Thats why I always get a kick out of that ad where the guy says to his wife
"honey, I finally got to the end of the internet...". ws
Printable View
Thats why I always get a kick out of that ad where the guy says to his wife
"honey, I finally got to the end of the internet...". ws
On cars, at least the smaller nut goes on last. The big nut would torque the prop so it can't slip, the smaller nut is a jam nut to keep the big nut from backing off. I can't say for a fact that is true on a boat, but it makes good sense.
Great quote from a great man... there are damn few of us left.
This topic has been discussed adnausium and if my memory serves me correctly there are a few exceptionally smart fellow's on this forum that explained the physics behind the large nut needing to be closest to the propeller. All I know is that it seem to make the most sence to me to have something of larger mass and greater "bite" or more threads or what ever you tech guys want to call it pushing against the propeller and use the smaller nut as a locking nut.
Besides, this is the way Hatteras delivers their boats. I'll bet you a beer that an engineer or two has figured it out there.
I think this one of those debates that will never end. Obviously, both methods seem to work, or we would hear more stories of props flying off. I would have normally agreed that the big nut goes first until the physics it was explained to me. It now makes more sense to me that the last nut put on carries the load and therefore should be the one with the most threaded area.
I have tried both big nut first and small nut first and never had a prop fall off. Last year I had a diver do a prop swap and I noticed on the next haul out the nut on one prop didn't touch the prop. I guess you really don't need a nut. Just don't back up first. Good Luck
I don"t mean to keep raining on everyones parade about the "right way" to do things but I have logged thousands of hours on scores of different boats and I can assure you there is a RIGHT way of doing things and a wrong way. (maybe it has yet to catch up to you but IT WILL!!) Example is a buddy of mine asked me to come along on a trip from Marsh back to F Laud and I was more than happy to oblige. The boat had been in Marsh for about 4 months and he decided to have the bottom cleaned and a diver insisted that a prop was out of wack and it should be recon before the trip back. So being the responsible owner he agreed had it "trued" and we flew in Thurs evening leaving Fri morn for some "fun" in Lucaya. Great trip leaving Marsh past "Hole" onto Lucaya. The next day head out 30 miles for some yellow fin action I notice a bad vibration after trolling a weedline for dinner, back down to get rid of some trash we must have picked up and BANG. Hmmmm must have a rope or flotsam on the prop? Nope prop is GONE! After further inspection prop nut in incorrectly installed on the other shaft as well!! This is a 2005 boat with under 500 hours. Had this prop "let go" 24 hours earlier we would have been around Hole In The Wall nearly 50 miles from any safe harbor and probaly sinking from throwing a prop at 30 knots (nearly 35 MPH for layman) So....it does matter
Oh that's nice.
And about what I expect when its done wrong.
I am curious as to what would be accomplished by installing the large nut against the prop hub. The rationale that I learned that makes perfect sense to me is you install the small nut first, tighten this up pretty good to be sure the prop and key are seated correctly, then put the large nut on and give it your best torque. This results in the small nut being fully unloaded on its threads and the larger nut carrying the torque load. Also, should the large nut creep back a hair, the unloaded small nut will continue to providing locking friction as it can move to the stern some. And with the cotter pin in place, the prop will be there when you haul out. Am I missing something?
Pete