Shamrock V racing cutter rig (white) contrasts with the ketch rig fitted for ocean passages (shaded); a snug and seamanlike sail plan compared to the racing mast, which was 151 feet above deck and needed four sets of fixed crosstrees (spreaders) and one set of swinging crosstrees to support the shrouds. The hollow spruce “topmast” was removed as far as the second crosstree position for ocean sailing. The boomless trysail, with two rows of reef points was sheeted by powerful tacklesto the quarter quarter.

Shamrock V was the first British large-class racer to hoist and lower her mainsail on a reel winch, fitted below deck. However, this innovation paled before the numerous winches on the American Enterprise. These were worked by eight hands who remained at their stations below deck throughout the races, keeping the deck clearer, saving windage and lowering the yacht's center of gravity in racing trim.

Shamrock V did indeed meet bad weather on her transatlantic crossings. The outward voyage was typical, taking twenty-four days from Brixham in Devon to New London, Connecticut. Lipton's steam yacht Erin escorted her and towed whenever conditions permitted, which, to the crew's relief, was not often, as the racer was much easier under her double-reefed trysail and storm jib than when corkscrewing along through long steep Atlantic seas on a towline. Sometimes she lost touch with Erin for days and was becalmed in mid-ocean, with the crew working in vain to get her along with a big headsail and squaresail. They boxed about for a time before the western horizon darkened again with shricking squalls, and days of big seas and wind forced them to crawl about the heaving deck at the change of watch, or to tend the badly chafing running rigging. The foc'le became almost uninhabitable in the pounding seas and some hands shifted their berths to the sail locker in the long flat counter, where the slamming was as noisy as in the long overhanging bow but it was drier. Often, the saloon skylight would darken with a green sea and cascades of water would pour down over the watch at their meals below. On deck, they clustered around the wheel, in streaming oilskins and soggy sea boots, swaying to the pitch and roll of the lean racer. This was the other side of the America's Cup races.