My dad tried a couple of different approaches to getting the ‘right’ prop and engine rpm for our 38’ sailboat. First was diameter and number of blades (our boat had a full keel, so there was a 8’ wide keel just a few inches ahead of the prop) so the prop blades were ‘blanked out’ by the keel quite a bit. I know that the boat originally had a two-blade prop, but that one spent too much time not doing anything while blanked. You gotta remember that a sailboat is a displacement hull, and ours was limited to about 9 kts. With the anemic 4-cyl Chrysler-Nissan diesel, we had to fine tune quite a bit. While one prop/rpm was good for calm seas, another was better in heavy seas - the prop could ‘stall out’ when hitting waves hard… The whole exercise was meant to be the most efficient for fuel economy reasons (open-ocean traveling around the globe with ports few and far between, as well as availability of fuel!) I know that the engine liked one particular RPM, and prop efficiency demanded another… That’s why a different reduction box was necessary. Then there was the issue of prop drag while under sail power with the engine off… Dad being the engineer by profession figured it all out. I know he tried at least four props in various sea conditions before settling on one.
I know some sail boats that always stay close to port are now just having a huge bank of batteries and an electric motor to turn a prop. When they are under sail power, the prop spinning in the current back drives the motor helps recharge the batteries.
Yeah, when under sail on the open ocean, Dad had a trolling motor rigged as a generator… Mainly to keep the batteries charged for his HAM rig. Solar chargers back then (almost 30 years ago) were not as efficient as they are today…
Wow, awesome story and great work. I really enjoyed the photos.
Cool deal on the trolling motor; he must have re-wired the the controller, taking out the back-bias diodes out of circuit so the current from the motor’s motor (???) would feed into the batteries.
For years, we had nothing but a 200W solar panel and controller for daily electricity at my Mom and Dad’s place up in Heber, AZ. Used propane and Coleman Fuel for most of the lights - and the Dometic fridge and the Gaffers and Sattler stove. The 3 “deep cycle” batteries in boxes on the front porch took juice from the solar panel and charger, and fed the water pump, the cellular “bag-phone”, Mom’s Cobra CB, a broadcast radio and an “RV” TV/VCR (13" screen, ran off 12VDC like the radio and cellphone). Even after we got “real” electricity up there, Mom kept the battery bank/solar panel, “just in case” the power died in a storm. If I went up there to run Field Day; I’d pull a couple-three batteries off my own rack (we get power outages in Yuma, too) and add them to Mom’s rack to keep the 2M and 6M SSB rigs and the 6M amp from ‘eating all the electrons’ and completely draining Mom’s batteries over the weekend.
Ahhh, good times. I miss 'em.
73 DE Jimmy, KC7BDP
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Dad’s call sign was KA8DYZ, even though he got his ‘extra’ rating which used to have a two letter suffix. High school history teacher was W8IO. Also had a neighbor that was W8BON. Keep up on your rating. We might need to notify the faithful. “The chair is against the wall. John has a long moustache”
I was over at a friend once and he asked “did I ever show you a picture of my first Jag?” He went to his desk and pulled out a black and white photo of I beleive a 1958 150, he said “here’s my first Jag, I had 13 trouble free miles with that car” The downside was those miles weren’t consecutive!
Must have been the Lucas eletrical system.