How to Sail a Gunboat 68 Upwind: Mastering Apparent Wind
Leaving Port-Camargue on a Gunboat 68, crossing the Gulf of Lion under a fresh offshore breeze — flat water for most of the transit, and plenty of wind to work with. A good day to talk through what actually happens to apparent wind as boat speed builds, and why that governs how high a performance multihull can point.
A full range of conditions in one passage
The day ran through the full spectrum: third reef and J3 in the strongest breeze, gusting past 32 knots down to 18, water rough enough early on to send spray clean over the bow — down to one reef and J2 later as the wind eased, sailing flat and fast at close to true wind speed once conditions settled. That range in a single day is normal for offshore delivery work, and it’s exactly the kind of conditions where understanding apparent wind properly stops being theoretical and starts mattering to how the boat’s actually sailed.
Why the true wind angle drops as the boat speeds up
Sailing upwind at 15 knots of breeze, 9 knots of boat speed, apparent wind angle sitting around 20 degrees — comparing that to a slower moment earlier in the same conditions shows something worth understanding properly: the apparent wind angle barely changed between the two moments, but the true wind angle shifted from around 44–45 degrees out to 53. That’s not the boat sailing lower or losing ground sideways. It’s a direct result of speed — the faster the boat moves, the more it drags the apparent wind forward, and that relationship holds regardless of what the true wind angle actually is.
What actually limits how high a multihull can point
The real limiting factor isn’t the wind angle at all — it’s the jib car position. Trimmed all the way to its maximum inward setting, there’s nowhere further to bring the sheet lead in. Once the jib car has run out of travel, that becomes the ceiling on how close to the wind the boat can sail, full stop. Push the boat faster from there, and one of two things has to happen: either the sheeting angle needs to come in further, which isn’t possible once the car’s maxed out, or the true wind angle has to ease off to compensate. In practice, on this passage, that meant dropping the true wind angle slightly rather than fighting for pointing that the sheeting geometry simply couldn’t deliver.
That’s the piece that trips people up about sailing a fast multihull upwind: pointing ability isn’t purely a function of wind angle or sail trim skill — it’s capped by the physical geometry of where the jib car can actually travel to, and going faster changes the apparent wind enough that the same gear setup that worked at one speed becomes the limiting factor at a higher one.
For more discussion on apparent wind boats see Apparent Wind vs. True Wind: The Biggest Misconception in Sailing