use of a collar shaft zinc instead of a prop zinc?

[Mikep]

My 31S with the D4 300 will many times throw off the prop zinc well before it needs replacement. I have a professional service clean my boat and replace the zincs so I assume they know how to install properly. With previous boats I had zinc collars on my shaft instead of prop zincs. Has anyone gone this route over the prop zincs with success?

 

[Mike and Sarah]

We added a LC-7 micro thin collar. 1.5 inch shaft along with the prop nut. It did extend the prop zinc. The lc7 is the only one that will fit the narrow clearance.

 

[lproulx]

We added a LC-7 micro thin collar. 1.5 inch shaft along with the prop nut. It did extend the prop zinc. The lc7 is the only one that will fit the narrow clearance.

At other end of Ranger size spectrum, had same problem with my 21ec. Collar works great. Would have been nice if they made the prop shaft about an inch longer so a more commonly available oval zinc would fit. Only reservation was whether zinc would interrupt water flow around prop, but max speed and wot rpm same same as before. Blades near hub don't do much.

Larry

 

[Rode Trip]

At other end of Ranger size spectrum, had same problem with my 21ec. Collar works great. Would have been nice if they made the prop shaft about an inch longer so a more commonly available oval zinc would fit. Only reservation was whether zinc would interrupt water flow around prop, but max speed and wot rpm same same as before. Blades near hub don't do much.

Larry

The standard is that you don't want more than one shaft diameter of shaft length between the strut or cutless bearing and the prop. This is to reduce 'shaft whip', or torque from the prop causing excessive stress to the shaft.

 

[H28]

I thought it was just me! Lost two prop-end anodes since May 1. Ordered a prop-shaft one for the next anode change. I'll do both.

 

[MrPeet]

Can anyone share some install photos or part numbers used? I’m so sick of the prop nut and anode!

 

[BB marine]

I will add caution to the use of a collar anode when talking Ranger Tug and Cutwater. The spacing between the prop hub and keel extension where the cutlass bearing is located is minimal. Installing a collar anode in this location can reduce water flow for lubrication of the cutlass bearing which is lubricated by water. This is the reason for the anode being installed at the prop nut location. The packing gland has a water line that comes of the raw water cooling circuit. This water flows in the outboard side (cutlass bearing side) of the packing. The water is for packing and cutlass bearing lubrication when the boat is underway. The water flows down the molded tube in the keel extension and exits out the cutlass bearing after lubricating it. Placing a collar anode right in front of the cutlass bearing may restrict the water flow. The minimum (which I feel is not enough spacing I prefer 1/4") is 1/8" clearance between the anode and the prop hub and 1/8" between the anode and the keel extension tube where the cutlass bearing is installed. The maximum spacing between the shaft log tube and the prop hub,1 1/4" shaft should be no more than an 1X to 1.5 X. I do know my previously owned Cutwater C26 the spacing between the prop hub and the keel extension tube was 1". If I installed a shaft collar anode in this location it could only be 3/4" thick maximum based on minimum specifications. I prefer to have a larger gap in the event that fishing line ,sea weed..... would get fouled around the shaft. Restricted water flow will reduce the longevity of the cutlass bearing. For this reason the collar anode is not used in this location on a Ranger or Cutwater. If the prop nut anode is installed properly it will not fall off. The only reason it would be missing is it eroded away. If a collar anode is used in place it will have far less surface area for protection when compared the prop hub anode.

 

[NorthernFocus]

There's a simple solution to the prop nut anode loosening. Throw away the little star washer that comes with it and stack two lock washers under the cap screw. The problem is that as the anode deteriorates the bolt loosens. The lock washers expand as this happens and make up for the lost material. Even with the washers if you suffer a lot of electrolysis the cap screw must be tightened once in a while. I did this after losing two my first season and never lost one since.