Thread Tools Display Modes
Old 09-30-2012, 08:41 AM   #1
Senior Member
City: Maine
Country: USA
Join Date: Feb 2011
Posts: 109
Vocabulary Clarification

The hunt is now officially on, and my wife and I are looking to buy a trawler. When I look at the specifications of a boat I am interested it, I see the words 'direct drive', which are then followed up by the gear ratio of the transmission. What does direct drive mean? I work on commercial ships, and when we say direct drive, I know that the shaft is directly connected to the flywheel or thrust bearing, and that a transmission does not exist. Is there another definition of direct drive or is this a mis-speak? There are others too, but I think that maybe the person writing the descriptions is just using the wrong words in some cases, but maybe the words are different from what I am use to in other cases. Any clarification would be appreciated.

Anthonyd is offline   Reply With Quote
Old 09-30-2012, 11:17 AM   #2
djmarchand's Avatar
City: Essex, Ct
Country: USA
Vessel Name: Bella
Vessel Model: Mainship Pilot 34
Join Date: Aug 2012
Posts: 1,987
Direct drive in recreational boating terms means an engine with a bolted on transmission driving a prop shaft more or less in line with the engine.

Other types of drives are v-drives, jet drives and I/O drives.


djmarchand is online now   Reply With Quote
Old 09-30-2012, 11:22 AM   #3
Scraping Paint
City: -
Country: -
Join Date: Oct 2007
Posts: 13,748
Some people use the term direct drive to differentiate from V-drive. Direct drive in this case means the props haft extends straight back from the engine to the prop. V- drive is just that--- the engine is mounted "backwards" and a short shaft connects it to the V-drive transmission. V-drive engines are most often mounted near the stern of the boat under access hatches in the cockpit. The elimination of the midships engine room provides more user volume in the interior of the boat.
Marin is offline   Reply With Quote
Old 09-30-2012, 11:48 AM   #4
ben2go's Avatar
City: Upstate,SC
Country: USA
Vessel Name: The Caroliner
Vessel Model: Plans to build 30' Spira Sitka
Join Date: May 2012
Posts: 1,005
Stern drive,inboard outboard,I/O are the same thing just different terms.I agree with those above me.Direct drive in that case means standard inboard install with transmission and prop shaft extending aft through the hull to the prop.

ben2go is offline   Reply With Quote
Old 09-30-2012, 01:02 PM   #5
Senior Member
City: Maine
Country: USA
Join Date: Feb 2011
Posts: 109
Thanks for all of the replies. I know it must seem a little remedial to some of you, and I appreciate you all taking the time. Not having been around smaller boats is just another reminder that even though I work in the marine industry, there is some much I need to learn.
Anthonyd is offline   Reply With Quote

Thread Tools
Display Modes

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

All times are GMT -5. The time now is 11:43 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012