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OWNER'S MANUAL

User guide for the Selden RB and RC Mk II electric furling-mast drive on the SEL-Bus system, with or without Synchronized Main Furling (SMF): specifications, button configuration, setup, furling and unfurling, manual drive, troubleshooting, maintenance and the Mk I replacement mounting drawing.

DocumentSelden Electric Furling Mast RB & RC Mk II User Guide
FormatPDF · 20 pages · 3.8 MB
LanguageEnglish
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Owner's ManualPDF · 20 p.Mk I drive replacement – mounting instructionPDF · 2 p.
SystemConnection & SetupBefore SailingFurling & UnfurlingManual DriveTroubleshootingMk I ReplacementProducts
Selden Electric Furling Mast RB & RC Mk II — User Guide

System Overview

The drive unit (mast motor, clutch assembly, emergency gear) sits inside the mast and runs on the Selden power supply and SEL-Bus system: the mast motor connects to its own motor control unit (MCU) – furling mast; Synchronized Main Furling also needs a Selden electric winch with its MCU. Winch and all power-supply / SEL-Bus parts are sold separately. Part and serial numbers are on the aft side of the motor facing the sail groove – quote them with the mast ID in any support case.

  • Typical SMF network: battery, main switch / fuse, power supply unit (12/24V to 42V), SMF push buttons, electric winch and its MCU, winch push buttons, mast motor and its MCU, SEL-Bus backbone cables.
  • Clutch plunger: MOTOR (lower seat) or MANUAL (upper). On MANUAL, use a winch handle in the socket. The manual gear must be at FREE whenever the motor is connected.
  • Turn power off during electrical installation and whenever the system is not in use. Always watch the whole furling process and stop at once if anything goes wrong; keep clear of the sail groove, winches and moving parts.
Mast motor RB OUT RB IN RC OUT RC IN
Peak torque (Nm) 8 89 16 170
Low speed max (RPM) 49 37 37 37
High speed max (RPM) 74 74 74 74
Max power, full torque (W) 144 600 175 740
Full load current 12V / 24V (A)* – 50 / 23 – 60 / 29
Nominal current 12V / 24V (A)* – / 5,5 16 / 7,5 15 / 7,5 20 / 10

* Incl. MCU and PSU. Synchronized winch OUT limited outhaul force: RB 1800N, RC 2200N (only when driven by MAIN OUT; on winch buttons 1 and 2 the winch is neither limited nor synchronized). Mast motor and clutch assembly: H 472 mm, W 102 mm, 5,3 kg – fits inside the mast section.

Connection & Button Configuration

  • Connect the three control cables from the mast motor to the furling-mast MCU in the right positions: L1 brown, L2 orange, L3 grey. Wrong positions can damage the motor and brake. Full installation: Selden manual 597-275-E; parts: order guide 597-283-E.
  • Mast motor without synchronized winch: press the configuration button on the furling-mast MCU, then push and hold IN until the motor gives its start-up signal.
  • Synchronized Main Furling – in this order: (A) configuration button on the winch MCU, hold winch button 1 or 2 until the winch signals; (B) configuration button on the winch MCU, hold MAIN OUT until the winch signals; (C) configuration button on the furling-mast MCU, hold IN until the mast motor signals.
  • If a signal tone sounds at power-up with no button pressed, switch off at once: the push-button cables from the SEL-Bus converter must be wired normally open, not normally closed.

Preparations Before Sailing

Luff extrusion tension Torque Force F on a 10" winch handle
RB system 5 Nm 20 Nm (as printed)
RC system 8 Nm 32 Nm (as printed)
  • Correct luff-extrusion tension avoids high furling loads and wear. Hold the extrusion from turning and measure at the furling-gear winch-handle socket with a torque wrench (or spring balance and normal handle); mast straight. Without a balance, hold the extrusion by hand and turn the handle until it slips.
  • Always release backstay tension before adjusting the luff extrusion – otherwise the extrusion joints can be damaged when the backstay is eased.
  • Tune the mast with limited prebend (Selden Hints and Advice 595-540-E).
  • Outhaul car stop: start 500 mm from the aft mast wall and adjust; too far aft keeps the foot tighter than the leech and can jam the head of the sail in the mast.
  • Keep the outhaul routing low-friction and replace worn blocks: the synchronized winch limits force at the winch, so friction reduces the real clew force and hurts synchronization.

