Thank you, it is very helpful to understand the evolution of the sail plans and the reasons all these sails were developed. I am not trying to steal the thread but it could be helpful to all of us if someone could give a historical perspective on sail plans. The way I understand it is:
Boats from the eighties had a mast head rig, multiple jibs/genoa's and relatively small mains. They would typically use spinnakers for downwind sailing. The 155% genoa was/is a versatile sail for those rigs. Then people realized one sail weight is not enough for all wind speeds/angles, so they moved the rig forward, making it a fractional rig with smaller jibs. The jib became an upwind sail only and most of the drive was coming from the main. Spinnakers went out of favor because they are too much work. Instead of having one heavy genoa, now you have a small jib for upwind work and an asymmetric for broad reaching. Then people realized that if you have a flatter stern and sufficient power you develop more speed and better VMG downwind when broad reaching, so now you have a number of asymmetric/code 0 whatever sails that maximize the broad reaching speed. Is this approximately correct?
The question then is, if I have an eighties boat (Hunter 31) and my downwind performance is lacking, what is best for me? Get a spinnaker and learn how to manage it single handed or get an asymmetric and gybe downwind? Not only in terms of speed but also in terms of handling, cost to install (i.e. polling out the genoa is easy, while having a spinnaker pole is a lot of cost and effort, rigging, etc.). An asymmetric would be an easy addition (just a hallyard, possibly a sprit) but will it give me good VMG downwind given that my stern was probably not designed for an asymmetric? Ideally, I would like to compare polars of similar boats to my Hunter 31 for polled out 155% genoa, asymmetric and symmetric?
Thank you,
SV Pizzazz
To fully understand this you have to look at sailplan performance, and yachting rules over time. They drive yacht racing design, and therefore yachting 'fashion', and cruising yacht design.
Back in the 50s starting with the CCA rating then the IOR and even continuing to PHRF, racers and designers were faced with a rule that rated sail (AKA boat horsepower) area as .5(J*I)+.5(P*E), NO MATTER HOW BIG YOUR GENOA**. So what did this do? You got boats with tiny mains on short masts, and huge overlapping (up to 180%) genoas. It was 'free' horsepower. This flew in the face of what designers knew would actually give best real-world performance (high aspect rig) but the rules won out. Race boats got designed like this, and cruisers followed along. For decades.
Once IOR gave way to the non type-forming IMS rule, tall non-overlapping rigs started to take over. Everywhere except for USA-serving builders, where racing under PHRF (which allowed up to 155% without penalty) continued to rule. Interim boats from around 2000, like the First 36.7 and the J/109 raced with genoas here in the US, but with jibs in Europe. But make no mistake, a overlapping raceboat has not been designed in 20 years. This has finally been helped along in the USA where finally most PHRF boards now give credit for smaller than 155% headsails.
Cruisers soon learned the advantages of non-overlapping rigs. The smaller single jib could be used in 90% of wind conditions. And the bigger main still just dropped into lazy jacks. But the weak spot is off-the-wind. On BlueJ as soon as we crack off we're looking for a kite. The current joke is 'race boats used to carry 4 headsails. Now they carry 1, but 4 spinnakers'. And that's true for us!
But what about the cruisers? Spins and codes will help, but it's work/trouble/hassle/etc. Well, thank the French. Their crazy desire for short handed/solo racing created a similar need, an easy-to-deploy spinnaker system. That's where endless line furlers were invented, and the tech trickled down to cruisers.
Now it's not uncommon to see non-overlapping cruising boats with a furler kite set on the bow, ready to deploy as soon as the wind moves far enough aft. And when cruising, if the wind is not quite far enough aft, turn down! ;^)
** ever wonder where the term 'rated sail area' comes from?? Now you know.