Autopilot fitting

coopec said:
Are you serious! :unsure:

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

With few exceptions, it is a one size fits all( or to be more specific, 2 or 3 sizes fits all. The link you posted is from a supplier of autopilots and is a bit of a jumble of information. I suspect it's a very old article that's been updated several times, so it isn't entirely accurate any more. For instance, it mentions in the same sentence (in more than one place) drives that haven't been in production for years, if not decades, along with current models. Selection choices for autopilots have changed over the years, most notably with the hydraulic systems.

Better to look on one of the manufacturers websites to see what models are currently being offered. For instance, Garmin:

Marine AutoPilots | Boat Autopilots | Garmin

Note that every single system is based on the same Reactor 40. Lets say the vessel in question is cable steered (as the OPs is), from the autopilot selection page there is only one core pack for cable steering.

Autopilot Compatibility Guide | Garmin Support (also fits all of the mechanical drive systems and one of the hydraulic ones)

Now we need a drive, look at the drive section here and you see a choice of three drives:

Garmin Reactor 40 Mechanical/Retrofit/Solenoid Corepack

1) The Class A Drive Unit works with the GHP 12 Marine Autopilot System to control your sailboat's steering system. This device is designed for use with larger sailboats with up to 28,500 lbs (12,927 kg) of displacement.

2) The Class B Drive Unit works with the GHP 12 Marine Autopilot System to control your sailboat's steering system. This device is designed for use with larger sailboats with up to 79,000 lbs of displacement.

3) The Class B Compact Drive Unit works with the GHP™ 12 marine autopilot system to control your sailboat's steering system. This device is designed for use with sailboats with up to 48,400 lbs of displacement.

Note, no mention of anything other than displacement.

EDIT: Raymarine also only offer three linear drives, selection determined solely by displacement again. Evolution Autopilot Drive Unit Selection | Marine Electronics by Raymarine clcik on "mechanical linear".

Simrad offer a choice of 5 rams, all based on displacement and LOA:

ram-graph.jpg
 
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coopec said:
Are you serious! :unsure:

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

Just to add to the comments on hardware choices which are primarily based on length and displacement plus whether you have tiller or wheel (mechanical or hydraulic) the differences in steering characteristics are dealt with by the electronics. This is where the developments have taken place over the last 30 years or so. In the early days it was more one size fits all, but now when the autopilot is installed and setup the software "learns" the steering characteristics of the boat. The same drive and control software can cope with anything from a lively fast powerboat to a well balanced long keel cruiser and most things in between.

You will discover all this when you get to choose your own autopilot and use it for real.
 
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PaulRainbow said:
With few exceptions, it is a one size fits all( or to be more specific, 2 or 3 sizes fits all. The link you posted is from a supplier of autopilots and is a bit of a jumble of information. I suspect it's a very old article that's been updated several times, so it isn't entirely accurate any more. For instance, it mentions in the same sentence (in more than one place) drives that haven't been in production for years, if not decades, along with current models. Selection choices for autopilots have changed over the years, most notably with the hydraulic systems.

Better to look on one of the manufacturers websites to see what models are currently being offered. For instance, Garmin:

Marine AutoPilots | Boat Autopilots | Garmin

Note that every single system is based on the same Reactor 40. Lets say the vessel in question is cable steered (as the OPs is), from the autopilot selection page there is only one core pack for cable steering.

Autopilot Compatibility Guide | Garmin Support (also fits all of the mechanical drive systems and one of the hydraulic ones)

Now we need a drive, look at the drive section here and you see a choice of three drives:

Garmin Reactor 40 Mechanical/Retrofit/Solenoid Corepack

1) The Class A Drive Unit works with the GHP 12 Marine Autopilot System to control your sailboat's steering system. This device is designed for use with larger sailboats with up to 28,500 lbs (12,927 kg) of displacement.

