Tiller pilot recommendations?

[Mirelle]

What make and model would you recommend for a 10 ton, long keeled, cutter?

Well balanced, but more of a Land Rover than a Lotus - you can let go of the tiller for quite a long time (hours, if close hauled!) but it needs a good shove when it does need shifting.

I've gone for years without one, and they all seem to have changed!

 

[tome]

Shock, horror

Good heavens man! First you talk of fitting a VHF set and now this. Have you no shame?

 

[trouville]

Re: Shock, horror

id like to ask the same question! everything has changed and i also havent needed an autopilot
Now im buying a long keeled well balenced Folkboat and would like a tiller pilot as well. but for a 2 Ton 8 meter boat.

Ive also added hand held vhf hand held GPS hand held telephone and hand held PDA for wi-fi email! that way when i go into town i dont have to close up!

 

[pvb]

Choice is a bit restricted...

There's not a lot of choice in the market now, is there? Basically Simrad or Raymarine, neither of which claim to offer anything suitable for a 10 ton boat, so warranty cover might be compromised.

You say the tiller needs a good shove - had you thought of measuring the force needed? Could be done fairly easily with a spring balance at the recommended tiller pilot attachment point. This would indicate whether the bigger tiller pilots might be able to cope (both the Simrad TP32 and the Raymarine ST4000+ offer around 85kg max thrust).

 

[Shantyman]

A few years ago I planned to build a 12 ton 36ft cutter and had given some thought to this self steering problem.

Trim-tab self steering was much in favour at that time and was well discussed in magazines at the time. See also Moitessier's books.

I reckoned that a conventional tillerpilot could be coupled up to the trim-tab by using a linkage to reverse the thrust.
It might also be possible to alter the wiring to reverse the thrust.

If the boat is reasonably well balanced I reckon you could steer quite a big boat by this means.

Of course you need a stern-hung rudder and a trim-tab!
And this is only a theory!

Nevertheless I might try it out sometime on my Dutch Barge!

Regards.

Shantyman.

 

[Anonymous]

Trim tabs have been used on aircraft control surfaces for decades. The real downside is the added complexity especially when the bits are underwater where it is difficult to inspect and maintain them.

 

[tillergirl]

I have just had my Navico (aka Simrad) TP30 (now the 32) repaired by Simrad after the Fluxgate Compass failed. It has plenty of power and I have never had any problem with it coping. But then I don't carry a lot of weather helm. Its fast enough as well and the automatic gain to prevent unnecessary to and fro work seems to work well. Whether the Fluxgate failure was unreasonable or not I can't really tell because I bought it second hand. Like the RayMarine one it can be interface with windgear (well you never thought you'd get a tillerpilot so maybe that's next) and steer to wind. Does that on the wind very well. I'm not that impressed with the Autotack feature but that's probably because TG isn't that closewinded (it goes to a 100 degree angle I think).

When I was researching the purchase, I was impressed with the lower power comsumption of the Navico model. Having been with a boat with the RayMarine 2000 model, the Navico was quieter as well although the RayMarine thing was hardly quieter.

 

[Shantyman]

Re: Tiller pilot recommendations. LEMAIN

Lemain, The trim-tab system is particularly uncomplicated when compared to some systems. You only need to have one bearing under water. Not a big problem I would have thought.

Regards,

Shantyman.

 

[Neil_M]

I have one of the mid range Raymarine TPs fitted & whilst it responds quickly to the directional whims of a fin keeler I doubt it would have the power to shift your tiller. Might ask my good friend Art (Deben Marine) if he's come across any similar applications in his work - he lived aboard a heavy long keeler, Namanda, a while back & had an autopilot fitted, may have some ideas... Do you envisage using it for short periods or extended offshore passages?

 

[Anonymous]

Re: Tiller pilot recommendations. LEMAIN

[ QUOTE ]
The trim-tab system is particularly uncomplicated when compared to some systems. You only need to have one bearing under water. Not a big problem I would have thought.

[/ QUOTE ]Isn't there necessarily an underwater actuator, push-rod or bowden? How else is the tab controlled?

 

[philip_stevens]

Re: Tiller pilot recommendations. LEMAIN

It would be like a second rudder hanging on to the back of the main rudder. You tell the autohelm to move the trim tab in the opposite direction to what you intend the rudder to go.

