Isomat Fractional Jib Boxes

FM 0 Fractional Jib Boxes & Components FM0 Fractional Jib Boxes use 40mm (1 9/16") sheaves for up to 5/16" (8mm) line and are commonly used on FM-101 and smaller Mast Sections.
*WE Double Jib Box Ass'y w/ Stemball Socket: FM0-30A:* Cast aluminum two (2) halyard internal Jib Box Assembly with Stemball Socket for Fractionally rigged Masts. Accommodates two (2) Jib halyards up to 5/16" (8mm) diameter, and features a 20mm Stemball Socket for Forestay attachment. Assembly uses (2) 40mm (1 9/16") Delrin Sheaves, FM0-3, for Jib halyards on an 8mm Axle, FM0-6L. Assembly fits in mast cutout 3" (76mm) high x 1 1/2" (37mm) wide. Assembly is designed to fit through the mounting slot and is then pulled down, a screw or rivet is then installed above the casting to keep it locked in place. Unit measures (maximum) 3 7/8" long x 1 11/16" wide and projects 1 1/4" (maximum) inside of mast. 'WeekEnder' Jib Box is commonly used on FM-35 thru FM-101 Mast Sections.
	FM0 Jib Box Sheave: FM0-3: Black Delrin Sheave is 40mm (1 9/16") OD x 10mm (3/8") wide x 8mm (5/16") ID. Used for Jib halyard sheaves in FM0-30A Jib Box. SM40R10-8
	FM0 Jib Box Sheave Axle: FM0-6L: SS 'Drop-in' Sheave Axle pin is 8mm (5/16") dia. x 31mm (1 1/4") long. Used for Sheave Axle in FM0-30A Jib Box.


NG 1 Fractional Jib Boxes & Components NG1 and FM1 Fractional Jib Boxes use up to 60mm (2 5/16") sheaves for up to 7/16" (11mm) line and are commonly used on NG-51, FM-305 and smaller Mast Sections.
*NG1 Jib Box Ass'y w/ Toggle - 8mm Pin: NG1-30A:* *NG1 Jib Box Ass'y w/ Toggle - 10mm Pin: NG1-31A:* *NG1 Jib Box Ass'y w/ Toggle - 12mm Pin: NG1-32A:* *NG1 Jib Box - Casting Only: NG1-30:* Cast aluminum two (2) halyard internal Jib Box Assembly with Forestay Toggle for Fractionally rigged Masts. Accommodates a single Jib halyard below the Toggle and a Spinnaker halyard over the Toggle. Toggle is shielded by contoured nose to minimize chafe on Spinnaker halyard. Assembly uses (2) 60mm (2 5/16") Acetyl Sheaves (NG1-4), on (2) 10mm Axles, (NG1-6S). Sheaves are suitable for use with wire or rope halyards up to 7/16" diameter. Assembly fits in mast cutout 5 5/8" (143mm) high x 1 3/16" (30mm) wide. Internal mounting flange is slightly curved to fit a variety of mast sections. Assembly is designed to fit through the mounting slot and is then fastened from the outside with (1) 6mm machine screw which threads into locknut held in casting (machine screw and locknut included). Stainless Steel Toggle (in various pin sizes) is included. Unit measures (maximum) 6 5/8" long x 1 1/2" wide and projects 2 1/2" (maximum) inside of mast. Suitable for use with a variety of mast sections on boats with forestays up to 1/4" or 7mm diameter. Other Pin sizes (5/16" - 1/2") are available, please specify.
*NG1 Double Jib Box Ass'y w/ Toggle - 8mm Pin: NG1-30DA:* *NG1 Double Jib Box Ass'y w/ Toggle - 10mm Pin: NG1-31DA:* *NG1 Double Jib Box Ass'y w/ Toggle - 12mm Pin: NG1-32DA:*
Cast aluminum three (3) halyard internal Jib Box Assembly with Forestay Toggle for Fractionally rigged Masts. As NG1-30A, above, but with two (2) wire Jib halyard Sheaves, NG1-4NS, (5/32" (4mm) maximum) below the Toggle. Other Pin sizes (5/16" - 1/2") are available, please specify.
	NG1 Forestay Toggle w/ 8mm Pin: NG1-30-8T: NG1 Forestay Toggle w/ 10mm Pin: NG1-30-10T: NG1 Forestay Toggle w/ 7/16" Pin: NG1-30-11T: NG1 Forestay Toggle w/ 12mm Pin: NG1-30-12T: SS Toggle only for use with a variety of NG1 Fractional Forestay Attachments. Formed SS Toggle is (minimum) 14mm wide x 4mm thick and approximately 58mm (2 1/4") between Pin centers. Other Pin sizes (5/16" - 1/2") are available, please specify.
	Sheave for NG1 Jib Box: NG1-4: Factory standard Acetyl Sheave is 60mm (2 5/16") OD x 14mm (9/16") wide x 10mm (3/8") ID. Used in all NG1 cast Jib Box Assemblies.
	Aluminum Sheave for NG1 Jib Box: 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. Especially recommended for use with wire or small diameter line.
	NG1 Jib Box Sheave Axle: NG1-6S: SS 'Drop-in' Sheave Axle pin is 10mm (3/8") diameter x 22mm (7/8") long. Used for all Sheaves in all NG1 Cast Jib Boxes.
	NG1 Double Jib Box Narrow SS Sheave: NG1-4NS: Special Narrow Stainless Steel Sheave is 60mm (2 5/16") OD x 6mm (1/4") wide x 10mm (3/8") ID. Used for Jib sheaves in NG1 Cast Double Jib Box Assembly. SS Sheave is suitable for use with wire halyards up to 5/32" diameter.
	NG1 Double Jib Box Sheave Washer: NG1-4NSW: Special Teflon Sheave Washer is 60mm (2 5/16") OD x 10mm (3/8") ID. Used on each side of SS Narrow Jib sheaves in NG1 Cast Double Jib Box Assembly.
	NG1 Double Jib Box Sheave Separator: NG1-30DS: Stainless Steel Sheave Separator for use in NG1 Cast Double Jib Box Assembly. SS Plate locks into integral notches in casting between the 2 Jib (lower) sheaves and has a 10mm (3/8") hole for the sheave axle.

