I have done successful installations with and without shaft brushes so I am not completely sold on them. But you have to do your homework upfront with periodic measurements to insure the integrity of your galvanic protection system, as well as using the right size/amount of quality zincs. The shaft zincs do not have as much impact as you suspect, especially in regards to in-flow to the propeller. The Strut Barrel and Strut Leg are more crucial to propeller in-flow, as are the locations of lifting strakes on the bottom surface. Drag is negligible on an 30 knot vessel.
So, many later I'm shopping for a set of shaft brushes for our Bertie. I'm not in a hurry over the Pro-Mariner model. Question; Is there any other brand or mfg that may make a longer & more substantial wiper and arm? On my swamp budget? I did find the Electro-Guard Brand. I'll go there if I have to. Not a budget item though.
Yes, They push that Electro-Guard shaft Brush. I already have a note to them asking them for specs. Seems that may be the only brand left on the market, it is expensive yet nobody on line comments how long the dam thing is. You would think this would be a simple and cheap option. FM I'm already scheming to build another set.
Correct part number is now 20035-1 Find 2 in stock with either part number for me. My leads report discontinued. Further, I have had these (ProMariner) in my hands before, Flip if I can remember how long they were. I don't remember them having much length. I have some air space to cover in ole Bertie. No spec on line for either brand.
I had recently looked for a set also and couldn't find anything but the Electro-Guard shaft Brush. But theirs states only good for up to 1.5" shafts. Don't know why it wouldn't work though.
Found some brushes. Looking for a rod or skinny plate to use for the finger. Think I'll make my own thingies. How does this brush compare to others? I think it may be longer that what the promariner had. https://www.mcmaster.com/65705K53/