tiller pilot advice

[fnuttersny]

I have been using 15 hp outboard on my 79 H27 for the last two years. I just installed a new replacement RC8D diesel and was surprised at the "weather helm" effect produced by this torquey engine. At 3/4 throttle it is pretty strong and if I let go the boat veers of 90 deg. immediately. Question: will tiller pilot device handle the pressure since most require placing 18" forward of rudder post. I tried steering at that position by hand doing 6kts with diesel humming along and don't see how a tiller pilot will compensate. I can't imagine this is unique to my set up. Advice requested.

Cheers Frank

 

[Benny17441]

That torque response is not normal; check that engine is not overfueling and that the prop is properly sized and clear of marine growth.

 

[kloudie1]

Check that the engine side-to-side alignment is where it should be.. Ya might have to move the whole engine and transmission (all 4 mounts) to port or starboard slightly to compensate while under power. (point the prop slightly opposite the tiller direction of swing)
The autopilot most likely can handle it but you don't have to stick perfectly to the 18" dimension as long as you can get a pretty good "swing" on the rudder. If you are concerned, 20-22 inches will probably help and still allow plenty swing .. I sail a catamaran that has the tillerpilot at about 36 inches and that is too far out when in light air. At speed (over 4 knots for the cat), when the rudder doesn't have to move much, it works very well.

 

[svchickadee]

On reason to install with the specified distance between the rudder post and
tiller pin is to allow the tillerpilot to accurately change course with 1%, 10% and tacking selection. This distance is how the device determines the degree to move the tiller.

 

[fnuttersny]

Didn't realize that about tiller pilot but makes sense. Don't quite understand "over fueling" but it seams I would see oil traces in the exhaust. As for miss alinement ... this is a direct replacement and lined up perfectly plus I have very little lateral play in way of shaft/stern tube. Even so if entire propulsion was off set it would only aid in centering tiller but shouldn't effect torque action in my opinion. However, the prop is probably not a good match. I'll get tachometer and see what kind of rpms I get at various loads..

 

[jviss]

With all due respect, the over-feuling and alignment responses are not it. On the alignment in particular, you can't move the engine around to effect a change in the torque direction of the prop; the alignment is built into the boat at the factory, and the engine should be properly aligned to the unloaded prop shaft. I can't imagine where that idea came from.

As far at the 'torque' feeling on the rudder - that's just how these things feel!

Don't worry about the tiller pilot, should be no problem.

 

[fnuttersny]

I think part of the effect is me. The out board had very little torque being located close to the service and I probably didn't remember what it was like running under diesel. I never operated to old one above about 1/2 throttle because it was really worn and would throw oil. The new engine even though only 8hp has a surprising amount of power when throttled up. thanks for help everyone ...cheers Frank

 

[Chris Patterson]

Frank, I run an ST2000 on my 22', at the 18" suggested alignment, and think it would break the tiller if I "grabbed" it, to try and override it. I sail this boat in some pretty stupid weather conditions, and although I would like to see it make some faster corrections at times, I know it's doing its job, sans me sitting with my legs braced on the other side of the cockpit, holding the tiller. It's strong.
And if I COULD NOT buy another one, I wouldn't take five thousand dollars for it. It simply made sailing into another whole dimension. A good one..

 

[kloudie1]

Jviss.. yes, the engine can be slightly moved as long as that is where it was supposed to go.. My comment was about insuring that the engine and prop shaft are in fact aligned correctly with the cutless bearing.. and that the cutless is where it is supposed to be..
svchickadee, The tillerpilot has enough "adjustability" to handle a small deviation from the optimal 18" dimension.. I wouldn't go shorter but a couple of inches longer will not confuse the little dear.. ya have to be more careful about centering the push-rod at neutral rudder, 'cause you'll be using a little more of its travel..
Since the outboard was not providing prop wash over the rudder, the feel will be much different with the diesel putting a lot of turbulent water directly over the rudder..
Fnuttersny, that was quite a find on the engine.. amazing ! good luck with it..

 

[MrBill_FLL]

I don't think the tiller pilot will break. something else, maybe. but even my TP10, is very robust.

 

[fnuttersny]

I have about just under 1/8 of vertical play in shaft as this is about how far it dropped when I disconnected it. Is this a typical? I plan to replace bearings etc. at next haul out. I notice only a slight "drumming" at a given rpm but can find sweat spot and smooths out. Now that you mention it Claude, I will check alignment with feeler gauges and dial indicator. I didn't think it was that critical for some reason but I intend to run this little bugger briskly so I really need fine tune the drive. Thanks for pointing it out. Also, who's had the best luck with any particular tiller pilot? BTW your right that was a one in a million find I never get luck that way so as I'm dismantling old motor an Iron Worker from the new Freedom Tower paddles by in a kayak an presto engine is in the back of my truck.

 

[Chris Patterson]

Again, I have the Raymarine ST2000. Never having used another one like the 1000, or the TP10, I studied about this HARD! I put it on a Catalina 22, so weight was not the issue, but the response time on throw to throw did. A chimp could install it, (which is good), and first time out, it performed flawlessly. I was a tad apprehensive about the Raymarine, after reading at length, (and I kinda hate to say this, but it is, what it is), some dunderheads website about the trials and tribulations of this unit. It turns out that my opinion on pilot, and owner that blasted this unit so badly was correct. The pilot is wonderful, and the writer is, well, you get the idea...
I did as usual spring the extra hundred bucks for the 2000, over the 1000 because I didn't want to think later, "I wish I had gotten the larger/faster version".
And I'm an overkill engineer. I have never once gone wrong in over engineering anything.

Over thought it maybe...

 

[kloudie1]

My experience with the tillerpilot is the same as Chris... It is a great little unit.. Without it, the 27' Stiletto catamaran would be almost impossible to singlehand .. The pilot is on the tiller cross link between the two rudders, which is about 3 feet from the pivots..about double the recommended position.. This is too far to allow slow speed tacking, but it works fine for motoring and for sailing.. tracks better than many helmsmen.. The thing was a true "plug and play" installation and has been easy to use .. Not recommending ya go that far, but like I said, a couple inches more probably will not make a noticeable difference ..

Edit: Ya should have a bit more than 1/8" play at the coupling, but I am not familiar with that boat. Usually, the coupling is pushed all the way down 'till it hits the stop, then all the way up then side to side.. to find the center of the log. then the coupling is supported there and the engine is aligned on that point ..

 

[fnuttersny]

Looks like easy enough to check. I' ll start shopping for a tiller pilot also..thanks again.

 

[Charlie Jones s/v Tehani]

You might look into adding a fixed trim tab on your rudder to offset that helm. Delivered a yacht last feb that had that problem- a small trim tab, adjusted correctly, fixed it.