*FM1 Jib Box Ass'y w/ Toggle - 8mm Pin: FM1-30-8A:* *FM1 Jib Box Ass'y w/ Toggle - 10mm Pin: FM1-30-10A:* *FM1 Jib Box Ass'y w/ Toggle - 12mm Pin: FM1-30-12A:* Cast aluminum three (3) halyard internal Jib Box Assembly with Forestay Toggle for Fractionally rigged Masts. Accommodates two (2) Jib halyards below the Toggle and a Spinnaker halyard over the Toggle. Assembly uses NG1-3 and *NG1-4* Sheaves for the Jib Halyards, and NG1-3 and SM40-15-10 Sheaves for the single Spinnaker Halyard. Easily replaceable internal sheaves ride on 10mm Axles, FM1-30KP. Sheaves are suitable for use with halyards up to 7/16" diameter. Unit fits in mast cutout 7 1/2" (190mm) high x 1 3/16" (30mm) wide. Assembly is designed to fit through the mounting slot and is then fastened from the outside with (2) 6mm (1/4") screws or rivets. Stainless Steel Toggle (in various pin sizes) is included. Casting measures (maximum) 240mm (9 1/2") long x 35mm (1 3/8") wide and projects 85mm (3 3/8") (maximum) inside of mast. Suitable for use with a variety of mast sections on boats with forestays up to 1/4" or 7mm diameter.
	NG1 Forestay Toggle w/ 8mm Pin: NG1-30-8T: NG1 Forestay Toggle w/ 10mm Pin: NG1-30-10T: NG1 Forestay Toggle w/ 12mm Pin: NG1-30-12T: SS Toggle only for use with a variety of NG1 Fractional Forestay Attachments. Formed SS Toggle is (minimum) 14mm wide x 4mm thick and 58mm (2 1/4") between Pin centers. Other Pin sizes (5/16" - 1/2") are available, please specify.
	FM1 Jib Box Sheave, 50mm: NG1-3: Factory standard Acetyl Sheave is 50mm (2") OD x 14mm (9/16") wide x 10mm (3/8") ID. Used as upper and lower internal Sheaves in FM1 cast Jib Box Assemblies.
	FM1 Jib Box Sheave, 50mm - Aluminum: NG1-3A: Anodized Aluminum Sheave is 50mm (2") OD x 14mm (9/16") wide x 10mm (3/8") ID, and is much sturdier than the plastic version.
	FM1 Jib Box Sheave, 60mm: NG1-4: Factory standard Acetyl Sheave is 60mm (2 5/16") OD x 14mm (9/16") wide x 10mm (3/8") ID. Used as center Sheave in FM1 cast Jib Box Assemblies.
	FM1 Jib Box 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.
	FM1 Jib Box Sheave Axle: FM1-30KP: Knurled SS Sheave Axle pin is 10mm (3/8") diameter x 28mm (1 1/8") long. Used for all 3 internal Sheaves in all FM1 Cast Jib Boxes.

