Vibration/ cavitation survey

[oak]

I have posted this on the Yahoo site also

As the issue of vibration and or cavitation seems to be restricted to the Pilot 34 with single diesel it would be interesting and helpful if pilot owners listed the following info for a comparison survey;


1 prop diameter and pitch
2 original or new prop
3 the year built
4 was the faring of the dead wood done
5 where is the boat located
6 any other pertinent information

1 “Miri” has a 25R38 L- cup tip by Hy Torq
2 the prop to my knowledge is original
3 the year built is 2007 hard top purchased in 2016
4 the dead wood was fared by the previous owner
5 the boat is located in Highland Beach SE Florida
The vibration/cavitation is intermittent some times none and some times pronounced

Hoping a survey will give us some insight into this issue

 

[DavidM]

I owned this single engine Pilot 34 from 2013 to 2018.


1. Can't remember, but had it scanned and trued a few years ago with no difference in cavitation.
2. Original OEM
3. 2003
4. Faired the dead wood a year after truing with no effect on cavitation
5. Located in NC, Ct and RI


There is a very definite decrease in cavitation with a squeeky clean hull. The cavitation with a normal bottom occurs at more than 3,000 rpm. Since I cruised at 2,800 rpm it was never a problem.


David

 

[oak]

I owned this single engine Pilot 34 from 2013 to 2018.


1. Can't remember, but had it scanned and trued a few years ago with no difference in cavitation.
2. Original OEM
3. 2003
4. Faired the dead wood a year after truing with no effect on cavitation
5. Located in NC, Ct and RI


There is a very definite decrease in cavitation with a squeeky clean hull. The cavitation with a normal bottom occurs at more than 3,000 rpm. Since I cruised at 2,800 rpm it was never a problem.


David

Thanks for your response to the survey

My issue seems also to be somewhat better with a very clean bottom. It was not noticeable for the first 8 months after I purchased the boat and during the initial sea trial. I have the bottom cleaned monthly by a diver. Some time helps sometimes not so much. The boat has not grounded or had any damage since I am the owner and was in excellent condition when I purchased. After hauling and launching with a fresh bottom she runs good, then after several months it returns. Seems so odd that a slightly fouled bottom is the entire cause.
I am trying to determine from the survey if the issue is prop diameter, pitch or the number of blades
Some have suggested that a 5 blade prop would run smoother.