For 50 years, Danish company Gori Propeller has been one of the foremost names in folding marine propellers used on sailboat auxiliary motor drives. These propellers fold into a streamlined form when under sail, then open up like springtime blossoms the instant the motor drive kicks on. Gori's latest innovation, the Hybrid Propeller, is designed for electrified sail drives, giving captains the ability to lock the prop blades open when under sail to activate regeneration for the onboard batteries.
The new Gori Hybrid is a further development of Gori's 3-Blade Propeller, a little wonder that not only opens and closes to negotiate between forward motor propulsion and fast, slick, low-drag sailing but also features a mechanism that flips the blades over 180 degrees so their leading edges are on the opposite side. This gives the propeller the same pitch in forward and reverse. Gori won a DAME marine design award back in 1994 for this innovation. This video illustrates how the classic Gori 3-Blade folder works:
Now that electric propulsion has been gaining in popularity for the types of auxiliary sailboat drives on which Gori propellers are used, Gori has noticed demand for a regeneration function – a prop that can spin as it's pulled through the water to develop electrical current via the motor-generator. The company realized that with a little tweaking, its folding blade platform could be a natural solution.
"Using the Gori 3-Blade Propeller for regeneration is not new," said Lars Østergaard, Gori's senior VP of sales. "Customers have been using our original propeller for several years now, but it’s not optimized for this purpose."
Traditionally, Gori's propeller folds and unfolds directly in response to drive torque. When motor torque is applied, the propeller unfolds and powers the boat. When motor torque is cut off, the propeller folds to cut drag for more efficient sailing.
With the Hybrid, Gori has added a new locking mechanism that allows sailors to keep the propeller open when the motor is not driving. In this way, the new propeller stays open and spins from the forward momentum of the boat to generate power. The boat captain can, of course, unlock the blades to allow them to fold when hydrodynamic optimization and speed are prioritized over regeneration.
The Hybrid propeller offers a simple improvement on an already innovative design, and it immediately equips sailors with another tool for managing onboard power, a tool that can be used on its own or in conjunction with other sustainable generation technologies like solar panels.
"Extensive testing has been conducted both here in Haderslev, Denmark and with a manufacturer of electric propulsion," Østergaard said in introducing the Hybrid prototype at the 2024 Metstrade show last November. "We are delighted with the results, and it’s time for us to tell the world that effective regeneration with a folding propeller is possible."
Gori plans to begin deliveries of the production Hybrid propeller this year. It will be available for both sail and shaft drives with diameters ranging between 18 and 30 inches. It has not published pricing information, and price will ultimately depend on the specific drive to which it's fitted. As a rough reference, though, we see Gori's current lineup of traditional 3-Blade folding propellers retailing anywhere from US$4,000 for the smaller variants to over $12,000 for the largest ones.
Gori also plans to work with electric and hybrid drive manufacturers to make the propellers available as part of new propulsion systems.
Source: Gori Propeller
