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Spars, Rigging, and Hardware for Sailboats

Rig-Rite, Inc.
Phone: (001) 401-739-1140 -- FAX: (001) 401-739-1149
www.RigRite.com          Ordering/Questions

Isomat/Sparcraft Mast Base Turning Blocks


Many Isomat/Sparcraft Mast Steps and Deck Collars feature provisions for attachment of Blocks and Shackles using a variety of Bails, Pins and threaded Studs with nuts. Blocks are available with integral threaded Studs and nuts. Threaded Studs, Pins, and Bails, and Blocks for use with them are available separately. See also: Z-Spar Mast Base Turning Blocks, Halyard Lead Blocks, and other Blocks. 

Some Isomat Masts have integral Welded Exit Boxes at the base of the mast for leading internal halyards out of the Mast at Deck level, eliminating the need for Mast Base Turning Blocks. For Parts for them, See Welded Mast Base Exit Boxes.
 

Blocks w/ Threaded Studs for New-Style Steps & Collars
Threaded Block Studs w/ Nut
Block Stud Pins
Blocks for Steps & Collars using Block Studs & Block Pins
Mast Step & Deck Collar Bails
Blocks w/ Shackle, for Steps & Collars using Bails
Mast Base Block Springs


Blocks w/ Threaded Studs for New-Style Steps & Collars
SS Blocks with delrin or aluminum sheaves are specially designed to attach to all New-Style Isomat Mast Steps and Deck Collars. Blocks incorporate a 12mm SS stud, threaded (3/8-16) on the end, and include special Nut. SS Nut slides into recess in side of deck casting and block screws in through hole in top. New design allows Block to remain upright without spring, yet still allows full articulation. Threaded Block Studs are available separately (below) for use with other blocks or attachments.
Mast Base Turning Block w/ 2" Sheave: NGA-40:
Block with 2" (50mm) diameter delrin sheave will accommodate line up to 7/16" (12mm) diameter. Designed to attach to all New-Style Isomat Mast Steps and Deck Collars with 12mm (1/2") holes, special nut is included. Safe working load is 1750 lbs. (795Kg).

 

NGA-40

Mast Base Swivel Block w/ 2" Sheave: NGA-40SW:
Swivel Block with 2" (50mm) diameter delrin sheave will accommodate line up to 7/16" (12mm) diameter. Designed to attach to all New-Style Isomat Mast Steps and Deck Collars with 12mm (1/2") holes, special nut is included. Safe working load is 1750 lbs. (795Kg). Swivel Block provides superior articulation to standard unit. Special as original on Beneteau Oceanis 321 and others.

 

Mast Base Turning Block w/ 2" Aluminum Sheave: NGA-40A:
Block with 2" (50mm) diameter Aluminum sheave will accommodate wire up to 3/16" diameter and line up to 7/16" (12mm) diameter. Designed to attach to all New-Style Isomat Mast Steps and Deck Collars with 12mm (1/2") holes, special nut is included. Safe working load is 1750 lbs. (795Kg).

 


Mast Base Turning Block w/ 2 3/8" Sheave: NGA-41:
Block with 2 3/8" (60mm) diameter delrin sheave will accommodate line up to 1/2" (14mm) diameter. Designed to attach to all New-Style Isomat Mast Steps and Deck Collars with 12mm (1/2") holes, special nut is included. Safe working load is 2250 lbs. (1020Kg).

 

 

NGA-41

Mast Base Turning Block w/ 2 3/8" Aluminum Sheave: NGA-41A:
Block with 2 3/8" (60mm) diameter Aluminum sheave will accommodate wire up to 1/4" diameter and line up to 1/2" (14mm) diameter. Designed to attach to all New-Style Isomat Mast Steps and Deck Collars with 12mm (1/2") holes, special nut is included. Safe working load is 2250 lbs. (1020Kg).

