By Sean Semmens, Dart Sails
Impalas are very difficult to beat on IRC handicap in 10-20 knots of wind. They hold their own downwind and are very fast upwind and especially good at pointing.
Your Genoa needs to be flat and the rig set up correctly to point high. The Genoa should be sheeted in hard against the shrouds again with little halyard. Unless overpowered the backstay should be off, outhaul tight, traveller around the middle of the track, the mainsheet pulled in until the top tell-tale starts to stall (flip to leeward) and the slack taken out of the vang.
Use your No 1 Genoa unless completely over pressed but easy for a sail maker to say as the sail will not last very long used in this manner but it will be fast By now your Impala will fly upwind.
Fetching you should ease the outhaul and sheet the Genoa onto the outside track. If over pressed fetching with the No 1 Genoa or large waves and over pressed up wind, change to the No 2 Genoa.
Opinions are divided about No.2 Genoas. They have a very narrow wind range. I believe a No.2 Genoa is the sail to use at around 17 knots to about 21 knots. The pointing angle is not quite as good, but compared to a No.1 you get less leeway so the outcome is very similar. The big gain with a No.2 is that the boat accelerates far quicker out of the tacks so around a race course it is usually faster. The No.2 is also surprisingly fast on a close reach, it sets very well opening the slot when sheeted on the outside track so is an excellent fetching sail. It is also far easier to steer to in waves than struggling over pressed with a No.1. The problem with the No.1 is that pointing is easy but bearing away to get speed is not easy so bearing away slightly to steer up the wave face or to duck a boat requires easing of sails but the No.2 is far more forgiving.
Other crews do not bother with a No.2 at all and change straight to No.3. This works well sailing in flat water and if you have a fairly heavy crew hiking on the side-deck. The No.3 is an efficient pointing machine and when in the grove is very efficient upwind. In this mode try changing down to the No.3 from the No.1 at around 20knots.
Hiking hard on the rail is an absolute must. Think of a kids see-saw in the park, sit right on the end 2 kids have a greater effect than Mum or Dad sat near the middle. The Impala is not very beamy and the distance from the toerail to the centreline is not great. If the crew sit with their knees on the rail instead of the absolute back side then the centre of effort of their weight is roughly 1/3 of the way off the rail. In other words 1/3 back along the see saw, losing 1/3 of the boats righting moment loosing essential sail holding capability. The sad fact is once about 12kts of wind the crew must hike and it must hurt, nothing else is good enough! The success full crews will have no mainsheet trimmer (done by the helmsman) and the headsail is let off and pulled in by the same person in the tacks to maximise weight on the rail.
Downwind you can sail almost straight downwind with the pole squared well back and set the pole higher than you expect, this will open the leeches, maximising the projected area.
Again crew weight forward is fast, but more aft when reaching to increase control on the helm.