Cruisers Forum

Join CruisersForum Today

  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
Thread Tools Search this Thread Rate Thread Display Modes
Old 10-04-2012, 18:51   #1
Registered User
stupidape's Avatar

Join Date: Oct 2008
Location: Charleston, SC
Boat: in the market for a cat
Posts: 6
Prop sizing for DE upgrade

So first allow me to apologize for being another novice fascinated by the promise of electric sailing. I understand it is more expensive. I understand it is heavier. I understand that it is untested. I also understand it is far more gentle and much quieter. Also, it's pretty much the future and that is where I am going to spend the rest of my life, so I am interested...

I am looking at a pretty big faster cat, specifically an Outremer 49 or a Dolphin 46 (if I can find one). I am not a naval architect, nor an electrical or diesel technician. There are so many ways to skin the cat on the Diesel-Electric question, but I am leaning toward a high VDC (144) solution. I am hoping to do something like one 9 KW motor for each hull, backed by a couple of compact 9 KW DC generators with around an hour of overall battery reserve.

So my question is, for a layman, how would you figure out if the size is right to allow you to do a comfortable 7 knts? And, how do you select the prop for this job?

I have read that due to their torque at low RPM, larger props are indicted with electric motors. How do you decide what size and pitch is right for a 12-14 tn cat? How do you adjust the "calculators" that are abundant on the intertubes for the greater torque capabilities of the EP?

I understand that this is complex and there are a host of variables to be addressed. Which variables matter most? What formulas do I plug them into?

I am looking for an 85% number that I can use for budgeting purposes to try to decide if I can take this on, without my wife leaving me for a more sane person. I thank you in advance and look forward to the lively debates that DE always brings into the conversation.

Your friend,
stupidape is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 04:47.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.