Autopilot fitting

[mrangry]

I am about to purchase a below deck autopilot system to connect to my n2k network. I have decided on the Simrad nac 3 system as I already have b&g plotter and triton screens. I have still to decide on which linear drive.

The boat is a Beneteau Oceanis 440 with wheel steering. At the back of the wheel there is a cog engaging on a length of chain which has steel cable attached to either end, these cables pass through blocks and terminate on the rudder quadrant.

This issue I have is, should I connect the drive unit directly to the quadrant which has an existing hole dead ahead position, or should I have a steering arm fabricated to facilitate connection to the rudder stalk. The rudder stalk is 60mm diameter and appears to be made of fibreglass...would have expected stainless steel.

 

[ithet]

I have a Beneteau 331 and likely a similar quadrant and drive system. I had a Raymarine Linear drive connected to the fitting on the front of the quadrant. This provides a simple and adequate fitting on my boat, but my loads are well below the limits for the drive. Beneteau have used fibreglass rudder tubes on a number of models. If you contact Beneteau (via say Ancasta parts) you can probably be supplied with a diagram of the rudder tube and details of original option autopilot fitting - probably with a part number for a quadrant bracket if you decide you need one.

 

[mrangry]

I have a Beneteau 331 and likely a similar quadrant and drive system. I had a Raymarine Linear drive connected to the fitting on the front of the quadrant. This provides a simple and adequate fitting on my boat, but my loads are well below the limits for the drive. Beneteau have used fibreglass rudder tubes on a number of models. If you contact Beneteau (via say Ancasta parts) you can probably be supplied with a diagram of the rudder tube and details of original option autopilot fitting - probably with a part number for a quadrant bracket if you decide you need one.

Thanks. My only concern to fitting directly to the quadrant was that it is a cast alloy and should it break due to forces applied by the actuator my wheel steering would be rendered inoperable. I will drop a line to Ancasta

 

[coopec]

Thanks. My only concern to fitting directly to the quadrant was that it is a cast alloy and should it break due to forces applied by the actuator my wheel steering would be rendered inoperable. I will drop a line to Ancasta

I'd be very much guided by the autopilot manufacturer's instructions as they would take into account the make and model of the yacht.

 

[tjbrace]

We have a Beneteau First 38s5 and its steering gear is the same as described by op. The linear drive, Hypro, connects directly to the quadrant as does the rudder position sensor. Been like that for many years.

 

[LadyInBed]

There is normally an optimum distance specified by the linear drive manufacturer from the rudder stock to the linear drive, does the hole in your quadrant come near to that?

 

[coopec]

We have a Beneteau First 38s5 and its steering gear is the same as described by op. The linear drive, Hypro, connects directly to the quadrant as does the rudder position sensor. Been like that for many years.

I'm not sure that your comment was meant to be a reply to my previous comment but what I was getting at is the underwater shape of a yacht will dictate what sort of autopilot is required- long keel/fin keel, balanced rudder/keel mounted rudder, ballast differences...

 

[mrangry]

I'd be very much guided by the autopilot manufacturer's instructions as they would take into account the make and model of the yacht.

From what I have read instructions are generic and not model specific at all.

 

[mrangry]

There is normally an optimum distance specified by the linear drive manufacturer from the rudder stock to the linear drive, does the hole in your quadrant come near to that?

That is a good point but not one I can find in any of the manufacturers specs

 

[pvb]

I'm not sure that your comment was meant to be a reply to my previous comment but what I was getting at is the underwater shape of a yacht will dictate what sort of autopilot is required- long keel/fin keel, balanced rudder/keel mounted rudder, ballast differences...

Is that true? I've never heard of autopilot manufacturers providing different autopilots for long keel/fin keel boats, for example.

 

[pvb]

From what I have read instructions are generic and not model specific at all.

You're right, autopilot manufacturers don't publish recommendations for specific make/models of yacht.

