CONTESSA 32 ASSOCIATION Homepage
Forum Home Forum Home > Technical Help > Electrical Systems, Navigation and Safety equipment
  New Posts New Posts RSS Feed: bonding sys / shaft brush
  FAQ FAQ  Forum Search   Calendar   Register Register  Login Login

bonding sys / shaft brush

 Post Reply Post Reply
Author
Message
Tazling View Drop Down
CO32 Members
CO32 Members
Avatar

Joined: 16 Jan 2013
Location: Cortes Isl BC
Online Status: Offline
Posts: 23
Post Options Post Options   Quote Tazling Quote  Post ReplyReply Direct Link To This Post Topic: bonding sys / shaft brush
    Posted: 22 Aug 2013 at 1:49am
My JJT CO32 came with 2 zincs attached one on either side of the keel, with bolts through into the sump walls, and "mystery wires" leading off into the snakes' nest of hoses and wires heading aft.  I have a feeling that they are attached, eventually, to a shaft brush that rides on the very small exposed section of drive shaft between stuffing box and gearbox.

Question:  if I have (and I have!) attached a sturdy prop zinc externally, do I still need the shaft brush?  I have a long-standing distrust of bonding systems :-)  If my prop zinc is beefy and well attached, can I dispense with the keel zincs?  They don't seem to have been doing all that much for the prop anyway -- the bronze shows telltale pinkish freckles and mottling.

inquiring minds...

BTW, my CO32 squeaked past an Alberg 35 on Monday in an informal local race.  The air was light and fluky (going to weather, thank goodness for small mercies) and it was tetchy, gritted-teeth helming but eventually, slowly, despite getting a late start and having a quarter mile or so to catch up, I was ahead of my esteemed rival round the first mark.  That was a *good* day :-)  The A35 had a taller rig, more waterline, deep local knowledge, and better sails... so I am not sure what got me into the lead -- dumb luck in the lulls and puffs, or (I would like to think) better strategy, rigorously attentive steering, and a fine boat :-)  Hooray Contessa!
..... Bound is boatless (wo)man .....
Back to Top
George Isted View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 08 May 2009
Location: Solent
Online Status: Offline
Posts: 375
Post Options Post Options   Quote George Isted Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 2013 at 12:21pm
Depending on how much metal there is in the water (marina mooring piles), some areas seem to need more anode protection than others.   To me it seems a bit of a black art and relates to shore power being earthed to the anodes also. 
 
Most of the racing boats do away with the hull anode but hang one over the side when moored up, I presume this is bonded to the underwater metal fittings.
 
I myself only have a prop anode that lasts around 18 months and no hull anode but the boat is not left connected to shore power.  The blakes seacocks that have been removed for inspection all seem to be in excellent condition so not been eaten away yet.
 
 
George Isted
www.solentboatbutler.co.uk
Contessa 32 "Concerto"
Co32 Class Measurer and ex Class Captain.
Back to Top
Conte View Drop Down
CO32 Members
CO32 Members
Avatar

Joined: 07 Dec 2012
Location: Italia
Online Status: Offline
Posts: 8
Post Options Post Options   Quote Conte Quote  Post ReplyReply Direct Link To This Post Posted: 11 Sep 2013 at 8:49pm
Hi all,
 Seacocks (mine are all in Marelon) and the engine apart, there is something else that needs to be connected to the anode?

Piero
Back to Top
samourai View Drop Down
CO32 Members
CO32 Members
Avatar

Joined: 28 Feb 2016
Location: Greece
Online Status: Offline
Posts: 22
Post Options Post Options   Quote samourai Quote  Post ReplyReply Direct Link To This Post Posted: 18 Mar 2019 at 6:58pm
Hi everyone, 
I am at the moment fitting a new shaft and fixed 3 blade prop (14x8") on our CO32 and I realised there is no space to fit a shaft anode. Obviously this is because of the rudder which is behind. So the question is how am I suppose to protect the stern gear from electrolysis ? Apparently there is no external anode but I really think I should better fit one. Does anybody could give an advise on how to connect the shaft+prop on an external anode ? Is there any other part of the boat which should also be connected to this anode ? CO32 "Samourai" 
Back to Top
Keny View Drop Down
CO32 Members
CO32 Members


Joined: 29 Aug 2010
Online Status: Offline
Posts: 77
Post Options Post Options   Quote Keny Quote  Post ReplyReply Direct Link To This Post Posted: 21 Mar 2019 at 4:18pm
It depends on your coupling. If it's an R&D one it will have a carbon brush which connects the shaft to the gearbox and ultimately the sacrificial anode which you should sensibly have.
If it is one of the rubber couplings you can bridge it with a flexible s/s wire or some sort of brush box which can be connected straight to the conductor.
The anode will also be connected to the engine/gearbox to protect aluminium castings etc.
The Blakes sea cocks don't need to be connected since they are made of a single metal.
Ken

Back to Top
samourai View Drop Down
CO32 Members
CO32 Members
Avatar

Joined: 28 Feb 2016
Location: Greece
Online Status: Offline
Posts: 22
Post Options Post Options   Quote samourai Quote  Post ReplyReply Direct Link To This Post Posted: 21 Mar 2019 at 8:46pm
Hi Ken, 
Thanks a lot for your explanation. It makes things a bit more clear on this subject. As George said in his post: "its a bit of a black art"... On my CO32, the shaft is directly connected from the coupler to the gear box, there is no "flexible coupling". As I understand, I will have to fit a carbon brush device & an external anode to be on the safe side. 
If anybody has a photo of this "carbon brush" arrangement in the engine room, that will be very welcome ! 
Back to Top
Keny View Drop Down
CO32 Members
CO32 Members


Joined: 29 Aug 2010
Online Status: Offline
Posts: 77
Post Options Post Options   Quote Keny Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2019 at 9:09am
Sounds like a flexible coupling wouldn't go amiss as well. The current trend seems to be the rubber sort.
However if your shaft is directly connected to the gearbox and you fit a sacrificial anode, that is all that's required.
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down