We Ship Worldwide! Shipping information.
OWNER'S MANUAL

Technical data, stay-load table, fitting, seasonal lubrication and the complete spare parts list for the Selden 174-601 mechanical backstay tensioner (250 and 400 mm stroke) and its halyard version.

DocumentSelden Backstay Tensioner Owner's Manual
FormatPDF · 4 pages · 0.3 MB
LanguageEnglish
Download PDF ▾
Owner's ManualPDF · 4 p.Spare parts list (backstay & halyard tensioner)PDF · 2 p.
Buy
SpecificationsStay LoadsFittingMaintenanceSpare PartsProducts
Selden Backstay Tensioner — Owner's Manual

Product & Technical Data

  • Mechanical tensioner for stays of 6–8 mm (10 mm under conditions below). A winch-handle bevel gear drives a bronze nut on an acid-resistant stainless threaded pull-rod connected to the backstay; the pull-rod cannot rotate (square bronze block in a square tube).
  • A safety device locks the tensioner after adjustment; you feel it as an irregularity every 3/4 of a turn.
  • Gear housing and tubes in anodised, salt-water resistant aluminium alloy.
Part No. Stroke
174-601-01 (60005) 250 mm
174-601-02 (60006) 400 mm
174-601-03 Halyard tensioner version (lower fork turned 90°)
Item Value
Maximum working load 30 000 N
Breaking load 65 000 N

10 mm backstays only if fore- and backstay are 10 mm 19-strand acid-resistant wire (or stay material with breaking strength of 88 kN or less) and the backstay-to-mast angle is at least 40 % greater than the forestay-to-mast angle.

Checking the Stay Force

  • The forestay usually makes a smaller angle to the mast (approx. 17°) than the backstay (approx. 24°), so forestay force is 30-40% greater (factor = sine of backstay angle / sine of forestay angle).
  • Continuous static load (boat not in use) should not exceed 20% of the wire breaking load; maximum static 40%. Wind and sea add roughly 25% maximum dynamic load.
Wire Ø mm Breaking load (N) Forestay contin. (N) Forestay max. (N) Backstay contin. (N) Backstay max. (N) Handle force contin. (N) Handle force max. (N) Elongation d contin. Elongation d max.
6 32000 6400 12800 4600 9200 13 35 1.4 2.8
7 43000 8600 17200 6200 12400 18 50 1.4 2.8
8 56000 11200 22400 8100 16200 30 65 1.4 2.8
10 88000 17600 35200 12720 25400 47 102 1.4 2.8
  • Backstay values use factor 1.4; measurements relate to 19-strand acid-resistant wire. Conversion: 10N = 1kp / 1kg / 2,25lb.
  • Measuring by elongation: clamp a measuring rod L = 1000 mm to the wire with a measuring stop approx. 250 mm, set d = 0 on the untensioned stay, tension and read d with a slide calliper. For 19-strand wire d = 1 mm corresponds to 10% of the breaking load.

A. Cutting the Backstay

  1. Check fore-and-aft rake and adjust if desired.
  2. Slacken the backstay rigging screw until fore- and backstay are slack.
  3. Remove the upper tube by pressing in the locking pin at its bottom edge; keep the loose parts safe.
  4. Wind the tensioner fully out (whole stroke, 250 mm or 400 mm).
  5. Lay it along the backstay with the lower pin level with the chain plate hole and mark the upper pin position on the wire.
  6. Secure the mast aft with the main halyard.
  7. Have a new swaged terminal fitted at the mark, or fit a swageless eye (Sta-lok or Norseman type) without removing the stay.
  8. Refit the shortened backstay.

B. Fitting the Tensioner

Wire Clevis pin set
Ø 6 mm Min. Ø 11 mm clevis pin + bushings
Ø 7 mm Min. Ø 13 mm clevis pin + bushings
Ø 8 & 10 mm Min. Ø 15.8 mm clevis pin (fitted when supplied)
  1. Use the largest clevis pin / hole combination the chain plate and end fitting allow; attach the tensioner to the chain plate.
  2. Remove the black conical bushing halves from the upper tube, thread the stay through (bushing end up) and connect it.
  3. Lower the tube onto the gear housing, place the bushing halves round the stay and press them in until the snap-fastener engages.
  4. Tension to the maximum value and mark the wire (paint or tape) at the top edge of the black bushing. Never go past this mark.