I don't remember the mechanics of it, but it can, and has been done, as shown in an article in PBO a few years ago.

Autohelms can be made to work in reverse, by installing it on one side of the boat, and telling it that it is on the other side. This facility of for normal starboard fitting, or if it has to be fitted on the port side.

 

[Anonymous]

Re: Tiller pilot recommendations. LEMAIN

[ QUOTE ]
It would be like a second rudder hanging on to the back of the main rudder. You tell the autohelm to move the trim tab in the opposite direction to what you intend the rudder to go.

I don't remember the mechanics of it, but it can, and has been done, as shown in an article in PBO a few years ago.

[/ QUOTE ]Sure, I know how it's done - as I said earlier, it was done decades ago on aircraft. It has the effect of being a servo. The problem with it is that it requires parts underwater where they cannot be inspected or maintained frequently. Even very large yachts manage perfectly well without that added complexity so why fit it? The fact that it is a curiosity rather than mainstream marine engineering speaks for itself.

 

[philip_stevens]

Re: Tiller pilot recommendations. LEMAIN

I get what you are saying, but don't we all have this problem by just having a rudder?

If his boat is too heavy for a normal Autohelm, "but it needs a good shove when it does need shifting", maybe this is the only way he can go to reduce the torque required to steer the boat.

Yes, I agree, it is another thing hanging off and into and under the water, with the inherant problem of wear.

 

[Anonymous]

Re: Tiller pilot recommendations. LEMAIN

We are stuck with having a rudder with its bearings, but trim tabs add another level of complexity. Furthermore, since there is 'gain' in a trim tab system it could conceivably become unstable.

His boat is not too heavy for a normal autohelm - he wants to use a tiller-pilot style but there does not appear to be one rated for his boat. The ST7000 with hydraulic or linear actuator would handle it easily - albeit at a cost.

The problem is not really wear; for most people it would be corrosion and marine life clogging it up.

It is a real problem for him since to go from tiller-pilot to the full quadrant-driven autopilot has considerable cost and engineering implications but I don' t think that trim tabs are the right way to go to solve that problem. If I was in his position I would phone Raymarine at Portsmouth and ask for their techical department. They are very helpful and know their products inside out.

 

[Mirelle]

Art Butler - excellent idea, thanks

He did all Mirelle's electrics anyway; natural choice.

He's also a very talented fiddler - by which I mean he plays the violin in a folk group!

 

[Mirelle]

Spring balance

I had not thought of that. Really good idea. I'll try that before going further.

 

[Shantyman]

Re: Tiller pilot recommendations. LEMAIN

One of the reasons Moitessier went for the trim tab was it's simplicity (in the wind driven application). He researched it pretty thoroughly.

As I see it the advantages of the "Tillerpilot" on Trimtab against a "conventional" heavy duty system are as follows:
1) You can use a relatively less powerful tiller pilot.
2) This will in turn use less electricity.
3) Cost of trim tab + pilot may even work out less than heavy duty system
4) For a modest additional expense you can have windvane steering as well!

Regards,

Shantyman.

 

[Anonymous]

Re: Tiller pilot recommendations. LEMAIN

Are you saying that the tiller pilot somehow drives the trim tab? I can't see by what physical means or under what software control that would be possible.

Something has to control any trim tab and that something must be connected to it with some form of linkage.

 

[Shantyman]

Re: Tiller pilot recommendations. LEMAIN

Yes. The tillerpilot is connected to the trim tab in the same place as the windvane would be connected.

See previous but one post in this thread from philipstevens.

Rgds.

Shantyman.

 

[Anonymous]

Re: Tiller pilot recommendations

[ QUOTE ]
Yes. The tillerpilot is connected to the trim tab in the same place as the windvane would be connected.

[/ QUOTE ]I can't visualise this. The tiller pilot is a device that is secured to a fixed point at one end and has a telescopic arm that extends and retracts according to an error signal derived from an internal compass and, possibly, an external GPS input. The movement of the tiller arm - and the control charateristic - is designed to be suitable for the sort of range expected of typical tillers connected to a rudder. How is the end of the tiller arm intended to be connected to the trim tab? Is this an available part or some custom design?

[ QUOTE ]
See previous but one post in this thread from philipstevens.

[/ QUOTE ]Which part of his post are you referring me to, and why?