope! Back in those days, the weight of the descender did not matter as much as it does today, and this beast is heavy. What do you expect from steel? Oh, yes, rust.

The design allows for using two, three, or four wraps. Increasing the number of wraps increases friction dramatically (remember the snubbing formula!) but changing the number of wraps on rappel is not feasible.

The Miller Descent Device is a more modern version of concepts used in the this descender.

History

At first, I don't know who made this descender, so I used "H. K." as if it were the name of the device.

In 2021, Jean-Luc Lamouroux for sent me the catalog page. He wrote, "In the 19th century in France (perhaps in Europe), firefighters used Spiral descenders to save people in burning buildings." He also sent me a picture of one with serial number 2316 that appears to be identical to mine.

Tarquin Wilton-Jones wrote to me in 2023, telling me that the catalog page was from 1899 and that the Musée des Sapeurs-pompiers de Loire Atlantique has a copy. Tarquin later found the 4-volume set “La Marine à l'Exposition universelle de 1878” containing a discussion and an illustration of this descender. Tarquin also found that Frederic Holthausen applied for and received U.S. Patent #181,577 for his descender in 1876.

La vie Parisienne, January, 1876	Le Figaro, July, 1876