Continuous tension slowly deforms GRP hulls and tension drops; check the mark at the start of each season.

Maintenance & Halyard Use

  • Once a season: remove the lubricating screw on the side of the gear housing and press in grease while rotating, to reach the axial bearing and gears. Then release the upper tube, slide it up, grease the pull-rod threads and rotate so grease enters the crank chamber; refit the tube.
  • Turning the lower fork 90° (e.g. as a halyard tensioner): remove the lower tube (two screws), open the crank chamber (six screws), withdraw the fork, turn it 90°, refit and reassemble.

Spare Parts (595-303-E)

Part No. Description Dimension
174-601 Gearbox half (in kit 174-618-01 only) 150x104x36 Ask us to source it →
174-618 Gearbox half (in kit 174-618-01 only) 150x104x36 Ask us to source it →
174-604 Tension screw, 174-601-01 Ø 16-425 Ask us to source it →
174-634 Tension screw, 174-601-02/-03 Ø 16-575 Ask us to source it →
174-602 Drag link, 174-601-01 30x30-360 Ask us to source it →
174-632 Drag link, 174-601-02/-03 30x30-660 Ask us to source it →
320-007 Bevel gear (in kit 320-007-01) Ø 60x54 Ask us to source it →
320-008 Bevel gear (in kit 320-007-01) Ø 45x58 Ask us to source it →
174-605 Guide bush 30x30x45 Ask us to source it →
174-606 Guide bush 26x26x30 Ask us to source it →
174-607 Stopper 25X25x20 Ask us to source it →
174-603 Fork Ø 30x86 Ask us to source it →
174-610 Tube, 174-601-01 Ø 50/46-250 Ask us to source it →
174-630 Tube, 174-601-02/-03 Ø 50/46-550 Ask us to source it →
174-611 Tube, 174-601-01 Ø 50/46-510 Ask us to source it →
174-631 Tube, 174-601-02/-03 Ø 50/46-660 Ask us to source it →
174-608 Bush Ø 45/30-20 Ask us to source it →
174-612 Bearing (in kit 174-612-01) AXK 3552 Ask us to source it →
174-615 Washer (2; in kit 174-612-01) LS 3552 Ask us to source it →
174-617 Lip seal (in kit 174-612-01) 30x40x4 Ask us to source it →
174-609 Plug half (2) Ø 51x38 Ask us to source it →
153-001 Screw (6) M6x20 Ask us to source it →
162-051 Screw (2) M5x8 Ask us to source it →
158-011 Nyloc nut (6) M6 Ask us to source it →
158-004 Nyloc nut (2) M5 Ask us to source it →
166-534 Spring pin Ø 5x40 Ask us to source it →
166-533 Spring pin (in kit 320-007-01) Ø 5x24 Ask us to source it →
174-620 Locking knob Ø 7x13 Ask us to source it →
308-012 Spring Ø 1.0/DY7.5/L12/N4.5 Ask us to source it →
168-021 Clevis pin (2) Ø 15.8X38(HF) View part →
306-561 Flange bush (in kit 174-612-01) Ø 45/37/30-30 Ask us to source it →
308-023 Spring Ø 6x13 Ask us to source it →
539-128 Ball Ø 8 Ask us to source it →
319-582 Plug half (2) Ø 51-60 Ask us to source it →
319-681 Screw mcs 6x5 (DIN 85) Ask us to source it →
301-020 Split pin (2) Ø 3x25 (EQ.LEG) View part →
168-019 Clevis pin (2) Ø 11x40 View part →
168-015 Clevis pin (2) Ø 13x40 View part →
306-558 Flange bush (4) Ø 25/16/13-9.5 View part →

Repair kits

Part No. Kit
174-618-01 Gearbox replace kit View part →
174-612-01 Bearing repair kit View part →
320-007-01 Bevel repair kit View part →

Selden backstay tensioner 174-601 and halyard tensioner exploded view with item numbers

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

Products in this Manual