Raymarine Autopilot Question

[bliss]

i have a 37 ft Duncanson yacht with an unladen displacement of 7,500 kg and i am looking for an autopilot - i have pretty much settled on a Raymarine package with a type 1 linear drive - the installation of this seems to limit the rudder travel to 70 degrees - 35 in each direction - the boat has a sail drive Volvo diesel and has never been the easiest to manouevre in tight spaces .... i am a bit concerned that limiting the rudder travel will exacerbate this problem ..... might be a dumb question but is there any way around this ????

[MarkJ]

I can't help with an answer at all, thats far to technical for me. But I can tell you we have had the Raymarine 6001 and absolutly love it!!!
It never lets us down.
The max it ever uses is about 10 degrees of rudder angle.

[Pete the Cat]

Are you actually going to use the autopilot in tight places?

[senormechanico]

The length of the arm from the center point of the rudder pivot to the autopilot driver will determine the angle of usage i.e. shorter arm, less torque available to operate the rudder, but more rudder angle available.

[stillbuilding]

I am sure that 35 degrees either way is the limit for pretty much any rudder. Something to do with drag I am sure. Have not seen a boat stops permitting over 35 degrees.

[sigmasailor]

If you disengage the autopilot (as you would while maneuvering in tight spaces) I guess you can use the rudder the way you are used to in manual mode?

[DeepFrz]

I believe you want to put stops in so your rudder travel is limited to 35 degrees (approximately). Your rudder should always hit the stops before the auto pilot drive hits its maximum travel. I'm sure that is spelled out in the auto pilot drive installation instructions.

This guy was able to eke out 40 deg. in each direction. Not sure how it worked out in the end though.
http://www.sailingseadragon.com/AutoPilot.htm

[osirissail]

Originally Posted by DeepFrz

I believe you want to put stops in so your rudder travel is limited to 35 degrees (approximately). Your rudder should always hit the stops before the auto pilot drive hits its maximum travel. . .

That is both wrong and inviting a serious disaster at sea. In a hydraulic rudder system if the autopilot ram can deflect the rudder further than the rudder stops - you would end up either breaking the ram or breaking the rudder stops/rudder itself. Maximum autopilot rudder throw is always set to less than the actual manual rudder travel available.
- - Even in cable/chain rudder systems setting the autopilot to exceed maximum rudder travel will most likely cause the autopilot system to burn out and then you will not have an autopilot anymore.

[DeepFrz]

I didn't mean the maximum "autopilot" setting. I was only talking about the physical rudder stops and the maximum "physical" limit of the autopilot "drive". If you have an argument with that, take it up with the autopilot manufacturers. They virtually all require stops at 30 deg. left and right of center (may be some slight variation but I have not seen it) and they all specify the distance from the center of the rudder shaft to the center of the drive arm.

[bliss]

thanks for your feedback guys - DeepFrz - i have seen the sea dragon stuff as well and was also wondering if that had worked - i certainly appreciated his photos of the installation too as it just helped to me picture it a bit better .... having it set up so you can easily disengage it seems problematic to me .... might be more likely to fail when you really need it and nipping below to engage / disengage it when you are on your own seems less than ideal too .... i am headed down to the boat today to measure the actual angle of travel .... i might be assuming that it is a whole lot more than 35 degrees given the potential travel to each existing stop but i think it would have to be quite a more than that .....

[bliss]

mmm ... the rudder travel is 55 degrees + in each direction so i return to my original concern about loss of manoeuverability ( how do you spell that ? ) by limiting it to 35 degrees .... still i want an autopilot so i can sail the boat single handed

[DeepFrz]

Ah, choices!!!

[bstreep]

I would be concerned about what will happen to Raymarine's product lines, if the purchase by Garmin goes through.

We have a boat full of Raymarine products, and they are not even close to being on my replacement list.

[bliss]

well Bstreep - can you recommend an alternative ?? I have found a Jefa autpilot on the internet which I think is Danish and appears to have more grunt than the Raymarine Linear drive .... does anyone have any experience with this ???

[goboatingnow]

Bliss raymarines. Autopilots are very good sailed across two oceans with them

as to your rudder travel i very much doubt that you get much effectiveness other then a brake beyond 35 degrees.

Thirdly on a hrdraulic system the stops should be reached BEFOrE the ram hits it's ends. Other wise you will damage the ram. The previous poster is wrong the hydraulic unit has pressure releases to protect underruns it has to lots of things could stop the rudder going over. What you don't want happening us the ran being strained beyond it's own internal stops.

You ll have plenty of control with35 degree swings