yes...we saw a sequence of them tacking from onboard about 6 months ago (that video is long gone though). Spithill starts the turn and gets the boat just barely on the new tack...while a crewmember crawls back to the rear beam where he leans back in a prone position. When Spithill is ready, the crewmember holds the wheel steady while Spithill steps up onto the rear beam and walks at a face pace over to the opposite helming station. Once he has the new wheel, the crewmember releases and shuffles back to the net near the center. The boat is really pretty steady through it all - but there is nothing to hang onto while spithill walks over.

We have seen them making tight maneuvering drills where he just stays on the leeward side and drives from there if it's going to be a short run. If they do get into some manuevers on the start line you can expect to see him drive from the low side.