Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 19-05-2013, 13:03   #1
Registered User

Join Date: Jul 2012
Location: Morro Bay, CA
Boat: 45' Horstman TriStar
Posts: 2
I have the opportunity to purchase a much needed new prop for $100. The pitch, diameter and bore are all the same but it's a lefthand prop and my boat is set up for a right hand prop. Can I just switch my forward and reverse cables and essentially run in reverse or would there be other mechanical concerns I'm not aware of? My motor is a 27 HP Isuzu Pisces on a sailboat. I'm not sure of the type of transmission.
__________________

__________________
Triple Helix is offline   Reply With Quote
Old 19-05-2013, 13:05   #2
Registered User

Join Date: Jul 2012
Location: Morro Bay, CA
Boat: 45' Horstman TriStar
Posts: 2
My other option would be to stay RH with a 20" diameter prop with the same pitch up from the original 16". The costs for both options are about the same as I've found good a used one.
__________________

__________________
Triple Helix is offline   Reply With Quote
Old 19-05-2013, 15:23   #3
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Switching RH Prop For LH prop

It will all depend on your transmission - it makes little difference to the engine. You will need the same gear ratio and assurances that the thrust bearings, lubrication, etc are OK for prolonged reverse operation.

If you have a saildrive, most of them are OK running either way.

As for increasing the diameter 4" and keeping the pitch - unless you have the clearance and were significantly underpropped with the old prop, you will probably have trouble with that one.

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 19-05-2013, 15:23   #4
Senior Cruiser
 
S/V Antares's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: Annapolis, Bahamas
Boat: 1983 Gulfstar 36
Posts: 1,249
Images: 1
Re: Switching RH Prop For LH prop

You likely have a mechanical gearbox (ZF, TMC, Newage, PRM) and you cannot change RH to LH. This is because in reverse the main and layshaft are connected by a spur gear that is very small and cannot handle the continious duty. If run this way for long it will fail.

What gear box do you have?

There are prop calculators online. Just plung in the HP , Waterline, Max RPM etc and get the proper info before wasting your money.

Most small diesels rotate Counter clockwise or left hand (Looking at the flywheel end). The gearbox input is LH but the gear reduction changes this to RH.
__________________
Will & Muffin
Lucy the dog

"Yes, well.. perhaps some more wine" (Julia Child)
S/V Antares is offline   Reply With Quote
Old 19-05-2013, 16:31   #5
Guy
Registered User

Join Date: Feb 2013
Location: So. Oregon, USA
Boat: Seafarer36c
Posts: 4,308
Re: Switching RH Prop For LH prop

The Paragon trans in our boat was burned up back in the day running from VA to the Bahamas in reverse because of bad info, so I would be careful. There are good deals on props all over. Even if you could run it backwards, you would be wearing in new wear patterns on the gears and probably shorten it's life.
__________________
Guy 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




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:25.


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.