I just replaced my prop with a SS Stiletto. A red piece of paper accompanied
the prop that reads:

Due to the performance enhancing nature of the design, Quicksilver Trim Tab
No. 46399A1 (or equivalent), must be used with this Stiletto Propeller on
your Mariner, Mercury, or MerCruiser engine to prevent damage and/or injury.

I'm running a 4.3L Merc on an 18.5' Reinell, and the sacraficial anode (on
the anticav plate) has no trim tab (fin) on it. It's not a big ticket item
by any means, and I have no problem doing as they say, but I'm really
curious as to why?

Any insight? Thanks.

--Mike