Tique feels slippery after new prop; rudder play?

New Prop! Acme 1214 (12.5 x 13)







The 12.5 x 13 CNC 3 blade is night and day when compared to my cast federals (12x14 & 12x15). I now have amazing hole shot while maintaining 50 mph top end @ 4300 rpm. My only complaint is if I'm trying to drive straight the boat feels like it's on ice above 20mph.

Now I can't really blame it on the prop, but I think the increased flow over the rudder has exposed some other issues.

If I were to guess I'd say the "on ice" feeling is the rudder flip-flopping between R&L which leads to a driver correction + compounds the problem. While the steering arm is tight on the rudder, I still have 1/2" - 3/4" of total play which appears to be coming from the linkage, cable & steering box. All loose parts aside I don't remember feeling this R/L drift before installing the new prop. Also if I stay in a slight turn (loading the rudder a bit) the side to side drift goes away. Long & short it gets squirrely at neutral rudder.

Not that it directly affects it, but when I pulled the floor board to check on the steering play I found the stuffing nut had backed off enough to be turning with the rudder. I tightened it down, but it didn't effect the play.

1.) When searching for info on this problem I found that some rudders are tuned to give the steering system some pre-load. Is that an option while I work on tightening up the components?

2.) The rudder has some all around play even when the packing nut is tight. Is it worth trying a repack or should I be expecting to do some machine work on the rudder & stuffing box?

3.) Just how tight should the stuffing nut be. Meaning I tightened it down pretty darn good and still had free-steering.   Should the packing be good enough to bring the rudder to a stop then you back it off?

Andy,
You are correct with the rudder tuning adding preload. Get back to us after you tune your rudder.

Andy,
Tightening the port packing will stiffen up the steering but you will still have the slack when turning the helm wheel. Tuning will keep the tension in one direction so you won't get the back and forth drifting.

Rudder tuning is done by grinding a bevel on ether the forward or aft edge of one side of the rudder. It sort of creates an aerofoil.