NG 2 Fractional Jib Boxes & Components NG2 Fractional Jib Boxes use 85mm (3 3/8") sheaves for up to 5/8" (16mm) line and are commonly used on NG-60, FM-385 and larger Mast Sections.
*NG2 Jib Box Ass'y w/ Toggle - 12mm Pin: NG2-30-12A:* *NG2 Jib Box Ass'y w/ Toggle - 14mm Pin: NG2-30-14A:* *NG2 Jib Box Ass'y w/ Toggle - 16mm (5/8") Pin: NG2-30-16A:* *NG2 Jib Box - Casting Only: NG2-30:*
Cast aluminum Jib Box and Forestay Toggle Assembly is designed to be welded in Mast Section. Unit provides a single sheave for an internal Jib or Staysail halyard up to 5/8" diameter and a secure attachment point for Forestays up to 3/8" (10mm) diameter. Assembly uses an 85mm (3 3/8") Acetyl Sheave (NG2-4-16) on a 16mm Axle, (NG2-6B). Toggle mounts on removable 19mm Clevis Pin which can be used to mount optional Spinnaker halyard Spectacle Assembly (NG2-31S), below. Unit fits in mast cutout 7 5/8" (195mm) high x 1 3/8" (35mm) wide. Assembly is designed to fit through the mounting slot and is then welded from the outside. Casting measures (maximum) 230mm (9") long x 46mm (1 3/4") wide and projects 70mm (2 3/4") (maximum) inside of mast. Suitable for use with a variety of mast sections on boats with forestays up to 3/8" or 10mm diameter. Stainless Steel Toggle with Pin (in various pin sizes) is included.
	NG2 Jib Box Sheave: NG2-4-16: Acetyl Sheave is 85mm (3 3/8") OD x 20mm (3/4") wide x 16mm (5/8") ID.
	NG2 Jib Box Sheave Axle: NG2-6B: SS 'Drop-in' Sheave Axle pin is 16mm (5/8") diameter x 29.5mm (1 5/32") long. 1104
	*NG2 Jib Box Toggle, 12mm Pin: NG2-30-12T:* *NG2 Jib Box Toggle, 14mm Pin: NG2-30-14T:* *NG2 Jib Box Toggle, 16mm (5/8") Pin: NG2-30-16T:* Stainless Steel Forestay Toggle for use with NG2 Cast Jib Box. Toggle rides on 19mm Pin in casting, lower Clevis pin (in various sizes) is included. Other Pin sizes (1/2" - 5/8") are available, please specify.
	*NG2 Jib Box Toggle Attachment Pin: NG2-30P:* SS Clevis Pin is used in NG2 Cast Jib Box for attachment of Forestay Toggle. Clevis Pin is 19mm (3/4") diameter with a 52mm (2 1/16") grip length. Single Pin is also used for attachment of optional Spinnaker halyard Spectacle Assembly (NG2-31S), below. CPM19-52
	*NG2 Jib Box Spinnaker Spectacles: NG2-31S:* Optional SS Spectacle Assembly for NG2 Cast Jib Box allows for two (2) Spinnaker halyards and mounts easily on Jib Box Toggle Pin. Cast Stainless 'eyes' are smoothly faired to minimize chafe on halyards up to 1/2" diameter. Spinnaker halyards exit mast through staggered Exit Blocks mounted several feet above Jib Box Assembly and go straight down through Spectacle 'eyes' and forward. 562109