2) The Class B Drive Unit works with the GHP 12 Marine Autopilot System to control your sailboat's steering system. This device is designed for use with larger sailboats with up to 79,000 lbs of displacement.

3) The Class B Compact Drive Unit works with the GHP™ 12 marine autopilot system to control your sailboat's steering system. This device is designed for use with sailboats with up to 48,400 lbs of displacement.

Note, no mention of anything other than displacement.

EDIT: Raymarine also only offer three linear drives, selection determined solely by displacement again. Evolution Autopilot Drive Unit Selection | Marine Electronics by Raymarine clcik on "mechanical linear".

Simrad offer a choice of 5 rams, all based on displacement and LOA:

ram-graph.jpg
Click to expand...

So you are agreeing with what I said? :unsure: It is not one size fits all?
 
coopec said:
So you are agreeing with what I said? :unsure: It is not one size fits all?
Click to expand...
No he is not - nether am I. The selection is based on the power required which is essentially a function of displacement. If a supplier installer is asking for full details of a boat it is so that a proper choice of type and power of drive is made. How that power is used is determined by the control unit which is largely common and adapts itself to the individual characteristics of the boat once installed. There is no way of inputting type of keel, rudder, rig etc, although there may well be some judgement required on choice of power of the drive when a particular boat is, for example on the margins of the displacement recommendations.
 
coopec said:
So you are agreeing with what I said? :unsure: It is not one size fits all?
Click to expand...

No, i'm pointing out that you were mistaken when you said:

coopec said:
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...
Click to expand...

These days, the only considerations for the drive are displacement and in the case of some, LOA. "long keel/fin keel, balanced rudder/keel mounted rudder, ballast differences..." are no longer factors.

Tranona also makes the valid point about the core packs (electronics). When carrying out the installation there are steps to enter the drive type, vessel type, race/cruise, etc etc. The software then operates differently depending upon the data that's been input. Note that the Garmin autopilots all use the same Reactor 40 heading sensor and the same ACU, it's adapted by the software. Raymarine also use the same headind sensors, but have some slightly different ACUs, notable differences being able to cope with higher current of some of the drives, they still need to be configured similarly to the Garmin systems.

None of the mainstream manufacturers require "long keel/fin keel, balanced rudder/keel mounted rudder, ballast differences..." to be factors.
 
Use our autopilot selection form to determine the best autopilot for your boat

Autopilot Selection Form
By completing the details in this autopilot selection form, our technical sales team will be able to advise on a suitable autopilot system for your boat.





Boat details (required)
PowerSail
Hull Design (required)
MonohullMultihull
Make and Model
Primary use of vessel
Leisure sailingCoastal cruisingOcean cruisingRacingLeisure fishingCommercial
Voltage (required)
Length of boat (required)
Length measurement (required)
MetresFeet
Weight of boat (required)
Weight measurement (required)
KilogramsPounds
Hull Construction
FibreglassSteelWoodAluminium
Steering Stations
One StationTwo StationsOther
Helm turns lock to lock
Steering details
Chain and CablePush / Pull CableDirect Push RodRack and PinionHydraulic SystemTiller
Type of hydraulic system
N/A - see selection aboveManual / Helm pumpPower / Continuos runningPressurised
Cylinder / Ram capacitiy
Join Coursemaster mailing list (New products & specials sent 2-3x/yr)
Yes pleaseNo thanks
Your Name (required)
Your Location (required)
Your Email (required)
Subject
Your Message
Security Question (required)
What is 7+3
 
Yes, the Raymarine ACUs, despite looking similar to the old "brain boxes", are really just motor drivers to bridge from the world of processors and CAN packets into that of heavy electrics moving machinery. All the intelligence is in the same hockey-puck-sized unit as the sensors. This is demonstrated by the fact that, if you have certain steer-by-wire outdrives found on modern powerboats, you don't need an ACU at all. There's a model of pilot core which has two CAN transceivers, one for STng as normal and one for (I think) J1939. You plug it into the engine/outdrive bus and it simply tells it how to move.

