Below Deck Autopilots

[Pura Vida]

Rain today, 5 knts of wind, time to start another project...

The Autohelm 800 I am currently using is getting a bit flakey, steering erratically after a couple of hours. It is also challenged to keep the boat on course when the weather gets bad. So I'm looking into a replacement and am considering the ST4000T. I have read that it can be installed below deck, which is very appealing. Any experience or thoughts on a tiller steered boat with a below deck autopilot?

[Richhh]

You can mount a belowdecks autopilot to an 'auxilary' tiller. Edson, etc. offers such (bronze) auxiliary tillers - to which you mount the linear drive, the rudder position sensor, etc.

A 'good' AP would have gyroscopic sensor to measure the varying accelerations of 'sea-state' as well as fluxgate compass, rudder position sensor, etc. That stated, dont expect an electronic AP to hold a 'downwind' course very well in 'rough weather'; the gyro sensor can help, but its not that accurate.

[Alan Wheeler]

If it is tiller connected and is below deck, how do you connect, or more importantly disconnect, quickly and easily if you need to.

[AnchorageGuy]

a below decks pilot will indeed be more efficient and do a better job of steering the boat in differing conditions. It will also consume more power so you need to factor this in. Also decide on a pilot that is at least slightly over sized for your boat since we know most manufacturers slightly overstate the specs for their products. Do some research and find out what others are using and how they perform. An autopilot used for day sailing in the bay will be significantly different than one that will be used in varying offshore conditions sometimes for days at a time. Once you have gathered all of the information then you can make an informed decision as to which one you will be most satisfied with. Good luck.

[Pura Vida]

Well all the rain turned out to be way off shore but I managed two sheet bags annd a tiller cover out of the time. Thanks for the notes so far.
Richhh, I'll look into the gyro.
Wheels, Since it is below deck I'm curious how the connection works as well. I'll get an email off to Raytheon and see what they say but wanted to get some opinions of people who were using it. There must be some way to "free" the tiller so the boat can be hand steered.
Chuck, The ST4000T is rated for about twice the displacement of the 27 so I'm hoping I have oversized it enough.

I'm fortunate that the boat was a "wheel" model that no one installed the wheel on. The rudder tube is already opened for a quadrant so I am hoping to capitalize on that. Also the idea of having a wireless remote sounds great but frankly I'm skeptical. The only guarenteed thing about electrical equipment on a boat is that sea water will short it out.

[Alan Wheeler]

Well yeah there is a way to free it. But it means having access to the tiller/pilot ball joint to release it. So you just have to remember that having this below deck means a little more hassle. May or may not be a problem, but you need to think of that. The linear drive is a long threaded shaft that has a stepping motor turning a thread to move the shaft along. So in a stopped mode, there is no physical way you can move it. it must be disconnected.

[Alan Wheeler]

Ooops, now reading your last post further, I am a little confused. So you have a tiller arm directly on the rudder shaft??? But you also have a quadrant below deck, but it is not connected to anything??? is that what the situation is???

[Richhh]

Hi Alan -
With a tiller there is no quadrant.
The linear drive (with clutch clamp) attaches to the aux. tiller.
When the linear drive is off so is the clutch clamp ... with minimal resistance to turn the original tiller.

I have a wheel steering w/ quadrant, a separate attached tiller to the ruddershaft (belowdecks and just above the quadrant) when the AP is 'off' there is very little resistance from the 'unclamped' linear drive. Benefit is if I ever lose the quadrant I can still steer with the AP (or the emergency tiller).

[Alan Wheeler]

Right now I got ya. I was thinking it was a tiller pilot that was being installed. Hence my question just above because I then wasn't sure what was going on. Yep I can see it working fine with a linear motor with clutch.
It's that American accent again twas the problem;-)

[Pura Vida]

Alan, I understand the confusion in terms. Raymarine does list the unit under "Tiller Pilots" but it is more robust than what I normally think of as a tiller pilot. The tiller is connected to the top of the rudder post iin normal fashion and below decks the rudder post is exposed for the addition of a quadrant or an arm for a tiller pilot.

Rich, which AP do you have?

[Richhh]

I have a Raymarine 6000T.

I hate Raymarine as their equipment becomes obsolete faster than Micro$oft products and just like Microsoft once it becomes obsolete they provide no service nor parts. ... but the price was better than competitors. Have had it 3-4 years and am happy with it.

[jstevens]

Pura Vida,
I think only Wheels understood or addressed your question on this thread. As I understand it your have a tiller steered boat with a quadrant installed on the rudder post below decks. You are looking to upgrade your tiller autopilot to the ST4000T and considering putting it below decks.
I had an ST4000T on my previous sailboat and I do no believe it, or any tiller autopilot is a good choice to put below decks. Unless you have immediate access to the drive arm of the pilot and can disdisconnect it from the quadrant. I know of no tiller pilot that has a clutch (like the ST6000) to allow you to remotely disengage it.
My question is, if you have a tiller why do you want to put the autopilot below decks. IMO nothing works better and is easier to operate than an above decks tiller pilot.

John

[Alan Wheeler]

Yeah thanks John, that is why I too am confused on this subject. Are we talking a "tiller pilot" which is a long electricaly driven actuator, or a "linear drive" unit which is basicaly a box with an arm that moves in an arc. The linear drive has a clutch, the tiller does not and is connected to the tiller arm.
Only a linear drive will have the power required to turn the rudder at a quadrant falcrum point. a tiller pilot needs to be mounted further away from the rudder shaft out along the tiller arm.

[Pura Vida]

Thanks John, Again I am usinig the term after reading (or possibly misreading) the Raymarine website. It sounds like the ST4000T is not the right unit for my needs.

I would like to put the autopilot (I'll quit using the term tiller pilot) below decks to improve the installation. In order to clear the cockpit lockers the AP has been set about two inches farther back than the installation documents suggest. No big deal in itself, but the bracket that links the tiller to the Autopilot places the tiller at a bad angle in the cockpit and is not very secure. I want to move it all below decks to get it out of the cockpit entirely.

[jstevens]

Pura Vida,
I understand the desire to get the autopilot out of the cockpit. I'm sure you will find that once you start looking at the price of below-decks autopilot the entry cost is much higher than that of a tiller pilot. IMO it would be a lot more cost effective look at other ways to install the pilot to your tiller. I'm familiar with the C&C 27, but I don't recall the tiller orientation (I think most came with wheels). There are so many mounting options there ought to be one that works well (if not ideal). Most below decks autopilots are designed for boats of more than 15,000# displacement and would be an overkill for the 27 (and draw a lot of current under sail). Even if you could steal one on eBay it still may not be the best answer for your boat.
One nice thing about the ST4000T is that it is powerful enough that with a balanced or partially-balanced rudder is can be connected to the tiller very close to the rudder head.

John