Fitting an Autopilot

Frontier

Frontier

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I have begun to think an autopilot would be nice. Looking at the adverts it’s hard to see what you need. They talk about heads and pumps and gyros etc. Why don’t they just sell a box with everything you need in it. This is where you will tell me they do, but I have another reason for the post. My boat needs to be constantly corrected, it won’t just go straight. I guess that’s normal, but I was wondering if it can make too much work for the bit of an autopilot that does the steering?

The poor steering is worse under 6 kts, hence my desire to pass yachts only doing 5 kts up the channel. I know some get annoyed because they think you are a typical in-a-hurry power boater, but at 6kts plus things smooth out and make steering much easier.

D
 
Auto helm ST6000 or better. Brilliant, had it seven years. Had it fitted just after buying the boat after getting fed up of waiting for stuff then just passing it on to the next owner.

Not easy to fit DIY as as my bloke found, all boats are different. It's about getting the hydraulics and rams in the right place, even though some folks may understand the conputer wizzy stuff.

My auto pilot will take me up any river, in fact my steering went at Stourport way up the Severn. I got it mended at Swansea. Not sure why, hardly ever used a stearing wheel since. Got fed up with the boat before, watching the GPS and trying to follow flight plan, oat would hit on wave and change direction, the the next another. I just became part of the robotics. Now I tel the boat to go to err. Guernsey say. It's there on the button and in a straight line. Beauty of auto pilot on a river, theres not all this stear then correct, just guess 30 deg this way or that, bleep bleep bleep, boat comes round instantlyand stays on that course. Can even do it dodging mooring buoys or lobster pots. I'm on shafts with weedy rudders. not sure about outdrives. /forums/images/graemlins/confused.gif
 
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My boat needs to be constantly corrected, it won’t just go straight. I guess that’s normal

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I wait to be corrected from those with wider experience, but it can't be 'normal' - there will be elements which can be improved, others you'll have to live with.

Firstly, there's the speed thing: that's to do with MoBo's having small rudders and relying on prop wash to steer. It also depends on the underwater profile of the hull. So 6 knots may be 'better' than 3 for control, but aren't there other factors? Like the play in various parts of the system. Have you minimised that? It means replacing bolts, worn cables, taking up slack - and if you end up with the wheel moving one eighth of a turn before the rudder(s) twitch, then accept that but no more.

Will the autopilot then add its own errors with delays in time and amount of response? Can you refine these or do you have a bog-standard model? It's very disheartening to replace every nut and bolt to find your pilot has a 10-degree bandwidth!
Oh, and something often overlooked until too late, can you mount the sensor somewhere free from deviation?

My old boat skids all over the place in a following sea; it's hard work even for me anticipating every twist and turn, so the autopilot, which cannot anticipate, works its socks off - but if there's plenty of room and nothing in the way, then I let it get on with the job, and in calm water can thread in and out of moorings with no probs.

Mine's an Autohelm 3000 with belt drive to a teleflex cable control - no hydraulics, very basic, but I wouldn't be without it.
 
Hlb doesn't exagerate about the performance of his autopilot, does exactly as he says, very impressive bit of kit. Whereas mine on the otherhand is a Vetus hydraulic autopilot which is pretty crap, wanders all over the place, even in flat calm conditions. Still I guess it's better than nothing particularly as i spend a fair bit of time at sea single handed.
 
I fitted an Autohelm ST6000 some years ago and as far as I remember, everything came in one box. I fitted that, a plotter, GPS and radar at the same time, all different makes, with no problems.

Straightforward to set up and worked well.
 