Furling & Unfurling

Manual gear at FREE, clutch plunger in the lower seat (MOTOR). Before furling either way: sail upwind, ease a very tight backstay to straighten the mast, set boom angle (kicker / topping lift) so the leech is tight and battens are parallel to the mast, ease the mainsheet. Don't reef to a point where battens ride on the sail slot.

Unfurling with synchronized winch (SMF)

  1. Secure the outhaul on the synchronized electric winch.
  2. Press OUT; the winch gives a short warning signal and starts.
  3. Hold OUT and press the second button for more speed.
  4. Full sail: keep the button(s) pressed – the system stops automatically. Reduced area: release when the sail is where you want it.
  5. Trim the outhaul with the winch buttons if needed (full winch power – take care).

Unfurling with a separate electric winch

  1. Secure the outhaul on the winch (not over-tensioned, or the motor brake may not unlock).
  2. Press OUT and wait 3 seconds.
  3. Holding OUT, press the winch button; OUT + IN together for more speed. If you let go of the mast buttons, press OUT first to resume. Don't let the winch overload the sail.
  4. Full sail: the mast motor stops by itself – release the winch button, then the mast buttons. Reduced area: release the winch button before the mast buttons.

Furling

  1. Free the outhaul but keep it tensioned (about one turn on the winch). Press IN and ease the outhaul as the sail goes in.
  2. Holding IN, press the second button for more speed.
  3. Release at the area you want or when fully furled.

The motor does NOT stop automatically when furling in: run the last turns slowly and watch the outhaul block so it isn't pulled into the sail groove.

Manual winch with electric mast motor

Hold MAIN OUT: the motor pauses unless the outhaul is pulled (so the sail can't unroll inside the mast) and turns as you pull the outhaul by hand. Releasing OUT sets the brake. At the end of unfurling the motor makes a short turn to set the brake.

Disconnecting the Motor (manual operation)

  1. Power off. Press the ratchet controller knob down and move it to IN (ratchet engaged).
  2. If there is sail load, turn a winch handle slightly clockwise to unload the clutch, then pull the clutch plunger out and up to the upper position.
  3. Furl / reef with the winch handle, ratchet at IN. To unfurl: furl fully in first to unload the ratchet, set it to FREE (turn the handle slightly clockwise if stiff), remove the handle, pull the outhaul; set back to IN and furl to the area you want.
  4. Remove the winch handle when done.

Reconnecting the Motor

  1. Pull the clutch plunger out and down to the lower position, turning the line driver by hand if needed until the clutch shaft engages.
  2. Set the furling gear to FREE – always FREE with the motor engaged.

Troubleshooting & Maintenance

Problem Cause Action
Motor stutters, unfurling doesn't work Control cables wrongly placed in the MCU Correct the cable positions (L1 brown, L2 orange, L3 grey)
Constant tone at power-up, or motor runs at power-up and stops when MAIN OUT/IN is pressed Push-button cables wired normally closed Rewire the buttons normally open
Synchronized unfurling not smooth / top of sail jams Luff tension, rig tune, outhaul car position or routing See the preparations above
Unfurling unusually slow in the cold Cold motors Disconnect the motor from the manual gear and take the outhaul off the winch; idle-run the mast motor IN at least 30 sec and the winch on high speed at least 30 sec
  • Annually: through the sail groove remove the screw over lubrication hole (A), apply WD-40 while turning the mast motor at least one turn, refit the screw. Keep the manual furling gear serviced per its own manual.
  • Every 5th year: professional service of the mast motor by an authorized Selden dealer.

Fitting the Drive to Replace a Furlin Electric Mk I (597-846)

  • Fix the drive with screws MFT10x60 in the existing holes, medium-strength locking adhesive.
  • Drill and countersink for 2x MFT10 (spacing 101 and 37 on the drawing), screw heads just below flush, medium-strength locking adhesive and marine adhesive sealant in the cover holes, with 2x support 508-495-50.
  • Starboard side: Ø20 access hole for lubrication, 215 below the reference line, distance A from the B-line; Ø20 holes for the motor support at 155,5 centres. On masts R232, R260, R290 the B-line is the centre ridge.
Mast MFT10 screw length A
F228 30 18
F246 34 22
F265 41 21
F286 46 24
F305 51 26
F324 58 25
R232 34 15
R260 40 40
R290 41 55

Need a part that isn't listed? Ask us to source it and quote the part number from the PDF.

Products in this Manual