NG 2 Extruded Fractional Jib Boxes & Components NG2 Extruded Fractional Jib Boxes are designed to be welded in Mast Section. Extruded Fractional Jib Box uses (2) 85mm (3 3/8") sheaves in a side by side configuration. Sheaves are suitable for up to 1/2" (12mm) line and are commonly used on NG-60, FM-385 and larger Mast Sections.
*NG2 Double Jib Box Ass'y w/ Toggle - 8mm (5/16") Pin: NG2-32-08A:* *NG2 Double Jib Box Ass'y w/ Toggle - 10mm Pin: NG2-32-10A:* *NG2 Double Jib Box Ass'y w/ Toggle - 12mm Pin: NG2-32-12A:* *NG2 Double Jib Box Ass'y w/ Toggle - 14mm Pin: NG2-32-14A:* NG2 Double Jib Box Ass'y w/ Toggle - 16mm (5/8") Pin: NG2-32-16A:
Extruded aluminum Double Jib Box and Forestay Toggle Assembly is designed to be welded in Mast Section. Unit provides two (2) sheaves for internal Jib or Staysail halyards up to 5/8" diameter and a secure attachment point for Forestays up to 3/8" (10mm) diameter. Assembly fits in 4 7/16" high x 1 13/16" wide slot, and uses 85mm (3 3/8") Acetyl Sheaves (NG2-3B10) on a 10mm Axle. Axle slides in through a hole in the side of the Mast, hole is covered with a SS Cover Plate. Toggle mounts on removable 14mm Clevis Pin (CPM 14-46). Stainless Steel Toggle with Pin (in various pin sizes) is included. Other Pin sizes between 10mm and 16mm are available, please specify. B=202304
	Sheave for NG2 Double Jib Box: NG2-3B10: Acetyl Sheave with precision pressed Delrin bushing is 85mm (3 3/8") x 15mm (5/8") wide x 10mm (3/8") ID.
	Sheave Axle for NG2 Double Jib Box: NG2-32SAP: SS Pin is used in NG2 Double Jib Box as Sheave Axle. Straight Pin is 10mm (3/8") diameter x mm (") long.
	*NG2 Double Jib Box Toggle, 8mm Pin: NG2-32-08T:* *NG2 Double Jib Box Toggle, 10mm Pin: NG2-32-10T:* *NG2 Double Jib Box Toggle, 12mm Pin: NG2-32-12T:* *NG2 Double Jib Box Toggle, 14mm Pin: NG2-32-14T:* *NG2 Double Jib Box Toggle, 16mm (5/8") Pin : NG2-32-16T:* Stainless Steel Forestay Toggle only, for use with NG2 Double Jib Box. Slotted Toggle rides on 14mm Pin, lower Clevis pin (in various sizes) is included. Other Pin sizes (3/8" - 5/8") are available, please specify. Toggle is 35mm wide with 65mm between pin centers, and will accommodate eyes up to 16mm (5/8") thick. Slot is 7mm wide x 50mm deep.
	*NG2 Double Jib Box Toggle Attachment Pin: NG2-32TP:*
	SS Clevis Pin is used in NG2 Double Jib Box for attachment of Forestay Toggle. Clevis Pin is 14mm (9/16") diameter with a 52mm (2 1/16") grip length. CPM14-52

Your cart

Spars, Rigging, and Hardware for Sailboats