Probably stupid autopilot question!

[jwilson]

How do they cope with the fact that these drives are not waterproof?

Pete

One on a Rustler 36 had it very neatly mounted in the undercover lazarette cutout area where the tiller goes between transom and cockpit. The other had a rather ugly box built on the aft deck to cover it with an arm out to the rudder head. That one might have been hydraulic.

 

[DownWest]

Why not have a similar setup as an aircraft rudder with trim tab.For autopilot lock the rudder central with some sort of quick release thing, then the tillerpilot operates a large trim tab on the rudder.So the tillerpilot is permanently fixed to the top of the rudder.I suppose it depends on the boat design!
View attachment 42982

Can't do that: If you lock the tiller, then the trim tab becomes a rather small rudder. Aircraft have two sorts of tabs, one is a type of servo to ease the load on the controls, the other to preload the control due to weight or aerodynamic loads. (as you go faster, the centre of lift moves back on the wing, so the trim tab is moved to apply more down force by the elevators).

Just been through this with a friend's boat. Tiller steered 34ft ketch, around 13 tonnes. Loads are not a problem, as he can trim the sails to self steer. Using the trim tab the 'helm' is finger light. So we made up a wind vane to operate the tab and he has a small tillerpilot which also moves it. But you can't mount the TP on the rudder, as the internal compass would get comfused as the tiller moves. It has to be mounted off the rudder and a linkage fitted that allows for the action to pass the rudder pivot without changing the tab. A bowden type cable can do this, but he is using something else.


Our company yacht, a big ketch, had two hydraulic steering positions and a hydraulic ram AP. The ram sprung a leak and the system gently drained down. They carried spare oil and an emergency tiller. After the oil ran out, they tried to rig the tiller, but....dropped it overboard. So they lost the two steering positions and only just made it to port with the AP pump steering as it was the lowest part of the system. I asked what would have been their next plan. Drop the sails and motor, using the engines to steer.

 

[Tranona]

Just been through this with a friend's boat. Tiller steered 34ft ketch, around 13 tonnes. Loads are not a problem, as he can trim the sails to self steer. Using the trim tab the 'helm' is finger light. So we made up a wind vane to operate the tab and he has a small tillerpilot which also moves it. But you can't mount the TP on the rudder, as the internal compass would get comfused as the tiller moves. It has to be mounted off the rudder and a linkage fitted that allows for the action to pass the rudder pivot without changing the tab. A bowden type cable can do this, but he is using something else.

Using a tiller pilot in conjunction with a windvane is quite common as the loads are much less than using the main rudder. However, the OPs question is more about how to arrange dual helms when the main helm is a tiller, and still maintain the "feel" of a tiller. No easy solution as the choice is either steering functionality which would require linked tiller and wheel, or remote autopilot facility to allow watchkeeping and course changes from a sheltered position. The latter might be the better compromise given his desire to have a tiller rather than a wheel for the main helm.

 

[DownWest]

I was more replying to the other bits about tabs. Perhaps a system with the internal helm clutched onto the rudder stock below decks. Have to be a good clutch system though.

 

[johnphilip]

I was wondering if there was a way to have an autopilot permanently installed on a boat which is steered by a tiller. The idea is that you could have two helm positions, one controlled by the autopilot, which would allow you to get in out of the elements. The only autopilots I know for a tiller steered yacht are tillerpilots and so they are not permanently set up. I suppose you could set it up each time you want to steer from the forward helm but it would be more of a faff.

Is there any other way to have more than one helm position? I like tillers so the primary helm needs to be one. I know about extensions etc but that doesn't work in this scenario. This is all theoretical as it is just ideas I am having for a potential future project to build a ~40 foot boat.

Thanks

How about the Hunter Pilot as on this link, I believe there is a clutch on the wheel steering. Add an Autohelm and have the best of all worlds.http://www.yachtsnet.co.uk/archives/hunter-pilot-27/hunter-pilot-27.htm
It looks on the last picture as though there is a short operating arm projecting from the the transom by the rudder.

 

[single]

Can't do that: If you lock the tiller, then the trim tab becomes a rather small rudder. Aircraft have two sorts of tabs, one is a type of servo to ease the load on the controls, the other to preload the control due to weight or aerodynamic loads. (as you go faster, the centre of lift moves back on the wing, so the trim tab is moved to apply more down force by the elevators).

Just been through this with a friend's boat. Tiller steered 34ft ketch, around 13 tonnes. Loads are not a problem, as he can trim the sails to self steer. Using the trim tab the 'helm' is finger light. So we made up a wind vane to operate the tab and he has a small tillerpilot which also moves it. But you can't mount the TP on the rudder, as the internal compass would get comfused as the tiller moves. It has to be mounted off the rudder and a linkage fitted that allows for the action to pass the rudder pivot without changing the tab. A bowden type cable can do this, but he is using something else.


Our company yacht, a big ketch, had two hydraulic steering positions and a hydraulic ram AP. The ram sprung a leak and the system gently drained down. They carried spare oil and an emergency tiller. After the oil ran out, they tried to rig the tiller, but....dropped it overboard. So they lost the two steering positions and only just made it to port with the AP pump steering as it was the lowest part of the system. I asked what would have been their next plan. Drop the sails and motor, using the engines to steer.

Well thats why i said similar.It does work and thats why its 'similar'.You have to lock the rudder (for the reason you said) and rely on the mini rudder (trim tab) for small autopilot steering adjustments.