 



Threaded Block Studs w/ Nut
Threaded Block Studs with Nut, to fit New-Style Isomat Mast Steps and Deck Collars, are available separately for use attaching items including shackles and other blocks. New-Style Steps and Collars allow for the addition of Block Studs at any time without being removed from the deck. Stainless Steel Block Studs have an upper attachment hole and a threaded lower end to fit special Nut. SS nut slides into recess in side of deck casting, Block Stud screws into nut through hole in top of deck casting.
 
Threaded Block Stud - Lightweight: NG1-22:
NG-1 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud screws in through hole in top. Stud is 42mm (1 5/8") long x 12mm (15/32") diameter with a 1/4" (6mm) hole for attachment of shackle or block. Lower end has an 8mm thread x 3/8" (10mm) long. Includes special large nut.

 

NG1-22
Threaded Block Stud - Lightweight w/ 12mm hole: NG1-22LB:
NG-1 SS Block Stud with nut and bushing to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud (w/ bushing) screws in through hole in top. Forged Stud is 47mm (1 7/8") long x 8mm (5/16") diameter (12mm (15/32") OD w/ bushing) with a 12mm (15/32") hole for attachment of shackle or block. Lower end has an 8mm thread x 3/8" (10mm) long. Includes special large nut.

 

Threaded Block Stud - Lightweight w/ Link Plates & 1/4" Pin: NG1-22LB-LP:
NG-1 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. Unit is as NG1-22LB, but with SS spacer and permanently attached Link Plates for attachment of Blocks without shackles. Link Plates are 1/2" wide (between straps) and include 1/4" Pin.
 

 

 

 

Threaded Block Stud w/ Bracket & 5mm Screw Pin: NG1-22T:
NG-1 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud screws in through hole in top. Unit is 55mm (2 1/8") long, formed triangle has a 16mm (5/8") ID, and includes a 5mm screw for attachment of shackle or block. Lower end has an 8mm thread x 3/8" (10mm) long. Includes special large nut.

 


Threaded Block Stud - Heavy-Duty: NG2-22:
NG-2 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud screws in through hole in top. Stud is 52mm (2 1/16") long x 14mm (9/16") maximum diameter with a 12mm shaft and a 5/16" (8mm) hole for attachment of shackle or block. Lower end has an 8mm thread x 3/8" (10mm) long. Includes special large nut.

 

NG2-22
Threaded Block Stud - Heavy-Duty w/ 12mm hole: NG2-22L:
NG-2 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud screws in through hole in top. Forged Stud is 49mm (1 15/16") long with a 12mm shaft and a 12mm (15/32") hole for attachment of shackle or block. Lower end has an 8mm thread x 3/8" (10mm) long. Includes special large nut.

 

Threaded Block Stud - Heavy-Duty w/ Link Plates & 1/4" Pin: NG2-22L-LP6:
Threaded Block Stud - Heavy-Duty w/ Link Plates & 10mm Pin: NG2-22L-LP10:
NG-2 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. Unit is as NG2-22L, but with permanently attached Link Plates for attachment of Blocks without shackles. Unit with 1/4" Pin has 7/16" (12mm) between the Link Plates, unit with 10mm Pin has 1/2" (13mm) between the Link Plates.

 

 

 

Threaded Block Stud - Wide: NG2-22W:
Heavy-Duty Wide NG-2 SS Block Stud with nut to fit all New-Style Isomat Steps and Collars. SS nut slides into recess in side of deck casting and Block Stud screws in through hole in top. Special Wide Stud is suitable for direct attachment to a variety of Blocks with Bolt for Block Studs, below. Wide Stud is 50mm (2") long x 16mm (5/8") wide (at hole), with a 12mm shaft and a 1/4" (6mm) hole for attachment of shackle or block, hole can be drilled to 5/16" (8mm) for select applications. Lower end has a 3/8-16 thread, nut is included.

 

 

NG3 Threaded Block Stud w/ Triangular U-bracket: NG3-22T:
NG-3 SS Block Stud with triangular U-bracket and nut to fit Isomat Steps and Collars with 14mm mounting holes. Stud is 14mm (9/16") maximum diameter with a 12mm thread. Bracket inside has 3/4" (19mm) clearance and includes a 5/16" (8mm) Pin for attachment of shackle or block. As used on NG105-4 Mast Step on Catalina 470, and others.

