Self-aligning TWIN-PETP roller bearings type 6D

The table below shows all key dimensions of the 6D series self-aligning TWIN-PETP roller bearings in GRP tube. The measurement D is the outside diameter of the GRP tube.

PART NO. Bottom Bearing dia. "db" Top Bearing dia. "dt" TUBE dia. "D" HEIGHT "H" *2 WEIGHT *1 WORKING LOAD (max)
6D030 - 6D045 30 to 45 mm 30 to 45 mm 90 mm max. 1500 mm 1.9 kg 1300-1800 kg
6D046 - 6D060 46 to 60 mm 30 to 60 mm 110 mm max. 1500 mm 3.1 kg 2500-3200 kg
6D061 - 6D072 61 to 72 mm 30 to 72 mm 130 mm max. 1500 mm 3.6 kg 4200-4800 kg
6D073 - 6D095 73 to 95 mm 30 to 95 mm 150 mm max. 1500 mm 4.5 kg 4900-6200 kg
6D096 - 6D125 96 to 125 mm 41 to 125 mm 180 mm max. 1500 mm 5.4 kg 6300-8000 kg
6D126 - 6D160 126 to 160 mm 58 to 160 mm 210 mm max. 1500 mm 6.1 kg 8100-10100 kg
*1: Weight taken with a 800 mm tube.
*2: Longer tubes are available at a surcharge.

PART NO. Bottom Bearing dia. "db" Top Bearing dia. "dt" TUBE dia. "D" HEIGHT "H" *2 WEIGHT *1 WORKING LOAD (max)
6D030 - 6D045 30 to 45 mm 30 to 45 mm 90 mm max. 1500 mm 1.9 kg 1300-1800 kg
6D046 - 6D060 46 to 60 mm 30 to 60 mm 110 mm max. 1500 mm 3.1 kg 2500-3200 kg
6D061 - 6D072 61 to 72 mm 30 to 72 mm 130 mm max. 1500 mm 3.6 kg 4200-4800 kg
6D073 - 6D095 73 to 95 mm 30 to 95 mm 150 mm max. 1500 mm 4.5 kg 4900-6200 kg
6D096 - 6D125 96 to 125 mm 41 to 125 mm 180 mm max. 1500 mm 5.4 kg 6300-8000 kg
6D126 - 6D160 126 to 160 mm 58 to 160 mm 210 mm max. 1500 mm 6.1 kg 8100-10100 kg
*1: Weight taken with a 800 mm tube.
*2: Longer tubes are available at a surcharge.


6D specification form:

Please click the left icon to open the 6D 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 6D series bearing:
The 6D series bearings combine a very simple installation with a very smooth operation under all circumstances as the bearing will always be aligned to the rudder shaft. 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.
As the bearing is self-aligning, there will be no torque transmitted to the hull, just rudder forces and the bearing will never try to twist out of the hull. The bearing ball can be easily dismounted out of the housing for installation safety or replacement when any damage in the future may happen.

Installation of JEFA Marine composite bearings in female moulded hulls:

  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. Tape a bag over the top of the bearing to cover the entire bearing neatly.
  4. Gel-coat the hull.
  5. Just prior to lamination, carefully remove the bag.
  6. Laminate the hull 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.
  7. 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.
  8. When laminating the hull the first 10% of the prescribed laminate should be laid directly into the hull to bearing housing joint. On top of this “outer skin” there should be a foam ramp or fillet (minimum 200 kilo/m3 density), which encircles the bearing housing. The remainder of the laminate runs up over the foam ramp.
  9. When the hull is de-moulded and the deck bearing is ready for installation the bearing ball can be inserted into the two slots in the bearing housing and rotated into place.
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.
 

6D examples:


Fitting tiller stops to the 6D bearings:

The 6D 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 Ø25 mm to Ø40 (6SP035STP) and one to work with our 50 mm tiller head (6SP050STP).


6SP035STP dimensions:

6SP050STP dimensions:

TILLER STOPS

PART NO. DISCRIPTION corresponding tiller heads
6SP035STP Tiller stop up to 40 mm shaft 25 - 40 mm
6SP050STP Tiller stop up to 50 mm shaft 50 mm