We own a 473 with a Yanmar 100HP engine. Since buying this boat which came with a Maxi prop we have experienced cavitation vibration over 2000RPM. We have altered the pitch which does give us more speed ( 6knots at 2300) but I want to resolve the vibration issue. Anyone experienced similar? I am thinking of changing to a fixed prop if I can get one.
Beneteau 473 propellor issue
- Thread starter John Mott
- Start date
Some vibration seems to be commonplace on sailboats in general. Chances are you will never eliminate all of it. If the boat is a shaft drive and not a sail drive, I would suggest checking the shaft alignment, the condition of the motor mounts, the cutlass bearing, and propeller blades for balance or damage. If the prop is a 2 blade, changing to a three blade may help.
Soft, worn Yanmar mounts combined with cutlass bearing gave me vibrations. After changing the cutlass bearing the vibes were down. Haven't changed the mounts yet.
In my Beneteau 361 I used to have lots of vibrations. I changed the engine mounts, new cutlass bearing (old one was in a very bad condition), shaft alignment (after removing the shaft and ensuring was not bent) and replaced my 2-blade fixed prop with a 3-blade fixed propeller (the 2 blades always create vibrations behind the skeg).
Now, I have some vibrations at around 1100-1200 rpm but these are due to the 3-cylinder engine, nothing to do with the shaft/propeller (I mean these vibrations are there either in gear or not). So do make sure that the vibrations are because of the shaft/propeller before start changing things.
PS: Of course I expect an 100hp engine to be much smoother than mine.
Now, I have some vibrations at around 1100-1200 rpm but these are due to the 3-cylinder engine, nothing to do with the shaft/propeller (I mean these vibrations are there either in gear or not). So do make sure that the vibrations are because of the shaft/propeller before start changing things.
PS: Of course I expect an 100hp engine to be much smoother than mine.
As my repairman noted that in 2000's Beneteau the cutlass bearing cooling/water intake system is inadequate i.e. can be badly worn in five years depending on motoring hours. My vibes were easily reduced by changing the bearing, since I was pretty sure that the propeller wasn't to blame.
Thanks for the reply. The Max prop is three bladed. I guess that I am getting cavitation from the prop as it is worse when in rough seas. I have tried to alter the blade angle hitch although gave me more forward speed didn't resolve the vibration.
I had this issue a few years back when we struck a floating object and damaged the Max Prop. Sent it out to PYI and had it rebalanced and reconditioned. Perfect afterward. Recommend you do the same.
Thank you. That sounds like a Very good suggestion. Who is PYI by chance? I am based in Europe. Did you get the cavitation issue as well?
I know this is not an answer specifically but I question the shaft size. My 473 is a 2005 and the shaft size is approximately an inch and a eighth I am guessing yours is the same.
The shaft seems very small to me.
Cutlass bearing wear obviously will play a large part in vibration.
The shaft seems very small to me.
Cutlass bearing wear obviously will play a large part in vibration.
Your shaft diameter is 35mm, not, "Approximately an inch and an eighth." That information might come in handy some day, you know, if you were ever to replace a zinc or something.
Your shaft diameter is 35mm, not, "Approximately an inch and an eighth." That information might come in handy some day, you know, if you were ever to replace a zinc or something.
My shaft is actually 30mm and I know that because I have changed the zinc. and 30-35mm is "approximately" an inch and an eighth As an American I just find it easier to imagine an inch and an eighth vice 30mm
But hey you can be as technical as you like
D'oh!
Yeah, your somewhere-around forty foot boat has an approximately inch and an eighth diameter prop shaft. Let's be sure not to get "technical" and actually describe things accurately.
I think I'm going to have to put you on ignore and move on to more productive things.
That would be an accurate description of my thoughts.
I would be happy to discuss all things Beneteau with owners who operate with common sense and imagination.
I'm you will have the last word here....and you are welcome to it.
That would be an accurate description of my thoughts.
I would be happy to discuss all things Beneteau with owners who operate with common sense and imagination.
I'm you will have the last word here....and you are welcome to it.
D'oh!
Yeah, your somewhere-around forty foot boat has an approximately inch and an eighth diameter prop shaft. Let's be sure not to get "technical" and actually describe things accurately.