Isomat Exit Blocks

Exit Blocks incorporate a sheave, and are used to exit any internal control line (halyards, pole lifts, etc.) from a spar where a directional change of 90 to 180 degrees is required. Isomat generally uses 3 different sizes of Exit Blocks on their Mast Sections, all three attach to the mast with two (2) fasteners. Other Exit Blocks are available for replacement or exact matching purposes. See: Exit Blocks or, depending on the kind of spars you have, See also: Kenyon Exit Blocks, or Z-Spar Exit 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. For Parts for them, See Welded Mast Base Exit Boxes.

*Exit Block w/ 1 1/2" Sheave: NGA-25:* *Exit Block w/ 1 1/2" Aluminum Sheave: NGA-25A:* Exit Block is used for halyards, spinnaker pole lifts and other internal control lines. Black Plastic block assembly has removable 8mm (5/16") SS Sheave Axle. Plastic sheave is 38mm (1 1/2") diameter x 31/64" wide for rope up to 3/8" diameter. Block measures 4 1/8" long x (maximum) 1 1/16" wide and projects 1" inside of mast. Assembly fits in mast cutout 2 3/4" high x 15/16" wide, and is mounted with (2) #10 (3/16") FH fasteners on 3 3/16" (81mm) hole centers. The Aluminum Sheave version *NGA-25A* is as *NGA-25*, but with Aluminum Sheave.
*Aluminum Exit Block w/ 2" Sheave: NGA-26:* *Aluminum Exit Block w/ 2" Aluminum Sheave: NGA-26A:* Exit Block is used for halyards, spinnaker pole lifts and other internal control lines. Cast Aluminum block assembly has removable 10mm (3/8") SS Sheave Axle. Acetyl Sheave (NG1-3) is 50mm (2") OD x 14.5mm (9/16") wide for rope up to 1/2" diameter. Block measures 4 1/2" (115mm) long x 1 3/8" (35mm) wide and projects 1 7/16" (36mm) inside of mast. Assembly fits in mast cutout 2 13/16" (72mm) high x 15/16" (24mm) wide, and is mounted with (2) 1/4" (6mm) fasteners on 3 5/8" (92mm) hole centers. The stronger Aluminum Sheave version *NGA-26A* is as *NGA-26, but with Aluminum Sheave NG1-3A*.
*Large Aluminum Exit Block: NGA-27:* Internal Exit Block is used for halyards, spinnaker pole lifts and other control lines. Cast Aluminum block assembly has lightweight tubular 22mm (7/8") SS Sheave Axle. Acetyl Sheave (NG2-3W) is 85mm (3 3/8") OD x 20mm (3/4") wide for rope up to 5/8" diameter. Block measures 6 1/4" (160mm) long x 1 5/8" (41mm) wide and projects 2 7/8" (72mm) inside of mast. Assembly fits in mast cutout 4 1/2" (115mm) high x 1 1/4" (32mm) wide, and is mounted with (2) 1/4" (6mm) fasteners on 5 3/8" (136mm) hole centers. 503

Spars, Rigging, and Hardware for Sailboats