External Anode

[Tuggle]

The fellow I bought my boat from had external anodes hanging from the bow, mid ship and stern via alligator clips to bare metal cleats. Not knowing otherwise I'm following his practice, is this adequate, overkill, etc. Bottom looks good no signs of corrosion. Also what should the CAPAC read?

[barkleydave]

With out knowing what alloy anodes are being used it may be too much or not enough.
Normally a 32 will have keel anodes, rudder anodes, and often one on each trim tab. If not enough an external Mag. anode maybe be used in FRESH WATER!
CAPAC readings will depend on water quality, temp, and conductivity. (salt is a better conductor than fresh)
Readings at a slip should be between -.90 to -1.05. Readings in the -.80 range are not uncommon in fresh water.

check out boatzinks.com for specifics.

safe boating,
dave

[jralbert]

As Dave noted, the answer to your question is the CAPAC reading. Both low and high readings are not something to aim for. Dropping extra anodes over the side may do more harm than good. Maybe the PO was too lazy to put the proper anodes on keep/tabs/rudders. Or had other isolation problems (such as shaft not isolated).

[Tuggle]

Tabs, rudders and shafts look good, as far as I can tell. No noticeable signs of pitting or corrosion, how do you isolate the shafts? They may be and I don't know what I'm looking for.

[jralbert]

Others will be more expert on this than I..but shaft isolation comes in two key places: at the strut where the shaft must pass thru a non-metal bearing. Some uinfortunate souls have used brass bearings - a must not.

And at the plate connecting the trans to the shaft where the bolts must have a non-conducting (nylon for example) sleeve so they don't touch the metal plate. Also, a non-conducting washer under the bolt head. There's one other element at this connection that I can't describe because my brain is too tired. Someone else can step up.