Ron Boyte and the San Geronimo Windmill


Ron Installing the vanes


Ron Boyte &
The San Geronimo Windmill Story

by Malina Hills 

  “Curiosity”, that’s what drove Ron Boyte to propose restoring the dilapidated windmill on the newly acquired CLC conservation easement at San Geronimo Creek - part of the Estero Bluffs open space.  Little did Ron know that his 2003 proposal would consume his time and his and wife Kathy’s garage for two years.  Ron’s passion for learning while tinkering and a mindset that “windmills are cool” helped him persevere as he converted the rusted and broken disaster into a historically accurate and beautiful windmill.


 San Geronimo Windmill in 2003, and then in 2005

The San Geronimo Creek windmill is a 1930 Aermotor model and was used to pump water from a 40 ft well by San Geronimo Creek into a concrete basin for cattle at the ranch’s holding station.  San Geronimo ranch was first a dairy operation, before transitioning to running beef cattle.  As Ron likes to say, “The West would never have been settled without the water from windmills.”  According to the Aermotor Company, the windmill was designed in the 1880s, achieving the highest efficiency of that time, and was widely purchased through WWII.   In a 15-20 mph wind, the windmill could pump as much as 1000 gallons per hour. Using wind power to pump water remains an economical approach for many ranches today according to the Farm Supply Co. in SLO.  You can drive north on Highway 1 from Cayucos to view operating Aermotor windmills at Villa Creek and beyond.  

How a Windmill Works
Drawing courtesy of Aeromotor Co. Verbal permission to use picture form Aeromotor website obtained from Nick Orman of Aeromotor on August 16, 2021

While the windmill itself contains hundreds of parts, the conceptual design is fairly simple.  The rotating blades turn a rotor attached to a hub assembly.  The hub drives a gear mechanism that generates a vertical motion, driving a pump (“sucker”) rod up and down.  At the end of the pump rod is a hollow pipe with a plunger that pulls water into the pipe and pushes it upward from the deep well with each upstroke.  A check valve at the bottom of the pipe prevents the water from exiting the cylinder during the next down stroke.  (For a more detailed description see the Aermotor website at As Ron found out during reconstruction, the design is very intricate and elegant, including a self lubricating mechanism: chains dip into the pool of oil at the base of the engine and carry the oil up to lubricate the bearings in the hub. 

The San Geronimo windmill sits on an approximately 40 ft tower, the wheel weighs 150 lbs and stretches 10 ft wide across the vanes, while the main motor assembly weighs about 330 lbs. In late 2003, Ron arranged for the Farm Supply Co. of San Luis Obispo to bring a crane to the creek to lift the motor off the tower.  Unfortunately, the motor case was stuck on the mast pipe, and the entire tower had to be lowered onto its side, and the mast pipe disconnected from the pump rod.  Then the upper portion of the windmill was loaded onto Ron’s truck bed and wrestled it into his garage for repairs.

Rusted hub and gear mechanism on the mast pipe.

 Repairing old equipment is never easy.  According to Ron, the motor was “stuffed full of the nesting material of an animal” and many of the parts were rusted or otherwise stuck in place.  After much “scraping and WD 40” Ron was able to remove most of the internal parts which generally appeared to be in good condition.  The motor case, however, remained firmly stuck on the mast pipe.  Two months of soaking, heating, twisting and banging eventually allowed him to separate them.  After fixing or procuring replacement parts, Ron mounted the motor assembly 11 ft off the ground and started to rebuild the wheel with its 5ft vanes.  As he was tightening a bolt to hold one of the spokes, the hub cracked!  He had to disassemble the hub and wheel, and with a little help from Rocky Poletti of The Farm Supply was able to procure a new hub and machine the shaft/hub into a tight slip fit.  

Repaired hub and gear assembly

  Unfortunately, while Ron worked in his garage, someone stole half of the tower on the ranch.  So he next rebuilt the tower!  


Rocky Poletti of The Farm Supply Co. lowers the windmill motor and wheel onto the tower.

In 2005, almost two years later it was time to erect the windmill.  Ron removed the moulding from his garage so he could get the rebuilt motor and wheel out door.  On a foggy day, the tower was erected and the rebuilt windmill assembly lowered onto the stand pipe.  Mission accomplished!  

Kathy and Ron Boyte celebrate Ron's achievement.

 The entire Cayucos community joined the CLC on May 1, 2005 for a spring time celebration of the Estero Bluffs open space and the dedication of the San Geronimo windmill.  Ron received a plaque and an inscribed windmill blade for his outstanding achievement.  Over 50 people joined the celebration, it was in Ron’s words “Superior”!  The CLC-led effort to procure the open space, Ron’s efforts to rebuild the windmill and the big celebration encapsulate what Ron and Kathy Boyte appreciate most about Cayucos, the sense of community that drives people to contribute and help each other out.

San Geronimo Windmill on the Estero Bluffs State Park - Danna Joy Images