Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-02-2016, 17:39   #1
Registered User

Join Date: Dec 2014
Posts: 589
Cat prop size and pitch

Can someone tell me what the prop size and pitch would be for a 38-40ft. catamaran running approx. 30 hp diesels. I understand there are variables but would appreciate a ball-park idea or what you are running. Gracias.
__________________

__________________
captlloyd is offline   Reply With Quote
Old 11-02-2016, 18:34   #2
Registered User

Join Date: Feb 2015
Location: On board in the Chesapeake
Boat: Chris White Voyager 48
Posts: 410
Re: Cat prop size and pitch

You're right, there are a lot of variables, weight and hull shape among them. If you have a specific model in mind, you'll get a better answer.
__________________

__________________
Joe & Sue
S/V Presto
jdazey is offline   Reply With Quote
Old 11-02-2016, 18:43   #3
Registered User

Join Date: Dec 2014
Posts: 589
Re: Cat prop size and pitch

Quote:
Originally Posted by jdazey View Post
You're right, there are a lot of variables, weight and hull shape among them. If you have a specific model in mind, you'll get a better answer.
OK, how about 38FT Lagoon? Thanks for your reply.
__________________
captlloyd is offline   Reply With Quote
Old 11-02-2016, 21:17   #4
Senior Cruiser
 
44'cruisingcat's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 7,453
Images: 69
Re: Cat prop size and pitch

There's bound to be someone with a 38 ft Lagoon who can help you. Maybe ask the question in the Lagoon forum?
__________________
"You CANNOT be serious!"


John McEnroe
44'cruisingcat is offline   Reply With Quote
Old 12-02-2016, 09:05   #5
Senior Cruiser
 
akprb's Avatar

Cruisers Forum Supporter

Join Date: Jan 2015
Location: Alaska
Boat: Hunter Legend 40.5
Posts: 511
Re: Cat prop size and pitch

Yes a lot of variables. Ours was severely over pitched when purchased (1800RPM max). We had a 3 blade max prop that allowed adjusting the pitch (not a straight forward task but doable).

We found Yanmar's specs for max rpm for our 3J series engines (27hp each) then adjusted pitch accordingly until we reached it. Actually did this over three seasons. First year we took 4 degrees out then two degrees each subsequent haul out until happy.

Pretty sure there are faster ways to get closer but we were a bit lazy on this one and got the job done eventually.

Catamaran Storm Tactics | sailingohana
__________________
akprb is offline   Reply With Quote
Old 12-02-2016, 09:39   #6
Registered User
 
duefocena's Avatar

Join Date: Aug 2010
Location: Newport Beach, CA.
Boat: TPI Lagoon Catamaran 42'
Posts: 234
Images: 1
Re: Cat prop size and pitch

Quote:
Originally Posted by captlloyd View Post
Can someone tell me what the prop size and pitch would be for a 38-40ft. catamaran running approx. 30 hp diesels. I understand there are variables but would appreciate a ball-park idea or what you are running. Gracias.
I have Autoprops on a 42' Lagoon and am very pleased. Replacing two blade props, these have the same thrust in fwd and rev. Really handy when backing down on a following breeze or current. Never had them "hang up" like other feathering props I've owned. Loaded in no current @ 1,800 revs I move at 7kts-8kts.
Ab Marine has a good website and they are knowledgable to Lagoon props.
ABmarine.com
From their web site:
"The Autoprop is an automatically self-pitching feathering propeller that maintains maximum efficiency at all times. It has a higher efficiency over a wider range of RPM settings, producing higher speeds with lower engine RPMs."
__________________
duefocena is offline   Reply With Quote
Old 12-02-2016, 13:58   #7
Registered User

Join Date: Aug 2015
Location: AUSTRALIA
Boat: Schionning Wilderness 1340
Posts: 35
Re: Cat prop size and pitch

You really should make a decision re folding or feathering props.

I prefer feathering as you get 100% astern propulsion though many owners of folding props seem happy with astern performance but folding props should be 3 bladed.

