Steering an IMOCA Open 60 in fair winds
The IMOCA Open 60 is a yacht which is designed with sailing with favourable winds in mind. Choosing the right sail combination can save the crew work and headaches. Most of all because with this type of sailing, the autopilot is shorter on reliability.
Down to its design and the speeds it reaches, the IMOCA Open 60 is a boat which creates an apparent wind making it almost never beneficial for the yacht to sail on a dead run. Also, with 20 or 30 knots the boat performs lengthy planes on the waves which can make for an unstable course. That's why over the last few days we've heard that many of the skippers are spending hours at the helm, as in these conditions the autopilot can't be completely relied on.
The impossibility of delegating a large share of the work to the third crew member means that a functional sail combination is vital; one which can be quickly adapted, with minimum effort according to wind shifts in direction and force. The key is to choose the foresail carefully and to adapt the total sail area according to the breeze by reefing up or down. The mainsail is the most used in these situations. The wind picks up and it's reefed, then if it picks up even more, another reef. If it drops, the reef is taken off.
So the possibilities at the bow are many. We can start by looking at the asymmetrics, which are typical for quartering winds. The A2 and A3 use topmast halyards and are suitable for winds of less than 25 knots. The A2 for more open courses (some 135º) and the A3 for closer angles (100º). For breeze over 25 knots the A6 and A5 are usually used, in both cases, since they are accompanied by big winds and they use a 7/8 halyard, they usually require the mainsail to be reefed with at least one reef. The A6 is used in more open winds (135º) and the A5 for closer angles (100º).
For beam reaching there are also many different possibilities. In general, if the winds are light, and lighter than 12 knots, the Code Zero (tight reaching topmast sail, hauled into the boom) is ideal. If the breeze is between 12 and 20 knots then the mainsail is usually used with a solent, hoisted to 7/8 of the mast. If winds of 20 to 30 knots are blowing, then a reacher (tougher than a solent, but uses the same halyard) usually accompanied by some reefs is used.
As mentioned earlier, the usual dilemma in this puzzle is when and how to switch the configuration. When the wind force changes, reefing up or removing a reef from the mainsail is less tiring and dangerous than changing a foresail, so the decision is often made based on these factors. When there is a distinct wind shift it is also easier to change course than to change the foresail. Of course, tactics and the boat's progress are factors of great importance, so a balance must be struck.