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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 NG1 Fractional Masthead


The NG1 Fractional Rig Masthead is commonly used on Isomat Fractional Masts using the NG-28 through NG-51 (tapered and untapered) Mast Sections, See: NG Mast Sections.
Larger NG Mast Sections use a welded semi-custom Fractional Masthead.
For NG1 Masthead Rig Mastheads, See: NG1 Masthead.
 


NG1 Fractional Masthead Parts
NG1 Fractional Masthead Assembly - Complete: NG1-1FAC:
The NG1 Fractional Rig Masthead Assembly is a single casting, NG1-1FB, welded to the Mast Section which allows for 2 Main halyards (or 1 Halyard and a topping lift) using a single 'Drop-in' Sheave Axle, NG1-6, and (2) 60mm Sheaves, NG1-4. Masthead Cover Plate, NG1-1F, keeps Sheaves and Axle in place. Masthead includes provisions for attachment of a Backstay, and (2) Upper shrouds (rarely used) using Stemball rigging fittings. Commonly used on NG-28 through NG-51 Mast Sections.

 

 

  NG1 Fractional Masthead Body: NG1-1FB:
The NG1-1FB Fractional Masthead Body is a single casting welded into the Mast Section. The main frame for the NG1-1FAC Fractional Masthead Assembly, the NG1 Fractional Masthead Body is (maximum) 5 1/16" (130mm) wide x 10" (255mm) long (on top).

 

NG1 Fractional Masthead Cover Plate - Standard: NG1-1F:
Cast aluminum Masthead Cover Plate for NG1 Fractional Rig Masthead. Masthead Cover Plate also serves as Sheave separator, provides level surface for mounting Anchor light, and has slots for exiting other electrical wires. Standard Cover Plate is 2 11/16" (maximum) wide x 6 1/4" long (on top) and is fastened with one (1) 6mm screw going through the front of the mast. Note: Older NG1 Fractional Rig Mastheads used different (non-compatible) Cover Plates, listed below.

 

NG1 Masthead Sheave, 60mm: NG1-4:
Factory standard Acetyl Sheave is 60mm (2 5/16") OD x 14mm (9/16") wide x 10mm (3/8") ID.

 

NG1-4
  NG1 Masthead Sheave, 60mm Aluminum: NG1-4A:
Anodized Aluminum Sheave is 60mm (2 5/16") OD x 14mm (9/16") wide x 10mm (3/8") ID, and is much sturdier than the plastic version.

 

 
NG1 Masthead Sheave Axle: NG1-6:
SS 'Drop-in' Sheave Axle pin is 10mm (3/8") diameter x 40.8mm (<1 5/8") long. Used for all Sheaves in all NG1 Mastheads.

 

NG1-6

NG1 Fractional Masthead Cover Plate - Old-style: NG1-1FX:
Masthead Cover Plate for Old-style NG1 Fractional Rig Masthead. Cast aluminum Cover Plate also serves as Sheave separator, provides level surface for mounting Anchor light, and has a hole for exiting electrical wires. Old-style Cover Plate is 2 7/8" (maximum) wide x 6 1/4" long (on top) and is fastened with one (1) 6mm screw going through the front of the mast.    802152

 

 

 

NG1 Fractional Masthead Cover Plate - Old-style - Long: NG1-1FXL:
Masthead Cover Plate for Old-style Long NG1 Fractional Rig Masthead. Cast aluminum Cover Plate also serves as Sheave separator, provides level surface for mounting Anchor light, and has a hole for exiting electrical wires. Old-style Cover Plate is 2 7/8" (maximum) wide x 7 1/4" long (on top) and is fastened with one (1) 6mm screw going through the front of the mast.    802153
 
 

 


NG1 Stemball Cup Washer - 26x11: NG1-CW11:
Standard NG1 Stemball Cup Washer is used with swage and mechanical Stemballs in NG1 Mastheads, Spreader Bases, some Stemball Backing Shells, and in other applications. Type 316 SS Cup Washer is 26mm (>1") OD x 11mm (7/16") ID x 11.5mm (7/16") high. For use with 5/32", 3/16", 7/32", 4mm, and 5mm Standard Swage Stemballs, and 5/16", 3/8", and 7/16" threaded Stemballs.

 

NG1 Stemball Cup Washer - 26x13: NG1-CW13:
Standard NG1 Stemball Cup Washer is used with swage and mechanical Stemballs in NG1 Mastheads, Spreader Bases, some Stemball Backing Shells, and in other applications. Type 316 SS Cup Washer is 26mm (>1") OD x 13mm (>1/2") ID x 11.5mm (7/16") high. For use with 7/32", and 5mm Standard Swage Stemballs, and 7/16" threaded Stemballs.

 

 
NG1 Stemball Cup Washer - 26x16: NG1-CW16:
Standard NG1 Stemball Cup Washer is used with swage and mechanical Stemballs in NG1 Mastheads, Spreader Bases, some Stemball Backing Shells, and in other applications. Type 316 SS Cup Washer is 26mm (>1") OD x 16mm (5/8") ID x 11.5mm (7/16") high. For use with 1/4", 9/32", 6mm, and 7mm Standard Swage Stemballs, and 1/2", threaded Stemballs.

 

Swage Stemballs for Imperial Wire
Swage Stemball for 5/32" Wire: RS-SB-M4:
Swage Stemball for 3/16" Wire: RS-SB-3/16:
Swage Stemball for 7/32" Wire: RS-SB-7/32:
Swage Stemball for 1/4" Wire: RS-SB-1/4:
Swage Stemball for 9/32" Wire: RS-SB-M7:
Standard NG1 Stemball Swage is used with Imperial (US Standard) 1x19 wire and appropriate Stemball Cups in NG1 Mastheads, Spreader Bases, some Stemball Backing Shells, and in other applications.

 

 

Stainless Steel Stemball Terminal

Swage Stemballs for Metric Wire
Swage Stemball for 4mm Wire: RS-SB-M4:
Swage Stemball for 5mm Wire: RS-SB-M5:
Swage Stemball for 6mm Wire: RS-SB-M6:
Swage Stemball for 7mm Wire: RS-SB-M7:
Standard NG1 Stemball Swage is used with Metric 1x19 wire and appropriate Stemball Cups in NG1 Mastheads, Spreader Bases, some Stemball Backing Shells, and in other applications.

 

 

Stainless Steel Stemball Terminal

NG1 Stemball / Eye Adapter for 3/8" (or 10mm) Pin: NG1-SBE-6:
NG1 Stemball / Eye Adapter for 7/16" (or 11mm) Pin: NG1-SBE-7:
NG1 Stemball / Eye Adapter for 1/2" (or 12mm) Pin: NG1-SBE-8:
SS NG1 Stemball / Eye Adapters have a 26mm (>1") head diameter. Length from base of Stemball to Pin center is 4" (100mm), or 4 1/4" (108mm) on 1/2" size. A variety of other NG1 Stemball / Eye Adapters are available with or without a Toggle, See: NG1 Stemball / Eye Adapters.

 


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