Sailing with currents: limiting drift by working on conduction

Sailing with currents, even when cruising, is one of the most difficult “skills” when we are on a boat, which is why there are specific tricks on adjustments and handling to deal with this situation. In some cases, as is the case in some areas in northern Europe, for example, or even in the Strait of Messina, it may be almost or completely impossible to sail upstream at certain times of the day.

We will not cover these extreme cases, but those where sailing with the current is still feasible. Depending on the direction of the current, the difficulty coefficient increases, so let’s see what are the tricks, especially upwind in medium-light wind, to limit the effects of the current and the drift that results in some situations.

Navigating with power – when logs and gps tell us so

There is an easy way to calculate current strength by comparing Log and Gps velocities. Recall that the latter is the one that governs the advance on the earth’s crust and is not affected by the current, as is the case with the Log number that directs the velocity on the water. If GPS speed and LOG are equal it means we are not in the presence of current or if there is this is lateral and only affects the drift. If the LOG speed is greater than the GPS speed, it means we have contrary current. For example, if the log speed is 7.5 knots, and the GPS speed is 7, we will have 0.5 knots of current against. Conversely, the current will be in favor.

This figure tells us the possible favorable or unfavorable intensity, but not its exact direction and origin. The current at the jaw for example affects the log, but it is not exactly on the bow. It will be up to our observation then to keep an eye on the possible drift as well as the Log and Gps numbers.

Navigating with the current – How to have effective appendages

The most important thing when sailing with power is to always have efficient appendages. What does it mean? Sailboat appendages gradually begin to lose efficiency at low speeds. The slower the boat slows, the less the drift develops its anti drift action, the less accurate the rudder will be. When we sail, to cite a practical example, upwind starboard tack, with a sustained current coming from upwind to the jaw, if we are too hemmed in we will have a sluggish boat that will increase its drift, accentuated by the current, due to inefficient appendages.

If we want to limit the “damage” that the current does to us, it will be necessary to bring the boat, especially if the breeze is light, with a slightly less narrow upwind angle and therefore faster, it will benefit the appendages and decrease the drift.

Sailing with currents, how to refine the adjustment

We will try to keep the rudder “loaded” at all times, giving power to the mainsail with the trolley so that the boat has a gyre tendency that can counteract the current and at the same time give bite to the rudder to keep it effective. We will then sail with the backstay soft, consistent with wind strength, and the mainsail carriage upwind of the centerline, with the sheet a little more open than necessary, to seek maximum power on the sail.

At the same time, we will keep the mainsail and jib halyards slightly softer than we would normally do in a given wind strength, unless that wind strength is 18 knots and up and thus requires us to do a certain type of running. By combining a course to the wind just a little wider and powerful sails we will already have some weapons to use against the current and side drift.

Sailing with currents, watch out for trajectories

There are methods, and a formula, for calculating the drift, but what we are interested in here is rather to understand how we can adapt our boat’s conduction and course to the current. Upwind, with medium-light breeze, and current from the right jaw, this will have an important impact: if we need to reach a target against the wind it will be necessary to “adjust” the trajectories to absorb the drift.

Our ideal course will be a few degrees upwind of the goal to be reached, implying that if the half to be reached is, for example, at 1 o’clock relative to us, the right layline will have to be calculated wider. We will make a longer left tack than we should, so that after the turn we will have a higher approach course than the goal to be reached and limit the risk of having to make more turns. In case the current subsides, we can widen the upwind angle slightly and gain a few tenths of speed.

Mauro Giuffrè