Tiller pilot or linear drive

[Maartster]

We have a HR34 that came with an tiller pilot and a ST4000+ course computer. We are considering to replace the tiller pilot with a linear drive autopilot mounted below deck.

Advantages:

1. more space in cockpit because tiller can be lifted up while sailing
2. more robust and not exposed to elements
3. more powerful in extreme circumstances

Disadvantages:

1. extra power drain because of clutch (1A x 12 V = 24 AH)
2. more resistance when steering manually
3. extra cost and more expensive

According to the HR dealer we can’t use the ST4000+ for the linear drive because it can not deliver enough power. A set with drive and control unit cost about 2700 EUR ex. installation. Does anybody have experience or advice?

[roverhi]

Why not get a windvane and use the autopilot for powering?? You can get a used Monitor for around $2,000. Windvanes are way less trouble than an auto pilot and don't need to be fed. Of course, you'd still have the tiller in position with a pendulum servo vane unless you shortened the tiller to work primarily with the tiller pilot/vane. Rig up an extension to be installed when hand steering.

[Maartster]

I thought about that as well. If you use a windvane with an auxiliary rudder like hydrovane you don't need a tiller and wires and just need to lock your tiller in upright position. Disadvantage of windvane is less accurate course control with coastal cruising and a device mounted to the stern.

[Neptune's Gear]

Below deck APs are absolutely the way to go for serious use. You CAN use your existing AP. Just use a Mosfet based H bridge to supply the ram. like this
I had one working like this for over 10 years!

[Rustic Charm]

Another advantage if the linier drive is that they can control a larger tonnage vessel too. Unfortunately with my transom hung tiller there's no way of getting it blow deck.

[Maartster]

Originally Posted by Neptune's Gear

Below deck APs are absolutely the way to go for serious use. You CAN use your existing AP. Just use a Mosfet based H bridge to supply the ram. like this
I had one working like this for over 10 years!

This is an interesting option since we can then still use the tiller drive as a backup without any modifications to the autopilot.

Any suggestions on which linear drive to use? I know there is Jefa and Raymarine. They are about the same price and have similar power drain for the clutch.

[Neptune's Gear]

LOTS of options on a drive, or even better a hydraulic pump and ram. Hydraulics are the most reliable by a long shot.
The Navico (Lowrance/Simrad/B&G) solution would be a RPU80, or RPU160 I'd expect for a vessel this size. Then a ram to suit. Look in the book for the pump units to size the ram, any hydraulics place can do one. My custom one was cheaper than any of the off the shelf ones, takes up less space, is WAY stronger, and has reliably steered my boat for over 30,000 NM.
Any manufacturers reversing hydraulic pump can be used, you are not restricted.

[Formosa46AK]

Originally Posted by Maartster

I thought about that as well. If you use a windvane with an auxiliary rudder like hydrovane you don't need a tiller and wires and just need to lock your tiller in upright position. Disadvantage of windvane is less accurate course control with coastal cruising and a device mounted to the stern.

I hope noone thinks I'm trying to steal this thread, but this is pretty much my situation. I'm just now sending in the last couple of thousand for a new Hydrovane for my Formosa 46 mid cockpit with displacement of 17 tons. I want to send final directions for all the final options including the option to attach a autopilot tiller to the Hydrovane for steerage when running the engine while raising/lower main and at times (unfortunately) of no wind.

My question is: Which autopilots for similar windvane steerage are others using or recommending? I've found what I think is a reasonably good unit - a Raymarine EV-100 Tiller Evolution Autopilot - T70153 Raymarine EV-100 Tiller Evolution Autopilot T70153
though it is rated for a maximum of 7.5 tons. My boat is 16-17 tons. Since one can hand steer the wind vane in the event of loss of rudder with a short emergency rudder, it seems this unit will be satisfactory.

Anything else I have to think about regarding auto steering?