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Cruising on 2 engines

Printed From: BMPT Forum
Category: Boats (In alphabetical order)
Forum Name: Brave Class
Forum Description: Discussion about Brave Class boats
URL: http://www.bmpt.co.uk/forum_posts.asp?TID=595
Printed Date: 26 March 2026 at 5:16pm


Topic: Cruising on 2 engines
Posted By: jonathan napier
Subject: Cruising on 2 engines
Date Posted: 17 January 2009 at 12:53pm
Hi
I wonder if anyone out there who operated the Braves for the RN could confirm that they would often run with the middle engine shutdown for economy. My father flew the photo helicopter in some of the Cowes Torquay races and later in the bar when he asked the RN chaps what would happen if one of the race boats started to pull away they answered that they would ring down to start the third engine!!
A lovely story, I wonder if it's true?
Thanks
Jonathan Napier
 


Replies:
Posted By: johnk
Date Posted: 18 January 2009 at 12:37am
Hi Jonathan,
 
Welcome to the forum, great to hear about this particualar classe of post war coastal forces, I know nothing about this but sure others may well.
 
JohnK

Posted By: cducane
Date Posted: 18 January 2009 at 10:40am
Hello Jonathan. I was only a teenager when the Brave Class were under construction but I do remenber being aboard while they were doing their trials. My father was the designer of the class. Tim Parr who is well known to the BMPT was working at Vosper at the time and having now discussed your question with him, I come back with the following. It was certainly possible to operate the boats on the two outer of their Proteus for some economy at a slower speed. As a matter of fact, should you wish to operate the centre turbine on its own you could achieve an even slower speed. You will find a comprehensive paper that the old man wrote on their design and construction on the BMPT website, which you might find interesting.      

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crusade

Posted By: jonathan napier
Date Posted: 18 January 2009 at 3:48pm
Many thanks for the answers, much appreciated. I have read the Brave document Charles and what a fascinating read it is. I'd certainly hope to hear some operational information about things like speed attainable and fuel burn on either 1 or 2. The proteus is a 'Free' turbine with no connection between the compressor and turbine which would enable operation on less than 3 without damage/overload to the engines. If you tried to do the same with a diesel you would just overload and overheat the engine.
Fantastic website, absolutely packed with indispensable info.
cheers Jonathan

Posted By: johnk
Date Posted: 18 January 2009 at 11:11pm
Hi all,
 
Great to see Charles and Tim able to advise you, know Tim well heritage lottery fund moniter for the Medway Queen, and of course for Ark Royal and Medusa!, just finished a day on the Rhine River Patrol vessel Velo 2, new garboard strakes going and, myself sanding down the hull! not a British Military powerboat I know, but still interesting I hope.
 
JohnK

Posted By: cducane
Date Posted: 19 January 2009 at 9:45am
As far as I can ascertain the, max speed on trials was 53 knots. These, however, were undertaken at all times on all three engines. I do not know whether this was at "Full Load" or at "Action Load". The difference being with a full war load in both conditions and half fuel load for the latter. I cannot help with the fuel burn figures but there might well be someone out there scanning the website who does know!!

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crusade

Posted By: Magic Fingers
Date Posted: 19 January 2009 at 9:36pm
A whole 3 knots faster than MTB102 achieved in1937, wow!
 
Richard.


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If it ain't broke don't fix it!

Posted By: johnk
Date Posted: 20 January 2009 at 8:17am
Hi  there,
 
Indeed,  20 odd years for 3 knots!
 
Johnk


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