Ronstan Marine Systems DivisionRonstan Marine Systems Division
 
 

Series 75

CORE BLOCK™

Range Information | Applications | Materials | Related Items

Smart Features
  •  Class leading performance and sleek, contemporary styling
  •  Excellent dynamic and high static load performance
  •  Less than half the friction of the nearest competitor
  •  Durable aluminium alloy cheek plates
  •  Central hub hole can be used as a becket take-off or tie-up point

 

   
Product No.
Desc.
Sheave ØMax. Rope ØMax. Cable ØPin ØM.W.L.B. L.Weight

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Stock

Price

  in.in.inin. lb.lb.oz.        
 RF74100 RF74100 > Single

3

9/16

-

5/16

330

6600

12.5


 
 

  QTY
 

IN
STOCK

Price

$ 119.95

 RF74100AW RF74100AW > Single, aluminium rope/wire sheave

3

9/16

5/16

5/16

3300

6600

15.3


 
 

NOT
AVAILABLE
ONLINE

---

Price

$ 150.00

 RF74108 RF74108 > Halyard

3

9/16

-

5/16

330

6600

8.6


 
 

  QTY
 

IN
STOCK

Price

$ 109.95

 RF74108A RF74108A > Mast base block

3

9/16

-

5/16

3000*

6600*

8.1


 
 

  QTY
 

IN
STOCK

Price

$ 79.40

 RF74110 RF74110 > Single, becket

3

9/16

-

5/16

330

6600

15.1


 
 

  QTY
 

IN
STOCK

Price

$ 134.95

 RF74140 RF74140 > Stand-up, swivel

3

9/16

-

-

330

6600

16.5


 
 

NOT
AVAILABLE
ONLINE

---

Price

$ 199.95

 RF74151 RF74151 > Foot, single

3

9/16

-

-

330

6600

9.2


 
 

  QTY
 

IN
STOCK

Price

$ 129.95

 RF74202 RF74202 > Double, non-swivel head

3

9/16

-

-

330

6600

17.9


 
 

  QTY
 

IN
STOCK

Price

$ 199.95

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Range Information
 
Core Blocks™ are a true all round solution. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing.
 

Universal Bearing -

Dynamic and high static load performance

The Ronstan Universal Bearing incorporates our proven 2-stage bearing system

Stage 1 - Under moderate loads, Acetal ball bearings ensure minimum friction.

Stage 2 - Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless steel race takes over, maintaining low friction performance.

Additionally the ball bearings are configured to act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn’t perfect. Particularly important for cheek blocks.

 

Alloy cheek plates

Block cheeks are manufactured from the highest quality alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings.  Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear.

    
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Applications
  • Ideal for use on mainsheet, spinnaker sheet, vang, halyard and backstay applications on boats up to 14m (46ft).
  • General applications on larger yachts.
  • Alloy sheave models are available for use with wire.
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Materials
  • Sheave: U.V. stabilised acetal or anodised aluminium (AW models).
  • Cheek plates: Aluminium alloy
  • Ball Bearings: High compression strength carbon black acetal.
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