After launching at Berkeley Marina recently, I watched a 25' C-Dory launch and prepare to go to sea. NOTE: It's remarkable to me how much more room I have in the Rosborough (which is 25' plus the hull extension and outboards)! Anyway, the skipper of the other boat rushed around and got his icebox in the cockpit, perched his Bimini-style top (over the cockpit), and generally got her ready. He then parked his rig (small, compared to mine; must be pretty nice to tow) and ran back to his boat. He started up the single Yamaha 115 outboard and let it warm up, then put her in gear.
There was a tone difference to the engine (the product of the transmission engaging), but no frothing of wake at the stern as I was expecting. I was more than a little interested now, as I had never seen an outboard behave this way. I thought briefly that it was a jet, but even a jet produces disturbed water. The skipper gave the engine a quick burst of power, and then walked back and looked at it, evidently as bewildered as I and several others in the area had become.
He went back to the helm, turned off the engine and raised it out of the water. Because of my position about 40' behind him, I got a first look at the prop shaft. He had no propeller, and at first I thought that he'd spun one off. But, in thinking about it, there had never been prop wash, even for a moment.
I could tell by his face that he was just as surprised to see a bare shaft as I was. In talking to him later, after he'd pulled the boat out of the water again, I learned that he'd just put a new propeller on the boat (after hitting the original one on a rock in an Oregon river this summer) and had spent $600 total to do that. He remembers thinking that "Someone could just steal this!" and then letting the thought go. And someone had. Probably at his home in Redding, California, on the curb where he leaves his boat all day and night, and likely during the day when he was at work. He figures the thief would have taken about 3 minutes to dislodge his cotter pin, nut and thrust washer and remove the propeller ... and all he'd need was a multi-tool or a pair of needle nose pliers.
I've never had problems with the aluminum prop on my lake boat, and it and Kokomo live at home (which is, these days, well off the beaten path on our own acreage) near Paradise, CA. But I got to thinking that the two props on my boat were pretty valuable (stainless steel, etc.) and would make a thief a quick $1000+ if they were stolen. Aside from the expense of replacing the props, there was the reality of traveling somewhere to use the boat (usually at least a 4 hour proposition) and finding, upon arrival, that your carefully-pampered outboards don't have what they need to 'go' (though I can't imagine leaving for such a trip without checking the props). NOTE: This fella had traveled 2 hours further than I had (6 hours) to get to Berkeley Marina, and had no idea where to go to find a propeller and the mounting kit for his boat. I directed him to the West Marine store in Alameda, but he was going to look for somewhere closer.
I decided to take affirmative action, and did research on the propeller locks that are out there. I settled on McGard propeller locks, ordered them, and had them on Kokomo the following week. In doing my research, I learned that, in California, one of every 24 stainless propellers is stolen! This includes the props on lots of boats that are not trailerable (it's evidently easy to remove them in the water too, and the thief - who does his work underwater - is less prone to being caught). Alarming. The McGard locks mount in about 10 minutes (once I had the original prop nut, cotter pin and the thrust washer removed) and are designed to simply spin if someone without the "key" tries to remove them. I'm impressed with the quality of these locks, and only a little concerned about operating the engines without cotter pins on the propeller shafts (the McGard system requires torquing to their specifications and relies on other than the cotter pin method to secure the prop). I liked the product well enough that I also purchased one for the prop on my Volvo SX outdrive on the ski boat.