 |
29-10-2009, 04:34
|
#1
|
|
Registered User
Join Date: May 2009
Location: miami
Boat: Spindrift 43 SV Falkor
Posts: 236
|
Where to Put Zinc on Prop Shaft?
Im finaly done with my out of the water projects, all I have left is to put a zinc on before the boat goes swiming on friday. Is there a reason Not to put the zinc bewteen the strut and the hull? The zinc I got is about 2.5 inchs long and wont fit between the prop and the strut.
|
|
|
|
29-10-2009, 04:57
|
#2
|
|
Registered User
Join Date: Feb 2007
Location: Caribbean
Boat: Jeanneau 57
Posts: 2,279
|
There is a good reason to do so - if, for some reason, your prop shaft gets separated from your transmission then a bolted on zinc forward of the strut might just keep the shaft from dropping off the boat.
|
|
|
|
|
29-10-2009, 05:34
|
#3
|
|
Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,384
|
Zinc shaft anodes are often placed forward of the strut, because of the limited exposed shaft distance between the strut bearing & propeller hub (see ‘D’ in diagram).
Don’t place the zinc hard against the strut, which would block lubricating water flow through the bearing.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
|
|
|
|
|
29-10-2009, 05:55
|
#4
|
|
Registered User
Join Date: Mar 2009
Location: Hobart
Boat: Portobello - a Walter Knoop designed "DOVEN 30"
Posts: 231
|
...and if your motor has soft mountings there is considerable movement of the shaft forward and backward as the motor moves. Leave space for this movement.
__________________
Love the journey!
|
|
|
|
|
29-10-2009, 06:19
|
#5
|
|
Registered User
Join Date: Mar 2006
Location: Tampa Bay area, USA
Boat: Beneteau First 42
Posts: 3,961
|
The zinc should be placed just a few inches forward of the strut, leaving only enough room between the strut and the zinc to allow water flow through your cutlass bearing. The density of zinc's is not uniform and if mounted midway between the strut and shaft log (where the shaft penetrates the hull) may have a tendancy to cause the shaft to vibrate in the manner of an unbalanced tire, particularly if there is a fairly long run between hull and strut. We discovered this on our old Cal 2-29 and found the same to be true on our First 42. Also, ensure that there is a good metal to metal contact between the zinc and the shaft.
FWIW...
__________________
"It is not so much for its beauty that the Sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."
|
|
|
|
|
29-10-2009, 07:12
|
#6
|
|
Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,384
|
Quote:
Originally Posted by svHyLyte
The zinc should be placed just a few inches forward of the strut, leaving only enough room between the strut and the zinc to allow water flow through your cutlass bearing...
|
Or even less.
I'd think about 1/2 (or even 1/4) shaft diameter to be sufficient.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
|
|
|
|
|
29-10-2009, 08:26
|
#7
|
|
Registered User
Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,515
|
Boy.... I bet it feels good to be down to putting the zinc on and knowing you got it all buttened up correctly......... and of course getting her wet!
|
|
|
|
29-10-2009, 08:37
|
#8
|
|
Registered User
Join Date: Mar 2006
Location: Fort Myers FL
Boat: Irwin 40
Posts: 878
|
The others are correct about placement but I will add polish the shaft under the zinc with a scotch pad prior to putting the zinc on and before the final tightening of the screws tap it on both sides with a hammer and then re-tighten the screws.
Enjoy floating again 
Wayne Canning, AMS
projectboatzen.com
|
|
|
|
|
29-10-2009, 08:53
|
#9
|
|
Moderator Emeritus
Join Date: Sep 2007
Location: Eastern Tennessee
Boat: Research vessel for a university, retired now.
Posts: 10,406
|
Purely from an electrical standpoint, it makes no difference. Mechanically, it can. I put mine a couple inches ahead of the strut to make sure the cutlass bearing has proper water flow.
__________________
David
Life begins where land ends.
|
|
|
|
|
29-10-2009, 09:23
|
#10
|
|
Registered User
Join Date: Nov 2008
Location: West Coast, BC , Canada
Boat: Cascade
Posts: 595
|
You may want to put 2 of those on. How many were on before, how long were they on, and how did they look?
IMHO put two on. If they are too good next haul out you could reduce the number if you wish.
__________________
Go outside and PLAY!
|
|
|
|
|
29-10-2009, 19:36
|
#11
|
|
Registered User
Join Date: May 2009
Location: miami
Boat: Spindrift 43 SV Falkor
Posts: 236
|
I had pre installed it about 2 inchs forward of the strut. Will just latch it down there tomorrow before the big splash.
The shaft had no zincs on it when it came out.
The shaft now is new and nice and shiney but ill scothc brite it just for grins, Im nervous about going back in the water, at least on land it cant sink.
|
|
|
|
|
29-10-2009, 22:01
|
#12
|
|
Registered User
Join Date: Nov 2006
Posts: 257
|
Lots of folks put a zinc on the shaft inside of the hull as well, not to guard against corrosion, but to act as a last chance stopper should the shaft start backing out.
Brett
|
|
|
|
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Rate This Thread |
 Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Advertise Here
 Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Vendor Spotlight |
|
|
|
|
|
|
|
|
|