 

[prv]

If at possible, I'd recommend fitting the pilot drive at the rudder stock rather than the wheel. Ideally on its own tiller rather than the quadrant, though there's probably not much in it. This gives you an instant backup if anything goes wrong with the manual side of the system, like a cable snapping or block disintegrating. Of course you have an emergency tiller, but it takes a lot longer (drifting in circles with the sails banging around, or getting closer to some obstacle...) to rig the tiller than it does to hit "Auto" on the pilot and regain control. Once back under control you can rig the tiller in slow time ready for close manoeuvring when you reach port.

Pete

 

[coopec]

Is that true? I've never heard of autopilot manufacturers providing different autopilots for long keel/fin keel boats, for example.

Are you serious!

When I contacted a manufacturer they wanted to know the specific details of my yacht. It's not one size fits all.

Selecting an Autopilot | West Marine

 

[pvb]

This issue I have is, should I connect the drive unit directly to the quadrant which has an existing hole dead ahead position, or should I have a steering arm fabricated to facilitate connection to the rudder stalk. The rudder stalk is 60mm diameter and appears to be made of fibreglass...would have expected stainless steel.

Whether or not you connect directly to the quadrant, or use a separate steering arm, depends to some degree on the geometry of the drive unit mounting. If you go for a steering arm, I'd suggest you look at off-the-shelf steering arms from Jefa ( Jefa Steering Systems ). These are tough units which are well-proven on thousands of boats. However, I'd first email Jefa and ask about fitting to your GRP shaft, whether it's advisable or not.

Incidentally, the Jefa linear drive (also sold with Garmin badging) is an excellent bit of kit.

 

[pvb]

When I contacted a manufacturer they wanted to know the specific details of my yacht. It's not one size fits all.
Are you serious!

Very serious, autopilots are usually suggested as being suitable for certain lengths of boat, usually with recommendations on maximum displacement.

 

[LadyInBed]

That is a good point but not one I can find in any of the manufacturers specs

From Raymarine ST5000 Plus SailPilot Owner’s Handbook
• The tiller arm radius for the SailPilot should be 250 mm (10 in)
• The drive unit should, ideally, be coupled to the rudder stock via an
independent tiller arm (for example, Edson and Whitlock offer a
standard fitting)

 

[coopec]

Very serious, autopilots are usually suggested as being suitable for certain lengths of boat, usually with recommendations on maximum displacement.

Length of the yacht is just one of the parameters they would look at. (Maybe you should have a look at the link I provided)

 

[pvb]

From Raymarine ST5000 Plus SailPilot Owner’s Handbook
• The tiller arm radius for the SailPilot should be 250 mm (10 in)
• The drive unit should, ideally, be coupled to the rudder stock via an
independent tiller arm (for example, Edson and Whitlock offer a
standard fitting)

250mm is more or less the industry standard.

 

[PaulRainbow]

I'm not sure that your comment was meant to be a reply to my previous comment but what I was getting at is the underwater shape of a yacht will dictate what sort of autopilot is required- long keel/fin keel, balanced rudder/keel mounted rudder, ballast differences...

That's not accurate. If one was installing a hydraulic autopilot some manufacturers will supply different rams depending on the displacement of the vessel and the dimensions of the rudder, with a correspondingly suitable pump. These days, most manufacturers make fewer models of ram/pump and market them for a range of vessels, based solely on displacement.

In the case of the linear drive being discussed in this thread, there will be a choice of about three drives, based solely on the vessel displacement.

 

[pvb]

Length of the yacht is just one of the parameters they would look at. (Maybe you should have a look at the link I provided)

Yes, as I said, length and max displacement are the factors which autopilot manufacturers list in terms of the suitability of their products. I've never seen an autopilot manufacturer stating that long keel/fin keel boats need different autopilots, which is what you posted.

Your link, by the way, is very much "autopilots for dummies" but also only mentions length and displacement.