How do I adjust mast rake and rig tension on an Albin Delta 31?
I'm setting up the rig on my Albin Delta 31 after stepping the mast, and the leeward shrouds look loose when beating. How should I set the mast rake and shroud tension, and how much weather helm should I aim for?
Answer
Set your Albin Delta 31's mast straight athwartships, with slight aft rake and controlled forward prebend, then adjust rake under sail for light weather helm. Set shroud tension with a gauge and check it under sail: the leeward shrouds should remain tensioned close-hauled, and the mast should stay straight sideways.
Check the rig
Identify the mast, spreader arrangement and standing rigging fitted to your boat. Replacement spars, altered chainplates and different wire sizes mean another Delta 31's turnbuckle settings may not suit yours. Record the existing settings before changing them.
Inspect the mast step, compression support below it, chainplates, spreader roots, terminals and turnbuckles. Fix structural movement or cracked terminals before adding tension. Tightening the rig puts more load on the fault.
Keep the mast supported by its stays throughout adjustment. Never disconnect a loaded forestay or move a loaded mast heel.
- Have a steel tape, a rig tension gauge matched to the wire diameter and construction, suitable spanners, fresh split pins and rigging tape.
- Check that turnbuckles have adequate thread engagement at both ends and that their studs can articulate without bending.
- Mark the current turnbuckle positions and note exposed thread lengths, wire diameters and gauge readings.
A Loos or comparable gauge is useful, but its scale must match your wire. There is no universal turnbuckle torque setting: thread condition and lubrication affect the reading too much.
Centre the mast
Work afloat in calm water with normal cruising loads aboard. Ease the mainsheet, kicker and adjustable backstay so they do not distort the starting measurement. Keep all standing rigging connected.
- Use the main halyard under consistent tension to compare distances to matching port and starboard chainplate pins. Adjust the cap shrouds until the measurements agree.
- Sight up the mainsail track from the gooseneck. Adjust the lower shrouds to remove sideways bends while retaining the intended fore-and-aft curve.
- Hang a weight from the main halyard and measure its distance aft of the mast at a repeatable height, with the weight damped in a bucket of water. Record the boat's fore-and-aft trim too.
The plumb-line measurement lets you repeat and compare settings; it is not a factory rake specification. Without an original tuning sheet for your particular spar, start with slight aft rake rather than an unsupported millimetre target.
Forestay length is the normal rake adjustment. Lengthening it generally increases aft rake; shortening it brings the mast more upright. Mast-foot position also affects geometry, but move it only if the installation is designed for adjustment and the rig is properly unloaded.