 

NG3 Threaded Block Stud w/ U-bracket: NG3-22U:
NG-3 SS Block Stud with U-bracket and nut to fit Isomat Steps and Collars with 14mm mounting holes. Stud is 14mm (9/16") maximum diameter with a 12mm thread. Bracket inside has 3/4" (19mm) clearance and includes a 5/16" (8mm) Pin for attachment of shackle or block. As used on NG105-4 Mast Step on Catalina 470, and others.

 

 

Block Stud Pins
Clevis Pin-like Block Stud Pins fit Isomat Steps and Collars without Nut Slots, and must be installed before attaching the Step or Collar to the Deck.
 
NG2 Mast Step Block Stud Pin - 12mm: NG2-21:
12mm SS Clevis Pin-shaped Block Stud is used for attachment of shackle or block to lead halyards aft. Fits in integral recessed 12mm hole in a variety of Mast Steps and Deck Collars. Block Stud is installed from underside of Casting, Casting must be removed to install Block Studs. Small head Block Stud is 12mm diameter x 45mm (1 3/4") long (maximum), with a 30mm (1 3/16") grip length and a 6mm (1/4") hole for shackle pin or Block bolt. 

 

NG2 Mast Step Block Pin - 12mm Special: NG2-21PX:
Special 12mm SS Block Pin is used for attachment of shackle or block to lead halyards aft. Fits in integral recessed hole in NG60-4X, and other Mast Steps. Block Pin is installed from underside of Mast Step Casting, Mast Step must be removed to install Block Pins. Large head Block Pin is 12mm (<1/2") diameter x 45mm (1 3/4") long (maximum), with a 30mm (1 3/16") grip length and a 6mm (1/4") hole for shackle pin or Block bolt.

 

NG2-20P


NG3 Mast Step Block Pin - 14mm: NG3-21:
14mm SS Block Pin is used for attachment of shackle or block to lead halyards aft. Fits in integral recessed hole in Isomat Steps and Collars with 14mm mounting holes. Block Pin is installed from underside of Mast Step Casting, Mast Step must be removed to install Block Pins. Special Block Pin is 14mm (9/16") diameter x 54mm (2 1/8") long (maximum), with a 35mm (1 3/8") grip length and an 8mm (5/16") hole for shackle pin or Block bolt.

 

NG3 Mast Step Block Pin Ass'y w/ Toggle - 14mm: NG3-21PTA:
Special 14mm SS Block Pin Assembly includes standard 14mm Pin, NG3-21, and cast SS Toggle with a 8mm (5/16") Pin for attachment of shackle or block. Removable Toggle is attached with a separate 8mm Pin (included), and has 5/8" (17mm) inside jaw clearance. Unit fits in integral recessed hole in Isomat and Sparcraft Steps and Collars with 14mm mounting holes. Block Pin is installed from underside of Mast Step Casting, Mast Step must be removed to install Block Pins.

 

 

NG3 Block Pin Toggle for 14mm Pin: NG3-21TA:
Heavy-duty Block Pin Toggle only, as used in NG3-21PTA, above. Investment cast SS Toggle is 26mm (1") wide with a 5/8" (17mm) inside jaw clearance and includes (2) 8mm Pins for attachment to 14mm Block Pin and Block. Assembly fits on NG3-21 Block Pin. Unit is marked 48093000014.

 

 


Blocks for Block Studs & Pins
Blocks incorporate a Pin or Bolt for attachment to Block Studs and Block Pins listed above. Blocks with Bolts include Nylon Washers to allow for centering Block on Block Stud, Bolt is tightened to allow Block to remain upright regardless of halyard tension.

 

Swivel Block w/ 70mm Sheave, 8mm Pin: NGA-44-70S:
Sparcraft Swivel Block with 70mm (2 3/4") diameter delrin sheave will accommodate line up to 5/8" (16mm). Black plastic Swivel Block includes 8mm Pin for use with all Block Studs and Pins with an 8mm hole.

