GRP-PETP bottom roller bearings type 61000

The table below shows all key dimensions of the 61000 & 61000S (S = seals) series PETP roller bearings in GRP tube. The measurement D is the outside diameter of the GRP tube.

PART NO. Bearing dia. "d" TUBE dia. "D" WEIGHT *1
61000 series		 WEIGHT *1
61000S series		 WORKING LOAD (max)
61030 - 61049 30 to 49 mm 90 mm 3.6 kg 4.1 kg 1300-1800 kg
61050 - 61069 50 to 69 mm 110 mm 3.8 kg 4.0 kg 2500-3200 kg
61070 - 61089 70 to 89 mm 130 mm 4.1 kg 4.5 kg 4200-4800 kg
61090 - 61109 90 to 109 mm 150 mm 4.2 kg 4.9 kg 4900-6200 kg
61110 - 61139 110 to 139 mm 180 mm 4.4 kg 4.9 kg 6300-8400 kg
61140 - 61169 140 to 169 mm 210 mm 5.0 kg 5.5 kg 8400-9500 kg
*1: Weight taken with a 1000 mm tube.

PART NO. Bearing dia. "d" TUBE dia. "D" WEIGHT *1
61000 series		 WEIGHT *1
61000S series		 WORKING LOAD (max)
61030 - 61049 30 to 49 mm 90 mm 3.6 kg 4.1 kg 1300-1800 kg
61050 - 61069 50 to 69 mm 110 mm 3.8 kg 4.0 kg 2500-3200 kg
61070 - 61089 70 to 89 mm 130 mm 4.1 kg 4.5 kg 4200-4800 kg
61090 - 61109 90 to 109 mm 150 mm 4.2 kg 4.9 kg 4900-6200 kg
61110 - 61139 110 to 139 mm 180 mm 4.4 kg 4.9 kg 6300-8400 kg
61140 - 61169 140 to 169 mm 210 mm 5.0 kg 5.5 kg 8400-9500 kg
*1: Weight taken with a 1000 mm tube.

61000 specification form:

Please click the left icon to open the 61000 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.

61000S specification form:

Please click the left icon to open the 61000S 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 61000 series bearing:
The 61000 series bearings are developed as a more affordable alternative to the 6T self-aligning bearings. It’s also an alternative to the 41000 series bearing when a metal bearing housing is not appreciated. 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. As the bearing is non self-aligning, it should be laminated in the hull with the rudder shaft mounted or for production boats with a dummy shaft.

Choosing between the 61000 series and 61000S series bearing:

The choice between the 61000 series bearing and the 61000S series bearing (including 2 PUR lip seals) is fully depending on the available space above the bearing. The left solution, tube and gaiter, is the preferred solution as there are specific advantages:

  • The longer the tube, the higher the water ingress point will be in the hull, the less chance for water entering the hull.
  • The gaiter is a 100% watertight solution without any friction and wear to the shaft.
  • The gaiter is easy replaceable in time, without the need to lift the boat and drop the rudder shaft (necessary to replace lip seals). Gaiters can be bought non-glued, as spare or as replacement. More info in this page.

Installing the 6S bearing:

Installation of JEFA Marine composite bearings:

  1. The 61000 series bearing is not self-aligning. To achieve a correct alignment to the rudder shaft, it’s vital the shaft is present in the bearing while laminating. As the tolerance between the bearing and the shaft is only a few hundreds of a mm, any misalignment will result in a bad bearing run and potential problems in the future.
  2. The GRP tube of the 61000 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.
  3. 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.
  4. 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.
  5. Cast some resin in the gap to close off the hull laminate .
  6. 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.
  7. 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.
  8. 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.
  9. 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).
  10. 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.

Service information:

Please visit our FTP server for service information, parts lists and exploded views.