Technology and Operations  
This forum is for discussing technological & operational matters pertaining to U-boats. 
RE: U-Boat Propulsion
Posted by: Rainer Bruns ()
Date: July 21, 2000 02:31PM

Hi Robert,
I am not sure that I fully understand your question in view of your phrase 'on one side' and 'on the other side'. Let me try to explain it as follows:
First: Both propulsion systems (port and starboard) were set up identically. From forward to aft end machinery was set up in the following way:
Diesel engine==>Short Shaft==>Electric Motor==>Main Clutch==>Shaft with Main Thrust Bearing==>Shaft inside Stern Shaft Seal==>Shaft outside and screw support by strut bearing.In addition the shaft could be mechanically decoupled at the aft end of the Diesel.
Thus under normal operation the Diesel would be turning the E-motor (switched to and functioning as a generator charging batteries) and turning shaft and screw. Once batts are full, Diesel can be declutched, E-motors switched from generator charging mode to propulsion (drawing juice from batts) etc.
Since everything is duplicated on both P&S, you can see that the engineer could stop one Diesel, switch it's E-motor to pro=
pulsion (drawing juice from the other E-motor in generator mode), and do routine maintenance or emergency repairs on the Diesel with both screws turning. So you can see, there are a couple of options how to get on.
In addition you could stop one side completely and proceed with Diesel or electrically with the other. This happened on U175, when homebound off West Africa she got a pasting from aircraft DC causing an uncontrolled dive down to 310 meters and severe damage. Among other damage, the shaft strut and bearing just foreward of the screw broke off, leaving the tail end of the shaft assembly unsupported. They made it home to Lorient on one shaft using the other diesel for charging only.
You are correct that there is a sideways slewing under one shaft propulsion. This is easily corrected by applying a couple degrees of counter rudder. This has no ill effects on the rudder shaft ansd bearings as they are designed for full hardover turns
at max. speed. Obviously, it is a bitch to steer in any kind of sea; and maneuvering at close quarters you might as well call a tug.
Hope this was helpful, RB

Options: ReplyQuote

Subject Written By Posted
U-Boat Propulsion Robert Eno 07/21/2000 12:44PM
RE: U-Boat Propulsion Rainer Bruns 07/21/2000 02:31PM
RE: U-Boat Propulsion Rainer Bruns 07/21/2000 04:01PM
XXI propulsion system. SuperKraut 07/27/2000 09:58PM
RE: U-Boat Propulsion Robert Eno 07/21/2000 09:42PM
RE: U-Boat Propulsion Don Baker 07/23/2000 07:05PM
RE: U-Boat Propulsion Rainer Bruns 07/24/2000 01:40AM
RE: U-Boat Propulsion Don Baker 07/24/2000 11:54PM
RE: U-Boat Propulsion Rainer Bruns 07/25/2000 01:31AM
RE: U-Boat Propulsion Rainer Bruns 07/25/2000 01:46AM
RE: U-Boat Propulsion Don Baker 07/25/2000 05:43AM
RE: U-Boat Propulsion Rainer Bruns 07/25/2000 01:02PM
RE: U-Boat Propulsion Robert Eno 07/24/2000 12:31PM
RE: U-Boat Propulsion Garth 07/24/2000 06:57AM
RE: U-Boat Propulsion Andrew Hetherington 07/24/2000 08:16AM
RE: U-Boat Propulsion Rick Mann 07/25/2000 09:38PM
RE: U-Boat Propulsion Don Baker 07/27/2000 01:00AM
Re: U-Boat Propulsion Robert Laloie 07/27/2017 01:43PM
Re: U-Boat Propulsion Don Prince 05/14/2018 06:01AM

Your Name: 
Your Email: 
Spam prevention:
Please, enter the code that you see below in the input field. This is for blocking bots that try to post this form automatically.
       **  **     **  **      **  **     **  ******** 
       **   **   **   **  **  **  **     **     **    
       **    ** **    **  **  **  **     **     **    
       **     ***     **  **  **  *********     **    
 **    **    ** **    **  **  **  **     **     **    
 **    **   **   **   **  **  **  **     **     **    
  ******   **     **   ***  ***   **     **     **