Some sails are cut to fit the mid girth of >65% but a code 0 with such measurement will not sail well upwind since it becomes too round. To count as a downwind sail and to fit the Swiss Rating System, the mid girth should be above 65% (ORC 55 - 75%). To get a MH0 into any kind of rating system is difficult, if not impossible, since the mid girth is significantly less than 65%. It can make sense depending on the area where you sail. If you want three different sails is one's own decision. With a normal asymetrical geannaker (A2), a so called 'runner', you would not change before 100° wind angle and stay with the code 0 - but again - all depends on the strenght of the wind. With the FR0, you would change a bit later, probably between 70 and 80° - if at all. If you use a reacher (A5), means a flat and small asymetrical gennaker as I use it on Serafina with a surface of 50m2, you can change - depending on the wind force - from 60 to 70° apparent wind angle from the MH0 to the A5. For this reason, often Nylon is used as a material for the code 0 but I think this does not come up to the expectations of the more experienced sailor but fits perfectly well the needs of a cruising sailor. However, most of the sails are some kind of compromise since most of the cruising boats hardly pass their hull speed limits. Nowadays, the so called code 0's are widly used on cruising boats since the handling and the manoeuvres are easy, especially hoisting and retrieving is much easier than with a normal gennaker/spinnaker. Picture: approx 120° apparend wind angle with the FR0 Upwind, the difference to the former flying genoas is not huge but both sails present a wider range of use, especially on reaching and also downwind courses. We use radial cuts similar as they were used in the past for the flying genoas. The classical Code 0 (FR0) on Saphire is 35m2 whereas the MH0 is 45m2, means almost 30% more surface. Nylon cloth streches too much and is not suitable for tight upwind legs. Picture: FR0 on Saphire with a surface of 35m2 For Saphire we use laminates instead of Nylon for both, the MH0 and the FR0. As such, the FR0 is between a reacher (A5) and the MH0 but on a small boat you probably dont use both sails. On the other hand, the FR0 can be used in a bit stronger winds especially downwind. With a bigger overlap the sail can be closed better and the deepest profile lies at around 45%, what gives a good up-wind-profile. This is due to the fact that the 30° angled spreaders are very long and if the sail is shorter, it cannot be closed in the same manner. The profile of the MH0 is somewhat flatter. Picture: MH0 in a roughly 50 - 60° apparent wind angle, slightly open, creates an enormous propulsionĬompared to a 'fractional code 0' which does not go to the top of the mast (FR0), the MH0 can sail tigher upwind angles thanks to the huge overlap. In strong winds, the MH0 can even substitute the asymetrical gennaker, whereas, however, the risk of broaching increases, since pressure is always leewards. As such, the apparent wind increases and you get the impression to always sail on a reaching course even though you are already going downwind. However, it is important to accelarate in a tighter angle and to bear off slowly like on a catamaran to create the needed apparent wind for propulsion. Thanks to the big surface it is possible to use the MH0 up to apparent wind angles of 120°, especially in stronger winds.

Picture: huge overlapp of >200%, attached in the first third of the bowsprit close to the hull to achieve a higher forestay tension. And of course in all kind of light wind areas especially upwind.

This sail presents an incredible potential especially if you sail in coastal areas on long courses or on bigger lakes like lake Geneva or Constance, where you have large crossings. The handling remains realitvely easy since the Code 0 uses a flying furler and can be rolled in easily. The boat quickly passes the theoretical hull speed limit and can cope with much bigger sized boats. However, a big advantage is reached in angles from 40 to 60° apparent wind angle since the huge overlap of the Code 0 starts working really well. Picture: mainsail boom winwards over the centreline to open the jet between the sails It is very important, however, to have the mainsail boom significantly windwards over the centerline to open the jet between the sails and to use a lot of twist to depower the mainsail at the same time. With increasing wind strenghts however, the advantage gradually shrinks and once you reach 6kts of true wind, you need to change to the normal 15m2 jib, otherwise the boat is overpowered and no real advantage results on tight upwind courses. In true winds between 1.5 and 2 kts, the boat speed reached double wind speed. On tight upwind legs an apparent wind angle of 30° could be reached with very good speed. On my Serafina I used a 45m2 big MH0 over the last season and reached very high speed limits.

Gennaker vs code zero