Westerbork, Hervormde kerk

It was long unknown which organbuilder built the organ of Westerbork. In 1980 the condition of the organ had become very poor and the church council decided to restore the instrument.
Klaas Bolt, organist at the Grote kerk of Haarlem, was appointed adviser and Albert de Graaf as restorer.
First a historical investigation was started. The organ proved not to have been built for this church but for the Hervormde kerk of Beetgum. Petrus van Oekelen brought the organ in 1862 from Beetgum to Westerbork, when he built a new organ for Beetgum. Investigation of the archives at Beetgum pointed out that Christiaan Müller and Johann Michael Schwartsburg built it in 1726 for Beetgum.

In the 18th century Knock collected dispositions of organs the disposition of the organ of Beetgum is mentioned as follows:
Praestant 8 v.
Holpijp 8 v.
Octaaf 4 v.
Quint 3 v.
Super Octaaf 2 v.
Sexquialter discant
Mixtuur 3 St.
Tremulant
Afsluiting

History of the organ in Beetgum
The organ, Müller and Schwartsburg built, was not completely new. Part of the pipework is older. Probably parts of an older organ were used. Johann Michael Schwartsburg did the maintenance of the organ in the first years until his dead in 1748. From 1754 to 1759 Johannes Jans was tuning the organ. From 1760 to 1776 Pieter de Vries was maintaining the organ. From 1777 tot 1782 A. van Kampen out of Koudum. Next was Albertus S. Hempenius from 1784. Then Albertus van Gruisen, organbuilder in Leeuwarden. He started with substantial maintenance in 1792. In 1807 the windchannels were repaired. In 1819 Johann Adolf Hillebrand repaired the organ. He folied the pipes in the front and did a cleaning up. Albertus van Gruisen further on did the regular maintenance till his dead in 1843. Willem Hardorff takes over the company of Albertus van Gruisen and maintained the organ until Petrus Van Oeckelen built a new organ for the church and moved the old organ to Westerbork.

History in Westerbork
Van Oeckelen did not change much on the organ when he placed the organ in Westerbork. At a certain time a Viola di Gamba 8 vt was placed in stead of the Sexquialter. The organ further remained unaltered until 1953.
In 1953 Gebr. Van Vulpen out of Utrecht restored the organ. A new sexquialter was placed, the windchest was restored, the pipes were intonated at a low wind pressure of 60 mm, according to the ideas at that time. The openings at the pipefeet were enlarged and all the pipes where displaced half a tone.

Restoration by Albert H. de Graaf 1983-1987
On behalf of the restoration of the church, the organ was dismantled in 1983 an brought over to the workshop of de Graaf in Leusden. The restoration took place in the years 1986-1987. The adviser was Klaas Bolt. On the first of October 1987 the organ was inaugurated by a concert by Klaas Bolt

The restoration included:
*Repair of the case, painting the case in the same colours as Leeuwarden Grote kerk. Gold on the ornaments
*Repair of the bellows and windchannels.
*Repair of the mechanics.
*Repair of the, by the heating installation, very damaged windchest.
*Restoration of the pipework. Pipes of the mixtuur were displaced. The pipework was lengthened to a pitch of 440hz, because other solutions would cause damage of the front-pipes. Pipefeets were widened to cooperate with a windpressure of 72 mm.
*The Sexquialter of 1953 was replaces by a new one.

Description of the organ
The organcase has several characteristics of Christiaan Müller. But not all Müllers characteristics are very prominent on this organ. The typical Müller-characteristics as a seven-part front-structure and the division in 3 of the inner pipefields are not present.
The pipes in the front do have round mouths. The tinfoil dating from 1953 is retained. The profiles above the fronttowers and the forms of the carvework are very likely added in Leeuwarden and in Westerbork.
The case is made of oak. Perhaps parts of an older case were reused. The case has a depth of 87 cm and is painted in a deep red, like the organ in Leeuwarden.

Manuals
The manual does have very nice "bakstukken". They have different shape as the "bakstukken" of St. Bavo Haarlem and differ from the remaining "bakstukken" of the chamber-organs of Christiaan Müller. It is not quite sure that they are original, but it is difficult to decide the organbuilder who made them. The manual has lower keys of ivory and upperkeys of ebony. The pedal has 15 slats from C' to d'. The organ-seat is old and made of pine and is painted black. The stops are original, brown and not painted. The names of the stops are on wooden tablets.

Wind-supply
Behind the organ there are the original bellows in a case. At the north there are three "tredes" to manually provide the wind. Of course there is an electric motor also. Underneath the floor the main-windchannel is going to the windchest. On this main-windchannel there is an inlaying tremulant. The windchannel splits into two channels for the C- en the Cis-site. At the console of the organ there is a "Afsluiting" to close the windchannels. All windchannels are made of oak.
 
Windchest
The windchest is made of oak. The windchest is not divided, but has two windchannels. "Stokken" en "roosters" are made of oak too.
Cancels: b0 fs0 B Gs c0 e0 gs0/c1-c3/Fs E D C Cs Ds F/h2-es'/a f cs0A G H ds0 g0 h0.

Mechanics
Most of the mechanics for the manual and the registers are still original.

Disposition
Praestant 8' Treble double pipes
Roerfluit 8'
Octaaf 4'
Quint 2 2/3' bass/treble
Octaaf 2'
Mixtuur III
Sesquialter III
Trompet 8' bass/treble
Windlosser

Painting in grey by Maarten 't Hart, Balkbrug. Made in 1997.

Characteristics of the pipework
Most of the pipework is older than 1726. The front-pipes and the bigger inner-pipes are made in 1726. The pipework has a dark metallic colour and a high percentage of lead. The pipes are very thin.

Organists:
Joke Bartels Erica
Gerben Gritter Emmen
Geert Jan Pottjewijd Beilen