Campbell sailor prop

[wind dancer]

I installed a 14x8 Campbell Sailor prop last fall when I hauled out for bottom painting.  I have noticed more power in forward gear, and no noticable loss in sailing speed, but I seemed to have lost an incredible amount of control in reverse.  My old 16x10 two blade had much more direction control in reverse.  Has anybody else noticed this?

I've also noticed an increase in vibration under way, probably due to the increased weight and torque from the new prop -- I imagine I need to realign my prop shaft if I keep the heavier prop.  I'm seriously considering going back to the two blade before our summer trip in July. . . . there may be an almost new Campbell on the market soon.

Jay

[Ken Juul]

All 3 blades will have more propwalk than a 2 blade.  The 3 blade should accelerate you faster faster in reverse so the prop walk can be minimized (unless wanted).  The key is to use bursts of power,  from N place in R give a 5-8 second burst (or until the boat starts to move backward) of near full throttle, then back to N.  Do this a couple times until the rudder becomes effective.  Then you can add additional power in R to add speed as necessary.  Because the rudder will always be less efficient in R, only keep the trans engaged when more power is needed.   Slowing down when moving forward, the prop walk is less noticable until almost stopped, a slow drag in R or bursts of power can be used.

As a rule 3 blades should have less vibration than a 2 blade.  Shaft alignment is important.  Also your engine mounts might be having a hard time with the extra thrust, contributing to the vibrations.

[Jon Schneider]

I'm not convinced about this short-blasts-in-reverse theory that everyone espouses.  I've been experimenting, and I'm beginning to believe that gentle on the governor is better.  Results still pending....

[wind dancer]

Thanks for the advice, guys.  I've tried both, and maybe I've just been spoiled in the past, but have to say that the prop walk is far worse with the Campbell prop than it was before and worse than any other sailboat I've been at the helm of.  It's probably exacerbated by the fact that I back to starboard to leave my slip, but wow. . . .

[waterdog]

Jay:

It's probably not a very good prop.  In fact, you might want to just get rid of it at a really cheap price. Maybe somebody would give you a few dollars for it and put it in their extended cruising spares inventory...

Steve

[Jon Schneider]

It's probably exacerbated by the fact that I back to starboard to leave my slip, but wow. . . .

Give up backing to starboard unless you have someone to really give you a good push astern and throw your bow out port.  Why not just make the prop walk work for you by backing out to port (and backing out all the way)?

[Bill Asbury]

Jay, I keep my c34 in the slip stern to the dock which makes it easier to get on and off from finger pier to cockpit.  Don't know your slip layout of course, but backing into the slip might be less of a nuisance for you since you and/or crew can pull the boat into the slip using dock lines once your transom is near enough to pilings to reach the dock lines.

Bill

[jmnpe]

I'm going with Ken on this one. The big blast of power followed by NO power to the prop will indeed give you the ability ( sort of, cross wind permitting ) to turn to starboard. In our previous 1991 C34 with a 3 bladed prop from 15 years ago, that technique got us out of the slip regularly. Our current 1988 with 3 blade also responds to this technique, but now it is less important in that the boat house behind us in now about 125 ft behind us rather than the 70 ft from 15 years ago.

The good thing about the 3 bladed prop and it's pronounced prop walk is that it enables you to do a mean "back and fill" that it very handy and will let you generally turn 180 degrees CW in about 1.2 boat lengths or less without breaking a sweat. With 20 kts of wind off the port bow last Saturday, turning to starboard during backing wasn't going to happen..... Just turned to port to get out of the slip and then did a 'back and fill" CW turn get turned around for the trip out of the marina. Works every time.

John

[Bruce & Sandi L]

OK John Nixon, how about a detailed description of how to do the "Back and Fill". I did a search, and could not find anything.

[Joe Kern]

http://www.videos.sailingcourse.com/pivot_turn.htm

It really works well on our boats in my experience.

Joe

[Jon Schneider]

Those instructions are a bit weird (vis a vis the video).  I don't know why you wouldn't rotate the wheel port while in reverse to help the prop walk along.

[Tom Soko]

Jon,
I've used the same technique to turn around when I had only 2 feet on either end.  Fortunately there was no wind or current, and the Admiral's eyes were as big as saucers.  I let the flag staff get within 6" of an anchor to stern, and let my anchor get within 6" of another boat's stern.  One of the few times she was truly impressed.  It works exactly as described.  The reason you don't need to touch the wheel is because you never get going in reverse.  Shift into reverse, and when the boat stops moving forward, you give it a blast of forward.  The prop wash against the rudder is very effective.  Then use reverse to stop forward progress, and repeat.  The wheel/rudder never moves, as the moderator says.

[Jon Schneider]

Thanks Tom.  Now that you've explain the prop wash effect, it makes sense.  The fairway I'm in is 50' wide, which provides a lot more than a 2' leeway, but isn't a whole lot of maneuvering space, especially when many boats poke out into the fairway.  Most of the time, I simply back out, but sometimes, with the right wind and current, I attempt to fight prop walk and swing the stern to the starboard.  Sometimes that attempt fails, and I end up having to execute a 180 degree turn-around.  I might experiment with this technique this weekend. 

[jmnpe]

The video, while explaining the basics of the "back and fill" maneuver, fails to demonstrate what I think is the most important feature. By using non-idle power ( i.e. - aggressive applications of power ) in forward and reverse, the distance moved forward and in reverse can be almost nothing - you can make the boat just pivot around the keel ( hence, the "pivot turn" ) and at a fairly impressive turn rate even from a dead stop.

The times I generally am inclined to use this maneuver combine all the things you don't want: crosswind or current from a bad direction, and not much room in which to turn. This translates into not much time to spend getting turned around, and the faster you can get turned around the less time the wind or current has to try to send you hurling into something big or hard or expensive.

I encourage everybody to go out and practice this very useful maneuver enough times and in a variety of conditions so that you become very comfortable with it. The C34 does it very nicely. You will finally come to love prop walk .

John

[wind dancer]

Update --

Yesterday while performing semi-annual maintenance, I had a friend who's a SCUBA diver check out the prop, prop shaft, zincs, etc.  All are good, so increased vibration must simply be from the heavier prop with more torque, and the need for an alignment job.  Ultimately, I'm planning on replacing the motor mounts and coupler with Vetus products (when the boat kitty is replenished), which, along with re-aligning should take care of that issue.

We were going to swap the old prop back in and take it for a test spin, but the prop/bearing puller we used broke.  Just one of those days I guess -- I had a french press explode on me that same morning! 

I'll try the techniques y'all have mentioned to counter the prop walk  -- I definitely think I've stayed on the throttle too long in reverse --  and will back into the slip from now on. . .

Thanks for all of the advice.

Jay