For different sized drive motors, they offer a small range of ACUs. I'm not certain (haven't looked in a while) but I think the smallest one may also lack the clutch output needed for a below-decks drive.

Pete
 
prv said:
Yes, the Raymarine ACUs, despite looking similar to the old "brain boxes", are really just motor drivers to bridge from the world of processors and CAN packets into that of heavy electrics moving machinery. All the intelligence is in the same hockey-puck-sized unit as the sensors. This is demonstrated by the fact that, if you have certain steer-by-wire outdrives found on modern powerboats, you don't need an ACU at all. There's a model of pilot core which has two CAN transceivers, one for STng as normal and one for (I think) J1939. You plug it into the engine/outdrive bus and it simply tells it how to move.

For different sized drive motors, they offer a small range of ACUs. I'm not certain (haven't looked in a while) but I think the smallest one may also lack the clutch output needed for a below-decks drive.

Pete
Click to expand...

That's correct Pete. Good summary of the ACUs.
 
coopec said:
Use our autopilot selection form to determine the best autopilot for your boat

Autopilot Selection Form
By completing the details in this autopilot selection form, our technical sales team will be able to advise on a suitable autopilot system for your boat.





Boat details (required)
PowerSail
Hull Design (required)
MonohullMultihull
Make and Model
Primary use of vessel
Leisure sailingCoastal cruisingOcean cruisingRacingLeisure fishingCommercial
Voltage (required)
Length of boat (required)
Length measurement (required)
MetresFeet
Weight of boat (required)
Weight measurement (required)
KilogramsPounds
Hull Construction
FibreglassSteelWoodAluminium
Steering Stations
One StationTwo StationsOther
Helm turns lock to lock
Steering details
Chain and CablePush / Pull CableDirect Push RodRack and PinionHydraulic SystemTiller
Type of hydraulic system
N/A - see selection aboveManual / Helm pumpPower / Continuos runningPressurised
Cylinder / Ram capacitiy
Join Coursemaster mailing list (New products & specials sent 2-3x/yr)
Yes pleaseNo thanks
Your Name (required)
Your Location (required)
Your Email (required)
Subject
Your Message
Security Question (required)
What is 7+3
Click to expand...
As you see the only "required" of any consequence is lenght/ displacement. The boat type merely required to select the TYPE of drive - Power boats generally use different types of drive, as do multihulls compared with monohulls. All the other stuff is also related to types of drive NOT to power of drive or the control head, which is the same for all. Nothing about what you said in posts#4&7
 
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coopec said:
Use our autopilot selection form to determine the best autopilot for your boat

Autopilot Selection Form
By completing the details in this autopilot selection form, our technical sales team will be able to advise on a suitable autopilot system for your boat.





Boat details (required)
PowerSail
Hull Design (required)
MonohullMultihull
Make and Model
Primary use of vessel
Leisure sailingCoastal cruisingOcean cruisingRacingLeisure fishingCommercial
Voltage (required)
Length of boat (required)
Length measurement (required)
MetresFeet
Weight of boat (required)
Weight measurement (required)
KilogramsPounds
Hull Construction
FibreglassSteelWoodAluminium
Steering Stations
One StationTwo StationsOther
Helm turns lock to lock
Steering details
Chain and CablePush / Pull CableDirect Push RodRack and PinionHydraulic SystemTiller
Type of hydraulic system
N/A - see selection aboveManual / Helm pumpPower / Continuos runningPressurised
Cylinder / Ram capacitiy
Join Coursemaster mailing list (New products & specials sent 2-3x/yr)
Yes pleaseNo thanks
Your Name (required)
Your Location (required)
Your Email (required)
Subject
Your Message
Security Question (required)
What is 7+3
Click to expand...

One form, from one supplier, the information on which largely does not fit in with the choices available from the Worlds leading manufacturers of autopilot.

