Autopilots

Wheel, tiller and autopilots
puremajek
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Autopilots

Post by puremajek » Sun May 21, 2006 5:47 pm

I am sourcing any data on autopilots. Any feedback would be appreciated.



Current options include:

> Windvanes,

> Wheel Pilots, and

> Tiller Pilots.



There appears to be no information on windvanes for catamarans.



The most popular appear to be tiller pilots (on cats) and appear to do the job well.



My preference was going to be the wheel unit, but have little feedback from anyone about this type of unit. 'Cruising Helmsman' (May 2006) has a write-up on autopilots in general and does not speak favourably about wheel units. From what I can gather, it revolves around the 'undersize for offshore work' of these units. I was looking at the Raymarine ST4000 MkII which is rated to 8500kg (ours being 4500 - 5000kg).



Any comment welcome.
James
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Smooth Cruiser
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Autopilots

Post by Smooth Cruiser » Mon May 22, 2006 10:06 pm

I can't offer much help on other alternatives - but I do have a Raytheon ST4000+ Tiller Autopilot and find it very good. It appears to be sized well for the boat. It handles all conditions well. As with any autopilot it struggles a little running straight downwind in heavy winds - struggling a bit once the boat starts to surf and yaw on the waves. I generally take over steering in these conditions - although the autopilot seems to actually do allright - never actually allowing the boat to broach - it is smoother with someone anticipating waves though in these conditions.



Otherwise as soon as the anchor is up the autopilot goes on and it tends to stay on till the anchor is down again!! A great piece of gear!

northerncat
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Autopilots

Post by northerncat » Tue May 23, 2006 7:38 am

i was given to understand that the autopilot could be switched to power boat mode to give it faster response times in those conditions with the downside of chewing a bit more power

sean

puremajek
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Location: Brisbane Australia

Autopilots

Post by puremajek » Tue May 23, 2006 10:37 pm

Thanks for all the data, please keep it coming.



From Smooth Cruiser:
As with any autopilot it struggles a little running straight downwind in heavy winds - struggling a bit once the boat starts to surf and yaw on the waves
This appears to be a challenge on most Catamarans. Peter S told what you have stated, almost word-for-word a few days ago. And agree, that hand-steering in these circumstances would be the way to go.

It appears that Raymarine are trying to remedy some of these glitches and according to their website:
http://www.raymarine.com/raymarine/Prod ... ct_id=3686
and the 'ST4000MkII Wheel Pilot', has now been superseded with the 'S1 Wheel Pilot'. The design characteristics of a multihull I don't think allow this issue to be completely resolved.

Sean
autopilot could be switched to power boat mode to give it faster response times in those conditions
With this particular 'Wheel Pilot', I have been unable to locate a 'power-boat-mode' (or similar) in their waffle however, your theory make does make sense. Have you decided on which way you may go?
James
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Smooth Cruiser
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Autopilots

Post by Smooth Cruiser » Fri May 26, 2006 7:31 pm

On the Raytheon it is not as simple as a "Power Boat" mode - but you can adjust the response time and rudder effort through settings that range from 1-5. When I am motoring I turn the response to 1 - light sailing I have the response on 3 and heavy sailing I have the repsonse on 5 and sometimes turn the rudder effort up as well. This changes the performance and improves it's handling significantly - you can see the effect immediately in the straightness of the wake.



I don't think any autopilot will ever overcome the yawing from running downwind in heavy wind and big waves - as the boat surfs in the waves the forces pulling the sheets vary - which exacerbate the movement of the boat further - the only way to smooth things out is to hand steer where you can anticipate the waves before they come and set the boat correcty for them before they actually push the boat.



Having said that, my autopilot does surprisingly well I think - yes the boat yaws and moves but it catches it before the second or third wave in a set and has never actually allowed the boat to broach - even in some pretty heavy stuff.
Last edited by Smooth Cruiser on Wed Aug 02, 2006 4:39 am, edited 1 time in total.

Trevor
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Joined: Fri Jul 28, 2006 10:35 pm

Autopilots

Post by Trevor » Tue Aug 01, 2006 10:51 pm

I have just bought a Raymarine S1 wheel pilot and found it different to the old Mk 11 in that it has a rudder reference arm that needs to be mounted and attached to a quadrant or tiller arm. This is now made difficult as my steps above the tiller arms are now in place. Fortunately I have a hatch in the step to service the tiller arms, but it will still be harder to fit and align properly

The rudder reference is used to help with course keeping and other instruments if you have them.



Trevor

northerncat
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Autopilots

Post by northerncat » Wed Aug 02, 2006 1:53 am

i have left the last step off my cat, i am wondering given the comments that have been made whether i would be better off purchasing a tiller autopilot, as a they are cheaper and b they may be better at the job being directly attache to the tiller arm. i am putting wheel steering in and am also wondering whether it is worthwhile pusuing the idea of morse steering and cables

sean

puremajek
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Autopilots

Post by puremajek » Wed Oct 11, 2006 3:31 am

Trevor



I have decided to go with the Raymarine S1 wheel pilot.
it has a rudder reference arm that needs to be mounted and attached to a quadrant or tiller arm. This is now made difficult as my steps above the tiller arms are now in place
Thank you for bringing this to my attention a few weeks ago. This statement caused me to suss the system out and insert a small platform from a downloaded spec sheet, prior to gluing the step panel down and have since glassed.
I have a hatch in the step to service the tiller arms
I intend doing the same here too. However, regarding the hatch, have you located any good quality hatches for this type of situation. I ask this as I have been looking around and cannot find a unit that will be strong underfoot as well as water-tight given that this will be a well worn walkway with much foot-traffic. Is it your intention to use this access for an emergency tiller of some sort?
James
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zumsel

Autopilots

Post by zumsel » Mon Jul 30, 2007 11:48 pm

Smooth Cruiser wrote:I can't offer much help on other alternatives - but I do have a Raytheon ST4000+ Tiller Autopilot and find it very good. It appears to be sized well for the boat........


Just one question. I hope it doesn't sound to stupid. Never used a Tiller Autopilot before. Have you to engage and disengage the Autopilot Tiller every time you use the Autopilot. And if so, how could that be easily done when you are going with a wheel steering? I'm currently looking at the new Raymarine units and it seems that the Tiller Autopilot uses less power then the Wheel Autopilot.



Cheers,

Jochen

madaz
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Autopilots

Post by madaz » Tue Jul 31, 2007 5:21 am

I was also wondering about a tiller pilot, but was questioning, do they have to be disconnected from the bar everytime they are not used? or can you leave them connected but just turn it off and steer with the wheel?

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