Selden Mast Jack — Owner's Manual

Mast Jack Systems

• Kit: mast jack assembly (heel), hose garage, hand pump, tie rod assembly, mast base assembly, heel insulator (carbon masts only).
• Same height (keelson to edge of mast tube) as a standard heel plus standard adjustable mast base.
• The pump is factory set to 500 bar; D63/400 and D80/400 components are designed for max 400 bar. A separate instruction comes with the pump. All quick couplings are leakage-free.
• On furling masts the sail-compartment (middle) wall must be cut for the cylinder – contact Selden.
• Two people are needed for installation.

High loads – keep clear. Watch the rig to avoid over-tensioning: lowers and intermediates must be slack before pumping up the mast.

Replacing the Mast Heel

Tools: drill, drill bits Ø 6.5 mm and Ø 4.9-5.0 mm, hole saw Ø 28-29 mm, compass saw (C211 only), fine half-round file, pop rivet gun, Torx T30, M6 tap and tap wrench, locking adhesive (Loctite 639), silicone spray.

1. Remove the old heel (drill out the rivets with a 6.5 mm bit).
2. Cut the cable and hose exits; grind the edges.
3. Carbon masts: replace the old heel insulator with the new one supplied.
4. Cut away ~100mm of the cable conduit with a compass saw without damaging the cables.
5. C211: also cut off ~100 mm of the conduit track in the mast section.
6. Feed all electric cables out through the new cable exit (not the hose exit).
7. Insert the mast jack assembly, push the heel up / forward tight against the mast (no gap) and drill-mark the new fastener holes.
8. Remove the assembly; drill Ø 4.9-5.0 mm and tap M6.
9. Refit the assembly and lead the hose out through the hose-garage exit without trapping cables.
10. If using the hose garage, fit it (steps 12-16) before fastening the heel.
11. Clean out chips and fasten the assembly with screws and plenty of locking adhesive against corrosion.

Hose garage

1. Use the garage as a template and mark the holes, then drill 6.5 mm; insulating lacquer on contact surfaces.
2. Drill hole #1, fit a pop rivet to hold the garage, drill hole #2, rivet, and so on for all four holes.
3. Spray the hose with silicone so it slides inside the mast.
4. Feed the hose in and out of the exit hole, holding the heel close so the hose forms a bend inside the mast.
5. Rivet the garage inside the mast; the hose must enter the garage from above and slide freely.
6. Clean out chips and fasten the heel with screws and locking adhesive.

Mast Base & Tie Rod

• Mast base: remove the old base, fit the new one with the supplied washers and screws and lock it with the two grub screws. To move it, release the grub screws then the four fasteners – usually not possible once the mast is up. Tie rod bracket 508-309 needs the aft U-bolt; a mast leash needs the forward U-bolt.
• Tie rod bracket 508-309 (ref. drawing PS718; tools: Vernier caliper, 90° countersink, file or grinding pin, Torx T40, drill bits Ø 6.0-6.5 and Ø 9 mm, drill jig, Loctite 639): file ~30 mm of the pad shelf flush with the deck ring; drill two Ø 6 mm holes at c/c 20 mm (from inside the deck ring with the jig); open to Ø 9 mm; countersink for the MFT M8 heads; fit with the supplied MFT screws (short one upper) and locking adhesive; both screws should just pass through the bracket. Trim the aft deck-ring pads if needed.
• Tie rod (bracket 508-308): fork terminal to the bracket with the clevis-pin head towards the mast (tape fork and pin head to protect the mast); rigging screw to the aft U-bolt in the mast base; take up the slack before pumping the mast up.

The tools list names the drill jig 592-119/120-01, table 1 gives 529-119-01 / 529-120-01 (as printed).

Stepping, Tuning & Leash

• Fit the correct shims before stepping, thickest shims on top, secured with the supplied locking pins.
• Silicone (or Teflon) spray on the mast only – never on the deck ring or the wedge faces against the deck ring – so the mast slides on the pads.
• Keep cables and hose clear when stepping. Tune as normal (see Selden Hints and Advice): max pre-tension 25% of wire breaking strength, with all shims in place.
• Leash (some ocean racing rules): shackle to the forward mast-base U-bolt; with the mast tuned for racing (max shims) stretch it, mark the holes on the front of the mast and allow at least 5 mm extra rise.

Pressure → Load

Load → pressure tables are also printed in the manual and on top of the hand pump.