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Self-aligning GRP lower roller bearings type 6GB000

 

Type 4S000 bearing

The table below shows all key dimensions of the 6GB000 series self-aligning GRP bottom roller bearings. The measurement D is the outside diameter for the sealing gaiter.  Click on the pictures for a detailed view.

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PART NO.

RUDDER SHAFT dia.

BODY dia. "D"

HEIGHT "H1"

WEIGHT

WORKING
LOAD (max)

6GB060 - 6GB079

60 to 79 mm

150 mm

300 mm

1,3 kg

4200 kg

6GB080 - 6GB104

80 to 104 mm

170 mm

300 mm

1,7 kg

5600 kg

6GB104 - 6GB140

104 to 140 mm

210 mm

300 mm

2,5 kg

7300 kg

The applications for the 6GB000 series bearing:
The 6GB000 series bearings are specially designed for production yachts. This bearing type combines 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 housing is made of GRP (resin type PROSET 125) , allowing it to be laminated directly into the hull. A rudder tube is not required as the bearing housing is designed to extend above the boats waterline. It must be sealed to the rudder shaft with a gaiter. In the case of female moulded production boats the bearings housing can be mounted into the hull mould before lamination and gel coating begins. After gel coating the hull the peel-ply is removed from the bearing's outer face and the hull is laminated as usual with the exception that the hull laminate runs up the side of the bearing housing. This means that the bearing is already installed in the hull upon de-moulding, thus providing an integrated rudder support, and saving production time.

Installation of JEFA Marine composite bearings in female moulded hulls:

  1. 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.
  2. With the peel ply intact, tape a bag over the top of the bearing so as to cover the entire bearing neatly.
  3. Gel-coat the hull.
  4. Just prior to lamination, carefully remove the bag and the peel ply from the bearing.
  5. 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 sleeve.
  6. 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.
  7. 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.
  8. When the hull is de-moulded and the deck bearing is ready for installation the bearing cassette 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.