Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-06-2009, 11:03   #1
Registered User

Join Date: Oct 2007
Location: Beaumont
Boat: Passport 41-Touche'
Posts: 135
Prop Shaft Size?

I just had a passport 41 surveyed. They found the 1 1/2 inch shaft was turned down to 1 inch just before passing into the coupling. The engine is a 62 hp yanmar 4jh2-te. Questions 1. Will this shaft hold up without shearing? 2. not sure if there is room to cut off the 1 inch end of the shaft, then place a new coupler, maybe flexible coupler and still mount prop. 3. anyone know if rudder needs to be dropped to replace the shaft?
__________________

__________________
Eddie is offline   Reply With Quote
Old 14-06-2009, 05:31   #2
Registered User
 
James S's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: Yemen & Lebanon... the sailboat is in Lebenon, the dhow is in Yemen
Boat: 1978 CT48 & 65ft Cargo Dhow
Posts: 5,816
Images: 139
I think there are several things that help determine the shaft size....if its unsupported for some distance a thicker shaft would help eliminate "whip" in its length.

With just the info you have supplied, and with no personal knowledge of the Passport 41 I would think the end being turned down to 1" would be OK.

Originally my 48ft boat had a 72 hp engine with a 23" three bladed prop and an 1-1/4" shaft....this lasted for 30 years and about 30,000 miles.

What did the surveyor have to say about it?
__________________

__________________
James
S/V Arctic Lady
I love my boat, I can't afford not to!
James S is offline   Reply With Quote
Old 18-06-2009, 23:23   #3
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
That's a new one for me.

I would be very suspicious of that.

Loosing 1/3 of the shaft size?

Sounds like somebody was too cheap to buy the right coupling.
__________________
Chief Engineer is offline   Reply With Quote
Old 18-06-2009, 23:45   #4
Wayfaring Mariner
 
captain58sailin's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Homer, AK is my home port
Boat: Skookum 53'
Posts: 4,045
Images: 5
They should have turned the coupler and enlarged the hole instead, usually there is plenty of metal in the shaft hole on the coupler.
__________________
" Wisdom; is your reward for surviving your mistakes"
captain58sailin is offline   Reply With Quote
Old 19-06-2009, 03:38   #5
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,592
Images: 240
Quote:
Originally Posted by Chief Engineer View Post
That's a new one for me.

I would be very suspicious of that.

Loosing 1/3 of the shaft size?

Sounds like somebody was too cheap to buy the right coupling.
As the Chief Engineer notes, the shaft has been reduced to 66% of it’s original diameter.
This results in a reduction of cross-sectional shaft area to 44% of the original area.
I “believe” that the result is about 44%* of the original shaft strength (tortional).

* Perhaps even less, due to stress concentration factors.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 19-06-2009, 07:36   #6
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
I love it when somebody does the math at 0538........
__________________
Chief Engineer is offline   Reply With Quote
Old 19-06-2009, 09:20   #7
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
I dont know the PP 41 undershape. I assume it is skeg hung rudder...? If it is, then the skeg is your issue .... removing the rudder wont help right?.....
__________________

__________________
Cheechako is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Horsepower vs Prop Shaft Size nhschneider Engines and Propulsion Systems 18 29-01-2017 08:22
correct shaft size (+) vacendak Propellers & Drive Systems 14 23-07-2008 03:59
Prop shaft seal JGI417 Propellers & Drive Systems 11 18-11-2006 00:38
Help! Prop shaft woes svwhisper Construction, Maintenance & Refit 14 17-11-2006 16:12
Prop shaft removal rleslie Construction, Maintenance & Refit 13 18-05-2005 20:27



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:28.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.