 


Bolt-on Turning Block w/ 2" Sheave: NGA-40UA:
Black Aluminum Block with 2" (50mm) diameter delrin sheave will accommodate line up to 7/16" (12mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.   2W

 

Bolt-on Turning Block w/ 2" Aluminum Sheave: NGA-40UAA:
Black Aluminum Block with 2" (50mm) diameter Aluminum sheave will accommodate wire up to 3/16" diameter and line up to 7/16" (12mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.

 

Bolt-on Stainless Turning Block w/ 2" Aluminum Sheave: NGA-40USA:
Stainless Steel Block with 2" (50mm) diameter Aluminum sheave will accommodate wire up to 3/16" diameter and line up to 7/16" (12mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.

 


Bolt-on Turning Block w/ 2 3/8" Sheave: NGA-41UA:
Black Aluminum Block with 2 3/8" (60mm) diameter delrin sheave will accommodate lines up to 1/2" (14mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.   5W

 

Bolt-on Turning Block w/ 2 3/8" Aluminum Sheave: NGA-41UAA:
Black Aluminum Block with 2 3/8" (60mm) diameter Aluminum sheave will accommodate wire up to 1/4" diameter and lines up to 1/2" (14mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.

 

Bolt-on Stainless Turning Block w/ 2 3/8" Aluminum Sheave: NGA-41USA:
Stainless Steel Block with 2 3/8" (60mm) diameter Aluminum sheave will accommodate wire up to 1/4" diameter and lines up to 1/2" (14mm) diameter. Includes 1/4" SS Bolt, Locknut and Nylon Washers for use with all NG1 and NG2 Block Studs and Mast Step Block Studs.

 



Mast Step & Deck Collar Bails
Special Mast Step and Deck Collar Bails are used with most Isomat Mast Steps and Deck Collars.
 
NG1 Mast Step & Deck Collar Bail: NG1-20:
SS Formed Bail is used for attachment of blocks and lines. Fits in integral slots of NG37 and smaller Mast Steps, and in sides of NG70 and smaller Deck Collars. Bails are installed from underside of Mast Step or Deck Collar Casting, Casting must be removed to install Bails. Bail is made from 8mm (5/16") rod, and is 2 1/16" (53mm) long x (maximum) 1" (25mm) high.

 

NG1-20
NG2 Mast Step & Deck Collar Bail: NG2-20:
SS Formed Bail is used for attachment of blocks and lines. Fits in integral slots of NG46 and larger Mast Steps, in sides of NG86 and larger Deck Collars, and in aft side of all Deck Collars. Bails are installed from underside of Mast Step or Deck Collar Casting, Casting must be removed to install Bails. Bail is made from 10mm (3/8") rod, and is 2 3/4" (70mm) long x (maximum) 1 15/16" (50mm) high.

 

NG2-20
NG3 Mast Step Bail Assembly: NG3-20A:
SS Formed U-bolt type Bail is used for attachment of Boom Vang or/and standard blocks for leading halyards aft. Fits in integral holes in NG105 Heavy-Duty Mast Step. Bail Nuts are installed from underside of Mast Step Casting, Mast Step must be removed to install Bail(s). Bail is made from 12mm (1/2") rod, and is 3" (78mm) long x 1 9/16" (40mm) between centers. Assembly includes Bail and (2) 12mm jam Nuts.

 

NG3-20A


Blocks w/ Shackle for Steps & Collars using Bails
Swivel Blocks incorporate a SS Shackle for attachment to Bails on all Old-Style Mast Steps and Collars, and on New-Style NG 105 Mast Steps. These blocks are also used for Spinnaker Halyards, and in a variety of other applications.
 
Stainless Swivel Block w/ 2" Sheave: Sch 505-05:
SS Swivel Block with 2" (50mm) diameter delrin sheave will accommodate line up to 7/16" (11mm) diameter. Schaefer 05 SS Block has 1/4" strap Shackle and a 1750 lb. safe working load.

 

Swivel Block w/ 2" Sheave: Sch 504-05:
Black Aluminum Swivel Block with 2" (50mm) diameter delrin sheave will accommodate line up to 7/16" (11mm) diameter. Schaefer 05 Block has 1/4" strap Shackle and a 1750 lb. safe working load.

 

Swivel Block w/ 2" Aluminum Sheave: Sch 504-05A:
Black Aluminum Swivel Block with 2" (50mm) diameter Aluminum sheave will accommodate wire up to 3/16" diameter and line up to 7/16" (11mm) diameter. Schaefer 05 Block has 1/4" strap Shackle and a 1750 lb. safe working load.

 


Stainless Swivel Block w/ 2 3/8" Sheave: Sch 705-05:
SS Swivel Block with 2 3/8" (60mm) diameter delrin sheave will accommodate line up to 9/16" (14mm) diameter. Schaefer 07 SS Block has 1/4" strap Shackle and a 2250 lb. safe working load.

 

Swivel Block w/ 2 3/8" Sheave: Sch 704-05:
Black Aluminum Swivel Block with 2 3/8" (60mm) diameter delrin sheave will accommodate line up to 9/16" (14mm) diameter. Schaefer 07 Block has 1/4" strap Shackle and a 2250 lb. safe working load.

 

Sch 07-05
Swivel Block w/ 2 3/8" Aluminum Sheave: Sch 704-05A:
Black Aluminum Swivel Block with 2 3/8" (60mm) diameter Aluminum sheave will accommodate wire up to 3/16" diameter and line up to 9/16" (14mm) diameter. Schaefer 07 Block has 1/4" strap Shackle and a 2250 lb. safe working load.

 


High-load Stainless Swivel Block w/ 2 3/8" Sheave: Sch 08-05:
High-load SS Swivel Block with 2 3/8" (60mm) diameter delrin sheave will accommodate line up to 9/16" (14mm) diameter. Schaefer 08 SS Block has 5/16" forged Shackle and a 2750 lb. safe working load.

 

High-load Swivel Block w/ 2 3/8" Aluminum Sheave: Sch 08-05A:
High-load SS Swivel Block with 2 3/8" (60mm) diameter Aluminum sheave will accommodate wire up to 1/4" diameter and line up to 9/16" (14mm) diameter. Schaefer 08 SS Block has 5/16" forged Shackle and a 2750 lb. safe working load.

 

Sch 08-05A

Large Stainless Swivel Block w/ 3 1/4" Sheave: Sch 10-05:
Large SS Swivel Block with 3 1/4" (82mm) diameter delrin sheave will accommodate line up to 5/8" (16mm) diameter. Schaefer Series 10 SS Block has 3/8" forged Shackle and a 3750 lb. safe working load.

 

 
Large Swivel Block w/ 3 1/4" Aluminum Sheave: Sch 10-05AX:
Large SS Swivel Block with 3 1/4" (82mm) diameter Aluminum sheave will accommodate wire up to 1/4" diameter and line up to 5/8" (16mm) diameter. Schaefer Series 10 SS Block has 3/8" forged Shackle and a 3750 lb. safe working load.

 

 


Mast Base Block Springs
Stainless Steel Springs are used to help keep Mast Base Turning Blocks upright when not under load. Used with Block Studs, Pins, Bails, and some Blocks w/ integral Threaded Studs, these Springs help prevent Blocks from hitting the Deck.
 
NG1 Mast Base Block Spring: NG1-22S:
SS spring for NG1 Mast Base Turning Blocks helps keep Blocks upright when not under load. Straight SS Spring is 25mm OD x 17mm long (uncompressed), wire is 2mm.
NG2 Mast Base Block Spring: NG2-22S:
Large SS spring for NG2 Mast Base Turning Blocks helps keep Blocks upright when not under load. Conical SS Spring is 29mm OD at the top x 40mm OD at the bottom x 50mm long (uncompressed), wire is 2.5mm.

 

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