470 Tuning Guide

Our 470 tuning guide is intended for you to be able to set up your rig with the minimum of fuss. As long as you follow the simple rules in this guide you will have immediate 'pace' and an excellent base from which to fine tune and develop new ideas.

Mast Step

Measured from the inside of the transom to the centre of the mast heel. Measurement 3120mm.

Spreaders

Length is measured from side wall of mast to the shroud.

To measure deflection place the top batten (or any straight edge) across the tips of the spreaders and then measure to the mast off the straight edge.

Rig Tension

36 - 38 Loo's meter, measured at shoulder height on jib luff.

Mast Rake

Measured with no mast puller and a rig tension of 36 on Loo's tension meter. Attach long tape measure to the main halyard, pull to black band on top of the mast and measure to top of transom.

NOTE: If caught out by a change in wind strength, then rig tension can be eased or increased accordingly to min/max tension to get closer to ideal rake.

Measurements on Ziegelmyer 470 deduct 20mm/3/4'' compensates for curve on transom.

Mast Puller

This controls the amount of bend in the mast, particularly in the lower quarter. It affects the power in the rig and is critical to boat speed.

The table below shows the amount of puller needed from a base point of neutral.

Pre Bend

Measured at spreader height with main halyard held at gooseneck level:

55mm / 2 1/4"

Centreboard

The leading edge of the C/B should be angled forwards in light air and gradually raised as wind picks up. In medium airs it should be vertical. In heavy airs raked aft.

Sail Settings for Mainsail SN-8

Outhaul

Upwind - tight in all conditions, except light airs with chop when it can be eased 25mm.

Offwind - the outhaul can be eased approx 30mm.

Cunningham

Only to be used when overpowered. Particularly useful when overpowered on a 3 sail reach. (Do not pull on in light air to remove creases running from the luff).

Kicking Strap

No tension needed until mainsheet has to be eased to prevent heeling. Slack in kicker must be taken up to prevent boom skying when tacking. As wind increases, so should kicker tension to maintain correct leech tensions. When very breezy, use as much as possible.

Top Batten

Light winds - little tension and fasten velcro.

Medium, heavy airs - as tight as possible.

Sail Settings for Jib 

Ideally you are looking for a slot shape between mainsail and jib that is parallel all the way from head to clew. This can be achieved by a combination of sheet tension and sheeting angle.

Luff Tension

Luff tension on jib should only be enough to remove creases coming off the luff.

Spinnaker

For the best from your North spinnaker, careful attention should be paid to the pole height. As a general rule, you are looking for the luff of the spinnaker to be folding at 1/2 height when trimming. You should also fly the spinnaker with both clews level. If you obey these two simple rules, you will find trimming easy and an extremely rewarding performance on all angles offwind.

Hull

The hull should be kept very clean either using T-cut or a low grade wet and dry.

Slot gaskets should be in excellent condition and all external screw heads, eg: self bailer, should be filled and faired.

470 Sails