I's also somewhat interesting to note that after asking all of those question, they only offer two choices of linear drive.

Coursemaster Steering Drives for Coursemaster Autopilots
 
When I last fitted an autopilot to a boat with a Jefa rudder and steering, Jefa advised me that the drive arm should be electically isolated from the steering system and that Raymarine rams, unlike theirs, were not. I overcame this using a chunky Tufnol arm in the linkage. Since I have never heard it mentioned since, was it just sales chat?
 
They have a thing about galvanic action between the stainless steel and aluminium mix in most steering systems. However none of the mix in most systems is actually in seawater so this isolation is perhaps more backside covering than anything else - and good sales chat "ours is different" gives them something to talk about when their product does much the same as others . There is a section on their website on the subject.
 
Quandary said:
When I last fitted an autopilot to a boat with a Jefa rudder and steering, Jefa advised me that the drive arm should be electically isolated from the steering system and that Raymarine rams, unlike theirs, were not. I overcame this using a chunky Tufnol arm in the linkage. Since I have never heard it mentioned since, was it just sales chat?
Click to expand...

Not sales chat, it's good advice. If the drive allows the battery negative to be connected to the rudder, then electrolytic corrosion of the rudder post could occur, depending on material, if the prop shaft is also connected to battery negative. There are some scary photos of the results on this page - Electrolysis – Jefa Rudder
 
On the other hand, the same design of Raymarine linear drive has been in very wide use for thirty years or more, and I've never heard anyone complain of corrosion issues caused by it.

I don't know if there's any continuity from either of the motor cables (it doesn't really have a positive or negative since it turns both ways) to the case. I suspect not, as anything connecting one would be likely to connect the other, and then you'd have a short. But if one of them did, would there then be a connection onwards to the battery negative through the ACU or S-series brain box? Again I don't know for sure, but since it's a reversible solid-state motor drive rather than some simple wiring to the battery via a relay or two, I suspect not.

Pete
 
prv said:
On the other hand, the same design of Raymarine linear drive has been in very wide use for thirty years or more, and I've never heard anyone complain of corrosion issues caused by it.

I don't know if there's any continuity from either of the motor cables (it doesn't really have a positive or negative since it turns both ways) to the case. I suspect not, as anything connecting one would be likely to connect the other, and then you'd have a short. But if one of them did, would there then be a connection onwards to the battery negative through the ACU or S-series brain box? Again I don't know for sure, but since it's a reversible solid-state motor drive rather than some simple wiring to the battery via a relay or two, I suspect not.
Click to expand...

Presumably the clutch circuit is only switched on the positive? So the negative would be permanently connected?
 
I have not followed the links so may have missed this
However, When I spoke to one supplier about how useless my AV100 tiller steered system was on my 31 ft yacht 4.8 ton displacement he asked how big my rudder was. When I told him, he said that was probably the problem. He said that on commercial systems ( he was not the salesman for private yachts, but was just chatting) one of the early things he would ask, would be rudder area & balance.
If one thinks about it, some yachts have very small rudders & can respond quite easily. Others, like mine, have a spade that goes the full depth of the keel, less 50mm. I never broach, unless under autopilot & the autopilot cannot hold any sort of course. My Aeries often does a better job. In fact my backup ST 2000 actually keeps a better course, so all that b..x about learning the yacht, does not wash with me.
But anyway apart from my rant about the useless AV100 I wonder is anyone else has been asked about rudder dimensions.
 
pvb said:
Presumably the clutch circuit is only switched on the positive? So the negative would be permanently connected?
Click to expand...

Perhaps, but the clutch wiring isn’t connected to the drive case. It’s just a plastic-wrapped coil with the two ends passed out of the case through a grommet.

Pete
 
No. I can only speak for the Raymarine linear ones which I’ve had apart, and which (according to Quandary) Jefa are implying will make your rudder go rusty and fall off.

Pete
 
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