Notices

3a versus no.6s

Thread Tools
 
Old 11-09-2016, 01:06 PM
  #1  
Registered
Thread Starter
 
Join Date: Sep 2016
Location: southampton uk
Posts: 7
Likes: 0
Received 0 Likes on 0 Posts
Default 3a versus no.6s

Hi
We have ssm3a drives(with uprated internals good for 800hp apparently). Changing engines to about 850-900hp. We'd like to stick with the 3a drives. The boat is used in very rough seas in the U.K.
No.6s have been suggested as necessary, what do you all think?
Thanks Jonathan
jonathan49 is offline  
Old 11-09-2016, 05:51 PM
  #2  
Registered
iTrader: (5)
 
Join Date: Mar 2008
Location: Traverse City MI
Posts: 3,592
Received 278 Likes on 97 Posts
Default

3A are good drives, so are all speedmasters IV, V, and VI. If your going to make a change the #6 is a great choice and will handle the power better, but they are heavier, expensive, and quite a bit of work to convert. It would be less expensive to buy a spare set of 3A drives and freshen both sets a couple times before redoing your transom and rigging to install a pair of sixes.
offshorexcursion is offline  
Old 11-10-2016, 12:50 PM
  #3  
Registered
Thread Starter
 
Join Date: Sep 2016
Location: southampton uk
Posts: 7
Likes: 0
Received 0 Likes on 0 Posts
Default

Many thanks for the reply.
Forgive the lack of knowledge but I had assumed they all used the same transom parts and so an easy job. So, in fact they are completely different and the whole transom will need re-doing, shape of hole etc etc. Is the no6 the big daddy with nothing above apart from Arnesons?
jonathan49 is offline  
Old 11-10-2016, 01:00 PM
  #4  
Platinum Member
Platinum Member
iTrader: (6)
 
F-2 Speedy's Avatar
 
Join Date: May 2012
Location: Midwest & T-Rock
Posts: 10,418
Received 3,051 Likes on 1,357 Posts
Default

You also have the M8, similar to the #6 but Mercury's newest big power drive
F-2 Speedy is offline  
Old 11-10-2016, 11:41 PM
  #5  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,556
Received 1,821 Likes on 907 Posts
Default

Originally Posted by jonathan49
Many thanks for the reply.
Forgive the lack of knowledge but I had assumed they all used the same transom parts and so an easy job. So, in fact they are completely different and the whole transom will need re-doing, shape of hole etc etc. Is the no6 the big daddy with nothing above apart from Arnesons?
Thread on conversion from SSM5's to 6's. BTW, SSM5's are a shortened 3A. http://www.offshoreonly.com/forums/c...comes-six.html
Griff is offline  
Old 11-11-2016, 01:53 AM
  #6  
Registered
Thread Starter
 
Join Date: Sep 2016
Location: southampton uk
Posts: 7
Likes: 0
Received 0 Likes on 0 Posts
Default

Many thanks Griff, great thread. Lot of work in that conversion!! I think for now we'll stick with the 3as and see how we get on, the main reason being cost(anyone got cheap no6s?)
All the best

Last edited by jonathan49; 11-11-2016 at 05:08 AM.
jonathan49 is offline  
Old 12-03-2016, 06:16 AM
  #7  
Registered
Thread Starter
 
Join Date: Sep 2016
Location: southampton uk
Posts: 7
Likes: 0
Received 0 Likes on 0 Posts
Default

One further question please..... what is the weak point of the 3a? Which part/shaft/bearing fails first?
Thanks Jonathan
jonathan49 is offline  
Old 12-03-2016, 06:58 AM
  #8  
Registered
iTrader: (1)
 
donzi matt's Avatar
 
Join Date: Jul 2003
Location: Moultonborough NH
Posts: 1,339
Received 7 Likes on 5 Posts
Default

If you are boating in very rough seas like you say a wise investment would probably be a set of Drive Guardians to help prolong the life of those 3A's.
donzi matt is offline  
Old 12-03-2016, 04:14 PM
  #9  
Registered
iTrader: (1)
 
Join Date: Jun 2009
Location: Chicago
Posts: 8,736
Received 4,322 Likes on 1,241 Posts
Default

^^^ agree.
Not only safe guards the drives but transmissions too.




Mine are set up to slip anything above 900ft/tq



http://www.marinedesigncorp.com/2014.html
ICDEDPPL is offline  
Old 12-03-2016, 07:44 PM
  #10  
Registered
iTrader: (3)
 
Join Date: Jul 2004
Location: chicago
Posts: 11,332
Received 71 Likes on 39 Posts
Default

Originally Posted by ICDEDPPL
^^^ agree.
Not only safe guards the drives but transmissions too.



Mine are set up to slip anything above 900ft/tq



http://www.marinedesigncorp.com/2014.html
and the crankshafts
MILD THUNDER is offline  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.