View Full Version : Prop versus rudder
06-13-2010, 01:29 PM
I was motoring along taking the boat back to the ramp when the motor started to free rev? I kill the motor, jump over and feel the prop, yes the prop, touching the rudder. So being that I was in sight of the boat ramp I sat on the bow and paddled to the ramp, apparantly I have the eyes of an eagle for as long as I was paddling. So I pull the boat to the trailer and we winch slash back the trailer under the boat and then pull it out of the water. I noticed the prop was bent/cracked immediatley and went ahead and brought it home.
Woke up this morning did some tinketing an here is what I found
06-13-2010, 01:37 PM
Were you in reverse when it happened?
I'm betting the shaft slid out of the coupling (behind the transmission) because the setscrews came loose. Good think the prop hit the rudder, otherwise the shaft and prop tend to depart the scene, leaving you with a 1" hole in the bottom of your boat where the shaft used to be.
06-13-2010, 01:38 PM
When I inspected the coupler it looked free of gouges, the set screws are still in place and the key was laying in the coupler loose. The end of the prop shaft is also free of gouges and looks "unharmed."
When my friend bought the boat several years ago he had the prop shaft break. A buddy of mine, who works in an industrial machine shop, built him another prop shaft. It seems to have held until now.
At least the boat ran great all day! meaning my wife and kids really enjoyed it. My first carb rebuild seems to have been sucessful and the IgnitorII e/i conversion, and IgnitorII coil ran great all day!
06-13-2010, 01:42 PM
Were you in reverse when it happened?
Actually, I was running about 4400 rpm when the boat got a good little wave. It caused the steering wheel to jerk in my hand, the rudder stoping the prop from leaving the scene of the crime
06-14-2010, 02:32 PM
When I inspected the tail of the trans, the coupler and the prop shaft it appears to have just slid out. The coupler was broached the full length axially and the shaft is broached the same. The only thing holding the shaft in place was the set screws and key; my rudder too.
I talked with a freind ( machinist ) and he suggested putting everything back together rotating 90* from the key way and drilling/tapping two set screws thru the coupler and dimpling the shaft for the ends of the new set screws.
I am also thinking about shortening the key and welding up a little (1/4")
of the key way in the prop shaft near the tranny. My thinking is this will help the shaft also
06-16-2010, 07:55 PM
I sent the prop to OJ props today, hopefully it can be repaired... atleast Clarksville isn't to far from their shop so the shipping was cheap
I messed with the coupler and the set screws are stripped out, any tips for removal of stripped set screws?? There is another hole for a set screw about 120* from the key way, I need to re tap it so I can have a better hold on the prop shaft like my buddy suggested.
The shaft went back on the coupler with the set screws and key in place. It took a few taps of a block of wood on the prop shaft to reset things to how they were before the shaft slid out.
Is this a problelm with older boats and a single taper prop shaft? Thanks Art
06-20-2010, 11:18 AM
I got the prop back from Eric, in 3 days! Had work, so this is the first time I am able to use the home computer and camera to load some pics.
I used some of my free time at work to drill out the set screws, You learn to really miss the machine shop and its tools at your disposal when you have to use a cordless Dewalt and some cheapy harbor freight drill bits.
The coupler already had some other holes drilled and tapped 120* of the key way, they were not being used and need to be tapped to remove the rust. Also there is a 1/4" or so hole drilled straight through the coupler, was this for a role pin? This is what I was thinking of doing to the coupler anyway, I don't think I will drill the shaft for the roll pin. After a discusssion with my father (Mechanical Engineer with his PE license) says he wouldn't put a roll pin in it the set screw should be enough.