Sailing Umavideo
How Many Sails Does it Take To Replace a Diesel Engine? | Step 488
May 31, 2026 · 17 min · 121K views
Red white blue sail billows against mountain sky
What this video covers
Dan and Kika of the all-electric sailboat Uma are ordering a complete custom sail suite from Precision Sails to replace their old set, which no longer fits the boat's new mast, rig, and deck layout.▶ 6:58 Because Uma runs on batteries with no diesel engine, the sails serve a dual purpose: propulsion across the widest possible wind range and regenerative charging through the drivetrain, making light-wind performance the design priority rather than heavy-weather handling.▶ 1:13 The new inventory comprises six sails: a mainsail, a larger but lighter-weight genoa for light-wind upwind work, a code zero for light-wind beam reaching, a symmetrical spinnaker for downwind running, a Solent jib on a second inner forestay for 25–35-knot conditions, and a dedicated storm jib on a removable inner stay.▶ 10:45 A trysail — rigged on its own separate mast track and attached to the boom so all standard mainsheet controls apply — functions as a fourth reef and pairs with the storm jib to keep the boat balanced above 40 knots.▶ 12:58 Precision's EU distributor Martin traveled to Olbia to take measurements in person.▶ 8:21 The previous spinnaker, a hand-me-down from a J boat, was undersized and never filled correctly; the old rolled genoa lost shape when reefed heavily during a 30–45-knot Atlantic crossing.▶ 5:39 Designing sails around intended conditions rather than racing-class names simplified the specification process across two calls totaling nine hours.▶ 14:33
More from Sailing Uma
From Sailing Uma — see the channel’s boat, crew, and every analyzed video.