Servicing the genoa furler drum
How to strip, clean and service a genoa furler drum so the sail rolls smoothly and safely.
The genoa furler is one of the most heavily loaded mechanisms on a sailing yacht and at the same time often neglected. It consists of a lower drum with a groove for the furling line, foils fitted over the wire forestay, and an upper swivel from which the head of the sail hangs. Most problems — stiffness when furling, the line jamming, noise — come from bearings dirty with salt and dust and from small mechanical damage. It is worth servicing every season, with a full strip-down inspection every 2–3 years.
Start by lowering the sail safely and, if possible, unstepping the mast or at least easing the forestay with temporary shrouds. SAFETY NOTE: never remove the forestay unless the mast is additionally supported — losing the forestay with the mast standing risks bringing it down. With the mast standing, limit yourself to servicing the lower drum and the swivel, without disconnecting the forestay itself. Before you undo anything, photograph the order of the washers and components.
Dismantle the lower drum as the maker's instructions say — in Selden, Furlex or Harken designs the order and the types of bearing differ considerably. The bearings in modern furlers are usually balls of plastic (Torlon, Delrin) or stainless steel running in anodised aluminium races. Clean them in warm water with detergent or in degreaser, rinse thoroughly and dry. Never grease plastic bearings with a petroleum-based grease if the maker forbids it — the plastic swells and the mechanism seizes.
Check the top swivel for axial and radial play and for free rotation. A common fault is seizing caused by the halyard wrapping round the swivel while furling — the genoa halyard must leave the swivel at the right angle, about 5–10 degrees, or it wraps and jams. If the swivel grinds or has perceptible play, consider replacing the bearing set. Check the state of the line clamp at the tack and head of the sail as well.
The forestay foils are joined at connectors, which can be a source of jamming and noise. Check that the joints have no sharp edges that could tear the sail and that the connecting screws are tight and locked. Clean and wash out the groove that guides the sail's luff tape — dust and salt increase the friction when hoisting. Remove small burrs in the aluminium gently with fine paper, taking care not to widen the groove.
Inspect the furling line over its whole length — chafe and stiffening from salt and UV reduce its strength and make it harder to handle. Check the lead blocks for the line on deck: they must lead it smoothly, with no sharp bends. Once the mechanism is back together, test it: several full furling and unfurling cycles unloaded and then under load. Smooth operation with no grinding and an even wind onto the drum are the signs of a good service.
Finally, record the service and set the stops so that a few turns of line remain on the drum when the sail is fully furled. Remember that a furler is not a device for reefing under heavy load in strong wind without easing the sheets — furling a loaded sail hard destroys the bearings and can part the line. A regular, simple service once a season is far cheaper than replacing a whole swivel or drum.
Material prices — products and options
Indicative prices in EUR (incl. VAT), as of July 2026. Products widely available in Europe; prices depend on the shop, the pack size and consumption. The links lead to example shops that ship across the EU. Dollar amounts are converted at 1 EUR = 1.1622 USD (ECB, 7 September 2026) and rounded — treat them as a rough guide, not a price in a US shop. Imperial values in brackets are conversions of the metric figure.
Degreaser / cleaner + detergent
- Yachticon — Boat Cleaner / all-purpose detergent
concentrate for washing the deck and hardware, 500 ml (17 fl oz) (budget)€9–14 (≈$10–16) - Presto / Würth — degreaser (cleaner)
spray for cleaning bearings and the foil before lubricating, 500 ml (17 fl oz) (mid-range)€8–15 (≈$9–17) - International — Super Cleaner / cleaner
degreaser before reassembly, 1 L (premium)€16–24 (≈$19–28) approx.
Lubricant for the furler (silicone / for plastic bearings)
- Seldén — Furlex Lubricant 312-501
dedicated lubricant for Furlex bearings, dispenser€20 (≈$23) - McLube — SAILKOTE dry lubricant (spray)
dry PTFE for tracks, the foil and the drum, 300 ml (10 fl oz) (mid-range)€22–30 (≈$26–35) approx. - Harken / McLube — OneDrop Ball Bearing Conditioner
conditioner for plastic (Torlon) ball bearings, small bottle (premium)€18–28 (≈$21–33) approx.
Hex / open-ended spanners (set)
- Wera / Bahco — set of hex keys (Hex-Plus)
metric 1.5–10 mm (0.06 in–0.39 in), ball-end version (mid-range)€15–30 (≈$17–35) approx. - Gedore / Stanley — set of open-ended spanners
8–19 mm (0.31 in–0.75 in), chrome vanadium steel (mid-range)€25–45 (≈$29–52) approx.
Fine abrasive paper P400–P600
- 3M — wet-and-dry paper P400/P600
sheets for rubbing down the foil and small corrections, 5 pcs (mid-range)€6–12 (≈$7–14) approx. - Mirka / Festool — set of sheets P400–P800
set of finishing grits, bulk pack (premium)€12–20 (≈$14–23) approx.
Service kit / bearings for the furler
- Seldén — Furlex 204S Lower Bearing Plugs
plastic inserts / lower bearing, a Furlex service part (budget)€35 (≈$41) - Seldén — Furlex 204S Brim Assembly
complete upper drum / flange with bearing (mid-range)€96–114 (≈$112–132) - Seldén — Furlex 204S Halyard Swivel MK2
halyard swivel with bearings, complete (premium)€854–950 (≈$993–1,104) - Harken — MKIV Torlon bearing set (spare parts)
service bearings for the MKIV drum and swivel (premium)€60–180 (≈$70–209) approx.
Thread-locking compound
- Loctite — 243 (medium strength, blue)
for stainless steel and aluminium, 10–24 ml (1 fl oz)€10–18 (≈$12–21) approx. - Loctite — 222 (low strength, for small screws)
easily undone, for hardware screws, 10 ml (0.34 fl oz)€10–16 (≈$12–19) approx.
Brushes, lint-free cloths, compressed air
- Yachticon / 3M — microfibre cloths + tack cloth
lint-free cloths for cleaning the foil, set (budget)€6–12 (≈$7–14) approx. - Set of brushes / detail brush
nylon and brass brushes for the bearings and the foil (mid-range)€5–12 (≈$6–14) approx. - Compressed air in a can (duster)
for blowing sand / salt out of the bearings, 400 ml (14 fl oz) (premium)€8–14 (≈$9–16) approx.
A new furling line
- Liros — Furling Line / Herkules 8–10 mm (0.31 in–0.39 in)
polyester braid, by the metre, chosen to suit the size of the furler (mid-range)€1.5–3.5 (≈$2–4) / m - Gleistein — Furling / Cup line 8–10 mm (0.31 in–0.39 in)
low-stretch furling line, by the metre (mid-range/premium)€2–4 (≈$2–5) / m approx. - Marlow — Doublebraid / Furling Line 8–10 mm (0.31 in–0.39 in)
strong polyester braid, by the metre (premium)€2.5–4.5 (≈$3–5) / m approx.
Complete furling systems
- Profurl — Cruising Furling System
complete genoa furling system, by forestay diameter (budget/mid-range)from €330 (≈$384) - Seldén — Furlex (furling system)
complete Furlex, model to suit the size of the yacht (mid-range/premium)from €885 (≈$1,029) - Harken — MKIV Furling System (Unit 0–2)
premium system with Torlon bearings, by unit (premium)€1200–3500 (≈$1,395–4,068) approx.