Fireball Tuning Guide by Sailboats Speedsails

The Fireball is quite a complicated boat and so getting the rig properly calibrated and clearly marked will make sailing the boat fast through the changing wind conditions and sea states a much easier task. These measurements are based on a 2:1 jib halyard.

Spreader Settings

Setting	Proctor	Superspar M7
Spreader Length (L)	425mm	420mm
Spreader Deflection (D)	125mm	145mm

Pre-Bend

The pre-bend is the most important part of the set up. We set the pre-bend with the mast rake at 22' 8" and a rig tension of 400lbs on the luff of the jib. The bend is then set at 27mm, measured by holding the main halyard tight to the top of the gooseneck and then measuring the distance between the wire and the back of the mast at spreader height. The spreader deflection is only a rough starting point and may require alteration to get the bend right.

Mast Rake

Mast rake is measured from the top of the mast to the top of the transom in the centreline of the boat. When the tape is at the top of the mast the distance to the black band at the gooseneck should be 18' 9".

Conditions	Mast Rake
Both in the boat – high trapezing	22' 8" (400lbs rig tension)
Consistently overpowered – flapping the mainsail upwind	22' 6" (400lbs rig tension). For Cumulus masts: turn spreaders out one full turn when raking from 22'8" to 22'6"
Consistently overpowered – racing abandoned	22' 4" (400lbs rig tension)

Strut

Conditions (Beaufort)	Strut Setting
Force 0–1	Pull the mast forward to help flatten the bottom of the mainsail
Force 1–2	Pull slightly back behind neutral to power up the bottom of the main (neutral = where the mast sits naturally with rig tension on but no extra forces)
Force 2–4	Fix in its neutral position
Force 4+	Ease off gradually as you become more overpowered

Jib Bars

This is a very critical area of the set up as it controls the slot between the main and the jib. The following settings correspond to the mast rake settings above.

Setting	Bar Position (from centreline)	Bar Height
	250mm	Leave up — keeps sail flat with open leech. Top tell-tale should just break first.
Mainsheet on centreline	250mm	Pull down — adds power to the bottom of the sail. As mainsheet is eased, move bars to 260mm.
Fully overpowered	Ease to 270mm	Slowly ease pulleys back up to flatten the bottom of the sail and open the leech

Jib Cunningham

This should be set to just remove creases from the front of the sail. As the wind increases more tension will be required.

Centreboard

With the board at right angles to the bottom of the boat, mark a line '0' on the head of the board, then put marks at 1" intervals down the board.

Setting	Centreboard Position
	1" forward of vertical
Not yet planning	Vertical. As you begin to plane, raise the board 2"
Overpowered	Raise 3–4" in flat water; up to 6" in big seas to stop the boat tripping over itself

Cunningham

Only use the cunningham once you become overpowered. As you have to ease the main, adding a little cunningham will help flatten the main. In heavy airs pull it quite hard to open the leech. As the wind lulls, the first thing to do to power up the rig is to ease the cunningham.

Kicker

Until you have to ease the main the kicker should only have the slack taken out of it. Above this wind strength ensure there is enough kicker tension to keep the top tell-tale flying approximately 80% of the time. Remember to let the kicker off at the windward mark.

Outhaul

Point of Sail	Outhaul Setting
Upwind	Pull tight
Downwind (long broad reaches)	Ease ~2" to power up the bottom of the main

Spinnaker

90% of the time the key to setting the spinnaker correctly is to ensure both the tack and the clew are level. If it breaks high then the pole is too high and vice versa. If the wind drops so that you are struggling to set the spinnaker, dropping the pole a few inches will support it and help it set.