Second part of an article from Bill Gladstone of North U on the US Sailing site.
A proper turn is just the first part of a tack. Part II – The Acceleration will complete the tack. As noted before, all the losses from tacking accrue during this critical second phase. Typically, (on keelboats) losses are between one and two boat lengths. Our goal is to minimize losses. Coming out of the tack directly to a close hauled course with full trim will leave us with a long slow acceleration and result in losses of two boat lengths or more. Coming out too low, on a close reach, will provide quicker acceleration but at a low angle. The losses from slow speed are reduced here, but losses from poor initial angle take their toll.
The challenge is to strike the best balance to achieve quick acceleration at the most effective angle. The correct angle varies with conditions, with a wider angle required in lighter winds and bigger seas.
The trimmers can help. The jib should be trimmed a few inches short of full trim. As the boat accelerates, the jib trimmer trims in the last few inches, reaching full trim as the boat reaches full speed. If you have a knot meter then the jib trimmer should note the speed before tacking and count down to the driver as the boat accelerates out of the tack: “We’re 2.5 knots slow… Speed building… 2 knots slow… 1.7… 1.5… 1 knot below full speed… Half a knot… Trimming up to full trim… 2… Coming to full trim… At full speed.”
Meanwhile, the main should be eased so that the driver can steer the boat down to fully load the jib without fighting the main. If the main is over trimmed, the driver will have to fight weather helm to push the boat down to the jib, which is slow. Ideally, the main sheet will be eased, traveler pulled up to center the boom, and backstay eased to add depth and power to the main. As the boat accelerates, the main trimmer should trim to create weather helm to help bring the boat up to the ultimate close hauled course without the driver having to use the helm. As the boat reaches full speed, the main sheet, traveler and backstay will be at optimum speed and pointing settings for the prevailing conditions.
The driver should steer the boat to have the jib telltales streaming and the jib fully loaded. It usually pays-off to sail low enough to get the outside jib telltales active (but not stalled). In the vernacular, you want to “press the jib” while accelerating, whereas once you are at full speed you can sail a bit higher and perhaps allow the very luff of the jib to unload.
As the boat resumes optimum close hauled speed and pointing, the tack is complete.
If you are on the layline, now (at full speed) is the time for forward crew to start spinnaker preparations. If time allows, it is much preferred to hike out (or sit still) until the tack is complete and the boat is at full speed before starting spinnaker prep.
If you are not on the layline, then it is time to prep for the next tack. It will be here, sooner or later. Best to be… “Ready About?”