From my research the Autoprop isnt recommended if your boat will sail above 14knots.

Won't be a problem with a Lagoon
__________________
Aqualibrium is offline   Reply With Quote
Old 12-02-2016, 14:51   #8
Marine Service Provider

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Marmaris
Boat: FP Orana 2010, Lipari 2011, Hélia 2013, Catana C 47 2013
Posts: 1,030
Re: Cat prop size and pitch

For L 380 and 30 HP, 17X12 or 13 (folding 3 blades) would do the job.


Cheers


Yeloya
__________________
yeloya is offline   Reply With Quote
Old 12-02-2016, 16:54   #9
Registered User

Join Date: Dec 2012
Location: australia
Boat: Mashford Claris
Posts: 32
Images: 1
Re: Cat prop size and pitch

send kiwi props an email or fill out calculator form on their website I like the fact they are composite and you can buy spare blades , not possible with some other brands
__________________
takeabow40 is offline   Reply With Quote
Old 13-02-2016, 04:13   #10
Sponsoring Vendor
 
EWOL Props's Avatar

Community Sponsor

Join Date: Nov 2015
Posts: 82
Re: Cat prop size and pitch

Hi captlloyd, you can run your own calculation at this link: http://www.ewoltech.it/index.php?rou...ory&path=65_66

If it doesn't work directly, just copy and paste on your browser.

Enjoy !


Quote:
Originally Posted by captlloyd View Post
Can someone tell me what the prop size and pitch would be for a 38-40ft. catamaran running approx. 30 hp diesels. I understand there are variables but would appreciate a ball-park idea or what you are running. Gracias.
EWOL Props is offline   Reply With Quote
Old 13-02-2016, 16:53   #11
Senior Cruiser
 
atoll's Avatar

Cruisers Forum Supporter

Join Date: Mar 2010
Location: gettin naughty on the beach in cornwall
Boat: 63 custom alloy sloop,macwester26,prout snowgoose 37 elite catamaran!
Posts: 9,311
Images: 75
Re: Cat prop size and pitch

prout elite 37 ft ,single engine use
for 32 hp 14x14 with 2.6:1 gear box
or 14x10-11 with 2:1gear box
or 13x8 with 1.6:1 box
__________________
my catamaran building project updates http://www.cruisersforum.com/forums/...36#post2502136
atoll is offline   Reply With Quote
Old 13-02-2016, 17:46   #12
Registered User

Join Date: Dec 2014
Posts: 589
Re: Cat prop size and pitch

Thanks for all the great replies.
__________________
captlloyd is offline   Reply With Quote
Old 14-02-2016, 18:57   #13
Registered User

Join Date: Apr 2013
Location: Sailing in the Caribbean
Boat: Outremer, Outremer 55 Std, 16.1m
Posts: 7
Send a message via Skype™ to Fast Cat
Re: Cat prop size and pitch

What work well is setting pitch so at RPM of about 2700-2800 the point at which the fuel to power stops going up so steep on the fuel to RPM graph .
This give good power to fuel consumption and engine will still go up in Rpm but takes a while and gets to about 3000 Rpm.
Has worked well for me ,I have had a Privelege 49', Catana 471 and now an Outremer 55.
Just a sugestion
__________________

__________________
Fast Cat is offline   Reply With Quote
Reply

Tags
pitch, size

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
420: Propeller size and pitch Fearnow Lagoon Catamarans 0 10-03-2015 13:39
Prop size and pitch Eddietwostacks Forum Tech Support & Site Help 4 18-01-2015 19:03
Prop Pitch on Dinghy By Invitation Propellers & Drive Systems 6 10-08-2012 05:10
Propeller Size and Pitch for Yanmar Saildrive CatamaranDan Multihull Sailboats 6 09-07-2012 08:15
Prop Size and Pitch? ciclon1942 Propellers & Drive Systems 17 26-05-2009 06:50



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:37.


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.