I've found that the Tri-LUX tends to work really good on running gear if it's cleaned and primed right and the yacht cruises at below 20 knots. (Over that it tends to fall off). I feel propspeed is better than no paint on the running gear on fast boats, however, the barnacles don't just fall off of it nor does it prevent them from growing much. It just makes it easier to get them off of it. When putting traditional bottom paint on running gear, doesn't the running gear need to be primed first with a metal primer?
On our project, Yes. The hardware was cleaned brightly, washed, primed twice, washed and scuffed with a scotch bright pad, then the shrimp paint was applied. If we did not do the Bahama trip (from Jax), it could still be on the gear now. Diver reports the primer is still on the upper shaft and tabs.
Also, if there is electrolysis from a neighboring boat or your own, it will burn the paint off of the metal in a week.