Sail in Forward, Reverse, or Neutral? - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 01-25-2010
Junior Member
 
Join Date: Feb 2009
Location: Issaquah, WA
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
elcap373 is on a distinguished road
Sail in Forward, Reverse, or Neutral?

I have a Hurth ZF 10M transmission on the 24 hp Universal diesel in my Newport 33. The ZF 10M manual indicates the transmission should be in forward or reverse when sailing – not in neutral. I would think it would be advantageous to sail with the prop in neutral to let it free-wheel and reduce drag. Is it truly necessary to operate under sail in with the transmission in forward or reverse?
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 01-25-2010
jrd22's Avatar
Courtney the Dancer
 
Join Date: Nov 2000
Location: San Juan Islands., WA, USA
Posts: 3,843
Thanks: 3
Thanked 16 Times in 16 Posts
Rep Power: 15
jrd22 will become famous soon enough
The prop shaft free wheeling turns the output shaft of the transmission but in most transmissions that does not provide lubrication or cooling which can do a lot of damage.
We put ours in reverse to prevent it from spinning (Volvo).
__________________
John
SV Laurie Anne

1988 Brewer 40 Pilothouse

Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 01-25-2010
Member
 
Join Date: Dec 2007
Posts: 49
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
rocinante33 is on a distinguished road
In neutral, the trans may not lubricate as it should. Since the input shaft is not turning (only the output shaft) the oil in the trans may not circulate to the bearings.

Also, the freewheeling prop is not really less drag than a prop which is stopped. I know it is counterintuitive, but the spinning, freewheeling prop is more drag.
__________________
Keith
Rocinante
1983 Ericson 33
Channel Islands, California
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 01-25-2010
tager's Avatar
Senior Member
 
Join Date: Nov 2008
Posts: 991
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
tager is on a distinguished road
Counterintuitive.

That is counter to my intuition, can you explain why the spinning prop presents more drag?
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 01-25-2010
Zanshin's Avatar
Senior Member
 
Join Date: Aug 2006
Location: Germany
Posts: 2,206
Thanks: 0
Thanked 15 Times in 15 Posts
Rep Power: 9
Zanshin is on a distinguished road
tager - coming from flying this was also counterintuitive for me. This topic is a popular one and there have been a number of studies done that come to different conclusions. The one that I found to be rigourous in method was in a study done at the University of Strathclyde and can be found in pdf form at http://strathprints.strath.ac.uk/567...ints005670.pdf
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 01-25-2010
pvanv1's Avatar
Hinterhoeller HR28
 
Join Date: Nov 2007
Location: Hamburg and Wilson NY
Posts: 156
Thanks: 9
Thanked 0 Times in 0 Posts
Rep Power: 8
pvanv1 is on a distinguished road
The Hurth will not be damaged by sailing in Neutral. One of the few transmissions where that is the case.
__________________
Paul Van Voorhees
Certified Tohatsu TLDI Technician
Mgr, Obersheimer Sails
Buffalo, NY USA
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 01-25-2010
Member
 
Join Date: Apr 2008
Posts: 70
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 7
newpbs is on a distinguished road
Be Careful

I'm not sure which Hurth I have but the manual specifically states that the transmission should be in reverse when sailing.

Paul
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 01-25-2010
nickmerc's Avatar
Senior Member
 
Join Date: Nov 2008
Location: O'Fallon, MO
Posts: 563
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 7
nickmerc is on a distinguished road
It is correct that a spinning propeller creates more drag than a stationary one. I too fly airplanes and it is very well demonstrated when your engine quites. You will glide significantly further in a fixed pitch propeller airplane if the prop is stopped.

Also, weather the bearings receive lubrication or not, there is no need to turn the shaft when not producing power. It will still wear the bearings needlessly.
________
How To Roll Blunts

Last edited by nickmerc; 08-18-2011 at 06:54 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 01-25-2010
Senior Member
 
Join Date: Jul 2001
Posts: 1,174
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 14
k1vsk will become famous soon enough
I'm not sure boat props follow the same theory as those on airplanes. Being a compressible fluid, the analogy to that of airplane props (in air) falls apart and if you were to substitute the dynamic properties of water vs. air in the equations of the Styrathclyde example, the coefficient of drag changes inversely.

Regardless, this issue has been debated and argued for decades and so-called experts constantly disprove each other. Seems to me you should either get a folding/feathering prop if drag is of great concern or risk the transmission by not following the mfg recommendations. Your choice.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 01-25-2010
MSN2Travelers's Avatar
Badger Sailor
 
Join Date: Sep 2006
Location: Milwaukee
Posts: 176
Thanks: 1
Thanked 4 Times in 4 Posts
Rep Power: 9
MSN2Travelers is on a distinguished road
I crew on a Pearson Flyer and the manual for the boat indicates the transmission should be in reverse too.
__________________
Paul
`99 Beneteau Oceanis 352, #282 WiTCHCRAFT
Milwaukee, WI
Sailing Lake Michigan and the Great Lakes
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

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:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

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

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sloop, Cutter or Ketch jsgsail Boat Review and Purchase Forum 17 12-26-2008 03:47 PM
Traveler usage? Humpwalker Seamanship & Navigation 22 02-17-2007 11:54 AM
The Basics of Reefing Mark Matthews Cruising Articles 0 03-29-2004 08:00 PM
diffrent rigs? (schooner, ketch, cutter, sloop) jbarros Boat Review and Purchase Forum 2 07-09-2003 05:10 PM
First Sail of the Season Bruce Caldwell Learning to Sail Articles 0 06-05-2003 09:00 PM


All times are GMT -4. The time now is 11:19 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.