CS30 prop size? Vibration - SailNet Community
LinkBack Thread Tools
post #1 of 1 Old 08-21-2012 Thread Starter
Oaksail's Avatar
Join Date: Jan 2011
Location: Oakville, Ontario
Posts: 58
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 7
CS30 prop size? Vibration

I'm wondering if anybody knows the original supplied prop size for a CS30. (1989 Canadian Sailcraft 30)
I have done a considerable amount of searching and reading on appropriate prop sizes for a 30' boat.
I currently have a 2 bladed LH 15d x 15p x 1 and from what i read this seems to be far larger than normal.
I have a Volvo 2002, 18 hp with a 2.4:1 ratio.
In neutral i can get the motor to 3400 rpm and it is surprisingly quiet and vibration free.
In gear in flat water she will go 7.0 - 7.2 gps knots but the motor only gets to 2700 rpm. I cruise at 2200 rpm getting 6.4 knts (which is hull speed). There is a lot more noise and vibration than i would like.

I've only starting looking a prop size because last winter i replaced a traditional stuffing box with a PSS shaft seal and i have had a rattle in the drivetrain ever since.
I use Mainesail's excellent tutorials for just about every thing i change on the boat. The only thing i didn't follow of his was to change the coupling. The old one was an easy slide back on. Prop shaft to my eye looked good.
Alignment? i replaced the cutlass bearing at the same time but the old one looked in fine shape. I assumed alignment was good if it didnt wear out the old cutlass bearing.
I'm going to get some feeler guages this weekend and check.

Rattle is most prevelant at low rpms, gone at cruising speed.
Rattle was not there with old stuffing box, noise and vibration are about the same at cruising speed.

Is it possible for a too large of prop to setup a vibration that would cause an old coupling to shake and rattle on the shaft.

Fresh water boat, no barnacles. I've put on fins, snorkel and mask and gone underneath. I cannot feel any slop in the rudder, cutlass bearing or zinc (magnesium for us). No damage to prop.

I have my boat almost back to showroom condition and i know this rattle and vibration was not an option.

1989 CS30
Oaksail is online now  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Prop Cavidation: Vibration-Caused? SEMIJim Gear & Maintenance 4 05-05-2012 07:45 AM
Prop Size Wyatt6969 General Discussion (sailing related) 3 04-08-2010 05:19 PM
Prop/Prop-Shaft Key Size? Skipaway Gear & Maintenance 7 07-29-2008 09:04 PM
harmonics vs vibration prop issue rdunncpa Gear & Maintenance 2 06-18-2008 03:46 PM
Prop size? mwrohde Gear & Maintenance 7 05-29-2007 05:52 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome