TWIN-PETP roller bearings type 6S

The table below shows all key dimensions of the 6S series TWIN-PETP roller bearings in GRP tube. The measurement D is the outside diameter of the GRP tube. 
Click on the pictures for a detailed view.


Bottom Bearing dia. "db"

Top Bearing dia. "dt"

TUBE dia. "D"



LOAD (max)

6S030 - 6S049

30 to 49 mm

30 to 49 mm

90 mm

max. 1000 mm

1.9 kg

1300-1800 kg

6S050 - 6S069

50 to 69 mm

30 to 69 mm

110 mm

max. 1000 mm

3.1 kg

2500-3200 kg

6S070 - 6S089

70 to 89 mm

50 to 89 mm

130 mm

max. 1000 mm

3.6 kg

4200-4800 kg

6S090 - 6S109

90 to 109 mm

50 to 109 mm

150 mm

max. 1000 mm

4.5 kg

4900-6200 kg

6S110 - 6S139

110 to 139 mm

70 to 139 mm

180 mm

max. 1000 mm

5.7 kg

6300-8400 kg

6S140 - 6S169

140 to 169 mm

90 to 169 mm

210 mm

max. 1000 mm

6.3 kg

8400-9500 kg

*1: Weight taken with a 800 mm tube.
*2: Longer tubes are available at a surcharge.

6S specification form:
Please click the left icon to open the 6S specification form in Adobe PDF. You can fill in the gray field with the correct info and tick the appropriate boxes. This form is required to guarantee a correct production of your bearing.

The applications for the 6S series bearing:
The 6S series bearings are developed as a more affordable alternative on the 6D bearings. The bearing is made of PETP (also known as Arnite, Ertalyte, Sustodur & Ultradur) in a GRP tube, allowing it to be laminated directly into the hull. It's primarily meant to be used on tiller steered boats, but could be used on wheel steered boats if the tiller arm / quadrant is above the top bearing.

Installing the 6S bearing:

Installation of JEFA Marine composite bearings:

  1. The GRP tube of the 6T bearing is delivered with a shiny resin surface. To achieve a good bonding to the hull it's important to roughen the outside surface with a grinder or sanding machine so no shiny surface is left. This should be done just prior to laminating the bearing to the hull.
  2. Secure the bearing-housing in it's place in the hull. The bearing should be jigged in place firmly so that it won't alter position when worked during lamination and remove the bearing ball to make sure no resin will enter the rollers.
  3. Make sure the hole in the hull is a few millimeters bigger than the bearing outside diameter and tape close the gap at the bottom.
  4. Cast some resin in the gap to close off the hull laminate .
  5. Laminate the hull and bearing creating an outer skin. It can be tapered down beginning just above the self aligning bearing in the bearing tube.
  6. On top of this outer skin there should be a foam ramp or fillet (minimum 200 kilo/m3 density), which encircles the bearing housing. Make a wooden circular tool to create a nice fillet.
  7. Laminate the hull and bearing making sure that the laminate runs up the side of the bearing in full thickness. It can be tapered down over a 100 mm span beginning just above the self aligning bearing in the bearing tube.
  8. There should always be a skin joint around the bearing that is at least three times the bearing housings measurement in diameter, and the laminate should have a minimum thickness of 1.5x(1.8+(LWL/1.8), this thickness is not including the foam ram mentioned bellow. (LWL in Meters).
  9. In stead of using a filled around the first outer skin, one can also make a web of triangles which will be included in the final lamination (see model below).

Please remember that these guidelines represent good practice, however all structural components of a sailing vessel should be engineered by a qualified engineer for the actual case. JEFA MARINE takes no responsibility for any structural failures which might result from the use of these guidelines.

Installation example of the 6S bearing not using a fillet for stiffness but a web structure

6S examples:

Fitting tiller stops to the 6S bearings:
The 6S series bearings standard have no tiller stop arrangement . By adding a flange with stops which can be bolted to the deck, additional tiller stops can be added. There is one flange to work with our tiller heads 25 mm to 40 (6SP035STP) and one to work with our 50 mm tiller head (6SP050STP).

6SP035STP dimensions:
6SP050STP dimensions:




corresponding tiller heads


Tiller stop up to 40 mm shaft

25 - 40 mm


Tiller stop up to 50 mm shaft

50 mm