GP14 Kicker (Vang) Tuning & Trim Guide
Master Mast Bend and Leech Control
1. What the Kicker Does
The kicker is your primary sail power and leech control once the mainsheet is loaded. It affects mast bend, mainsail leech tension, and boom height.
Simple summary:
| Kicker tension | Effect |
|---|---|
| More kicker | Bends mast, flattens main, tightens leech → depower |
| Less kicker | Straightens mast, fuller main, open leech → more power |
2. Mechanical Setup
Most GP14s use:
- Cascade kicker system (12:1 to 16:1 purchase) led to each side of the centreboard case
- Must run smoothly — any friction makes fine trimming difficult
- Use high-quality ball-bearing blocks (Allen, Harken, Ronstan) and Dyneema control lines
Check:
- • Kicker leads directly from boom to mast base, no twists
- • Cleats hold firmly but can release instantly in gusts
- • You can adjust easily from the helm hiking position
3. What the Kicker Controls
| Function | Effect |
|---|---|
| Boom height | Stops the boom lifting off downwind or in gusts |
| Leech tension | Controls main twist and pointing ability |
| Mast bend | Flattens main and opens leech when pulled on |
| Forestay tension | Tight kicker bends mast → increases forestay tension slightly |
| Jib slot shape | Indirectly affected by mast bend (flatter main opens slot) |
4. Kicker Settings by Wind Strength
| Wind | Setting | Result |
|---|---|---|
| Light (<8 kt) | Very light — just enough to stop boom bouncing | Full, powerful main; leech open for flow |
| Medium (8–14 kt) | Moderate — boom just below midline | Balanced twist and power |
| Fresh (14–18 kt) | Firm — boom near centreline, leech controlled | Flattened main, depowered but driving |
| Heavy (>18 kt) | Hard — maximum bend, boom low, leech tight | Depowered, flat sail; easy to keep boat upright |
5. Interaction With Other Controls
| Control | Combined Effect | Tuning Tip |
|---|---|---|
| Outhaul | Both flatten the main | If you add kicker, you may ease outhaul slightly to regain foot depth |
| Cunningham | Both depower; kicker bends mast, cunningham tensions luff | Add together in breeze for best control |
| Chocks (mast gate) | Kicker bends mast aft; if too soft, mast over-bends | Remove front chock if overpowered; replace if sail too flat |
| Spreader deflection | Determines how much mast can bend under kicker load | Check deflection before relying on kicker power |
| Mainsheet | Adds leech tension too; kicker lets you separate sheet (angle) from leech control | Use mainsheet to steer power, kicker to set base leech tension |
6. Visual Cues — What to Look For
| Sail Observation | Meaning | Adjustment |
|---|---|---|
| Leech fluttering / twisty | Too little kicker | Pull on more kicker |
| Upper leech closed / top telltale stalled | Too much kicker | Ease slightly |
| Boat heels violently in gusts | Leech too tight, mast too straight | Remove chock or ease kicker |
| Boat slow and underpowered | Leech too open | Add kicker to hold boom down |
| Main backwinding from jib | Mast too straight, no kicker | Add kicker or increase chock preload |
7. How to Trim Underway
Upwind:
- • Use kicker to set leech tension so top telltale flicks occasionally
- • Adjust kicker when gusts build instead of constantly changing mainsheet tension
- • Watch the top batten: it should be roughly parallel with the boom when powered up
In Gusts:
- • As wind increases, pull on more kicker to flatten sail and reduce twist
- • When easing mainsheet in gusts, keep kicker firm so boom stays controlled
Downwind:
- • Ease kicker substantially so the boom can rise and the sail twist open
- • If kicker is too tight, boom tip can hit the water and cause a windward capsize
- • Boom should just stay above the gunwale, not drooping into waves
8. Typical Range (feel-based)
| Condition | Tension Feel | Indicator |
|---|---|---|
| Light | Loose, just tensioned | Boom floats but doesn't bounce |
| Medium | Firm but movable by hand | Boom sits steady, top leech telltale streaming |
| Fresh | Very firm, requires purchase effort | Boom controlled, top telltale just flicking |
| Heavy | Maximum tension | Boom locked, mast visibly bending |
9. Coordination with Rig Tune
| Mast Tune | Kicker Usage | Comment |
|---|---|---|
| More rake (pins down) | Needs more kicker | Mast further aft, boom angle changes |
| Less rake (pins up) | Needs less kicker | Mast upright, less leverage |
| More deflection (soft rig) | Less kicker needed | Mast bends easily |
| Less deflection (stiff rig) | More kicker needed | Stiffer mast needs more load for same bend |
10. Troubleshooting
| Problem | Cause | Solution |
|---|---|---|
| Boat feels dead after gust | Too much kicker (mast over-bent) | Ease kicker slightly |
| Boom jumps on waves downwind | Not enough kicker | Add a bit of kicker |
| Boat slow to point | Leech too open | Add kicker |
| Boat rounds up in gusts | Leech too tight | Ease kicker or remove front chock |
| Sail wrinkles near luff upwind | Not enough cunningham with kicker load | Add cunningham to match bend |
11. Safety Tip
In strong wind gybes — ease kicker before gybing.
If kicker stays tight, boom can't rise and will slam violently → risk of capsize or boom hitting water.
12. Quick Reference Summary
| Wind | Kicker | Outhaul | Chocks | Cunningham |
|---|---|---|---|---|
| Light | Just taut | Eased 40–50 mm | 2 front | None |
| Medium | Moderate | 15–25 mm | 1 front | Just on |
| Fresh | Firm | 0–10 mm | None / 1 behind | On |
| Heavy | Very firm | Tight | None / 1–2 behind | On hard |
13. Key Takeaways
The kicker is your main mast-bending control on a GP14
Upwind: sets leech tension and mast bend
Downwind: must be eased to avoid capsize
Coordinate with outhaul, chocks, and cunningham for balance
Use visual cues: top batten ≈ parallel to boom for correct tension
Mark your kicker control line for light / medium / heavy settings