We need a bit more info on your boat, is it sterndrives, or shafts and do you have cable steering or hydraulic, and if so does it have servo assistance. The reason it doesn't come in one box is because there are so many permutations. If you have hydraulic steering then you are half way there, you just need the correct pump to connect into the system, and the electronics St6002. If you have cable steering then the ST6002 has lots of options to fit your particular motor installation, pump and cylinder or linear actuator depending on vessel length and displacement.
As others have said once you have had an Auto pilot there is no going back, if they are set up correctly they make life very simple, after I had done an install and calibrated it I used to motor right up through the marina and almost to the quay on the AP just for the fun of it.
Your boat suffers from waywardness which is typical of many planing or semi- displacement craft, as there isn't enough keel to keep it straight at low speed, and its not until you get to about 5-8 knts that the rudder authority begins to take over.
The AP won't completely eliminate this problem, it will just work hard trying to cancel it out.
 
All boats need constant correcting to go straight. Even those that are very directionally stable wander around due to wave action.

Stern drive planing hulls are probably about the worst for some reason.

The main thing to remember is that you don't have to constantly correct it, let it wander around the general course you are heading in, and correct it every few seconds if you are in close quarters situations.

When you get your autopilot fitted you will find there is a damping setting. If you set this too sensetive you will over-work it as it tries to iron out every single deviation. As when manual helming, let it deviate around the general course. You will probably find there is a different setting for slow-speed accuracy, high speed in flat water and high speed in different sea conditions. Quartering seas cause the most work.

Speak to your supplier about the slow speed control issue, they will help you spec. the system to sense this accurately and deal with it in the best way.
 
The only times mine goes tits up, is if following a gps course with a sharp turn in it, then it over corects and weaves about wildly for a bit, think this can be tuned out of it, but it's not that big a problem if you know it's going to happen. Always have it on responce 3, one and two being to twitchy.

I might use the wheel half a dozen times a year, other than that it's auto till the marina then engines only.
 
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If you have cable steering then the ST6002 has lots of options to fit your particular motor installation

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What sort of options are these? If it's anything like mine, the cables directly drive the rudders, no motors. I would like a 6000 series autopilot but it would probably mean changing the steering to hydraulic...

S.
 
In the Raymarine brochure I have the 6000 is no longer listed, its been 6001 for some years and now then 6002, if you have rudders with cable steering then theorectically you can use the M81130 (or M81131 if its under 15 tons) linear actuator which is suitable for boats up to 10 tons, this will have to be mounted so that it can connect to one of the rudder quadrants much the same as a sailboat installation. I imagine that you have some kind of tie bar connecting the two rudders.I would recommend you buy the Gyro compass also as it will give better course holding in rough weather.
 
I didn't know you could get that. Yes, there is a tie bar between the rudders (my current autopilot is a belt driven to helm wheel 3000 model that will only keep you on a straight-ish line - better than nothing though).

I will have to look into this...

Thanks
Steve
 
[ QUOTE ]
my current autopilot is a belt driven to helm wheel 3000 model that will only keep you on a straight-ish line - better than nothing though

[/ QUOTE ] for those of us with nothing this sounds excellent!

with a single (BIII) outdrive on a cable driven PS installation I have always assumed it would (1) be the solution for me but (2) be working really really hard at the slower speeds with my planning hull.

oh well........guess I will continue to live without it a bit longer!
 
Just looked at the raymarine site. Sure enough there is a M81131!

Anyone the difference between the 6/7/8k control heads?

S.
 
The 7 and 8 just have extra functions which are more than you will need, the gyro compass has a gyro to stabilise it so its less affected by boat pitching and rolling.
 
You bet if you are doing 20 knots and its a bit rough, Mobos go over the surface whereas sailboats tend to go through the water and are more stable when sailing.
 
If I was going 20 knots I'd be checking to see if someone had fitted 500hp engines when I wasn't looking! I'd be really chuffed to go 20 knots /forums/images/graemlins/ooo.gif (rough or not /forums/images/graemlins/smile.gif )

S.
 
The boat has a 32ft planig hull, the spec says deep v but its more of a shallow v really. It has sterndrives and hydraulic power assisted steering.

From all the replies it sounds like I would benefit from AP.

Thanks for the advice

D
 
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