RG10-100 & RG10-130 Reduction gearbox (60′ – 95′)

Jefa RG10-100 reduction gearbox

The Jefa RG10-100 reduction gearbox transforms a rotational movement into a push-pull movement. The reduction gearbox is always positioned close to the rudder stock. Via a draglink with rose joints, the push-pull movement is transmitted to the tiller lever and rudder shaft. The RG10 gearbox is very versatile as it can be equipped with one (standard), or two input shafts. On top of that one can choose the output shaft at the opposite side of the input shafts (type 1) or at the same side (type 2). The gear ratio is 1:10 (3.5 revolutions of the input shaft for a corresponding 72 degrees of rudder travel). This can be increased with steps of 1.2:1 by using step ratio bevel boxes (4.3 turns with one step ratio and 5.2 turns with two step ratio bevel boxes). The output lever centres are 165 mm to a corresponding 250 mm centres of the tiller lever or 200 mm to a corresponding 307 mm of the tiller lever. This difference in length results in the so called “wide angle geometry”. Please click here for more in depth explanation. The RG10-100 gearbox has 4 positions to integrate an optional Jefa transmission autopilot drive unit. Integrating an autopilot drive in a steering system has never been so easy. The maximum input torque is 40.5 kgfm resulting in a maximum rudder torque at full rudder of 1183 kgfm. The maximum rudder torque according to the CE rating is 410 kgfm midships and 788 kgfm full rudder (the CE regulations use a safety factor of 150%). This makes the gearbox suitable for boats from 60′ to around 95′. Except for the input shafts and the gears, the complete gearbox is machined out of solid aluminium 6082 for maximum strength and minimum weight (26,5 Kgs). Positioning the reduction gearbox correctly to the rudderstock is very important for the wide angle geometry to function correctly. Please look at the mounting examples at the bottom of this page.
As the RG10-100 gearbox is a two stage gearbox, the rotation is reversed. Please notice this fact when setting up the rotations. This gearbox uses Ø22 mm pins and the heavy duty version of our draglinks. The pin on the gearbox is included, the pin for the tiller arm has to be ordered separately.


Jefa transmission bevel reduction gearboxes

Part No.Description
RG10-100Reduction gearbox 1:10 including output lever
RG10-130Reduction gearbox 1:13 including output lever
RG10-DBShaft and bracket for autopilot for RG10 gearbox

RG10-100 autopilot drive integration

The layout below shows a typical integration of a transmission autopilot drive unit on a type 1 RG10-100 reduction gearbox. The drive can be mounted on 4 positions: 2 at the input side and 2 at the output side.


RG10-100 operating centres in mm valid for 72° (2×36°) rudder travel.

Output centre distanceOffset distanceTiller centre distance
130 (short lever)N/AN/A
165 (standard long lever)127250
200 (extra long lever)162307

Art. 11590