Autopilot Replacement

[Winf]

Hi all

Currently have a Raymarine wheel drive type autopilot that came with the boat. Have already replaced the drive motor once and the unit struggles in anything more than light conditions. Am looking at upgrading and looking for any tips.

Boat details:

36', centre cockpit. Saildata says displacement of 6500kg but have never had any actual confirmation. Wheel helm. Cable steering, good access to the rudder quadrant. Has a wind vane that has never been set up properly, hopefully rectified now though. Does seem to suffer from weather helm but that may just be my lack of experience. 4 x 105Ah house bank.

All systems aboard are Raymarine so for ease of integration would prefer to go that path unless there is a good reason to do otherwise. We are fairly simple sailors. Generally the AP is to follow a simple fixed course under sail but i have used it to follow routes when motoring when all eyes on deck/lookout are needed.

Looking at a linear mechanical drive unit with matching autopilot control unit.

Main question is the sizing. The type 1 drive and autopilot control unit seems to meet our boat sizing but should I go for a larger type 2 drive and ACU? Significant additional cost for 180kg of additional peak thrust and 450Nm of more torque. About double the power consumption.

Any experience with either setup driving similar size boats? Comments generally, advice? Thx in advance.

Winf

[moctrams]

I installed one on my Cape Dory. Works great. Interfaces with my Garmin GPS.

https://rm.factoryoutletstore.com/Ca...20c4763bb3b35a

[Winf]

"Bump"

Main question is the sizing of there linear mechanical drive. The type 1 drive and autopilot control unit seems to meet our boat sizing but should I go for a larger type 2 drive and ACU? Significant additional cost for 180kg of additional peak thrust and 450Nm of more torque. About double the power consumption with type 2 drive

Any experience with either setup driving similar size boats?

Thanks

[Blue Stocking]

Is your pilot the older 4000 which got it's power from the display or the newer model with the ACU 200. A lot still comes down to the boat's underwater shape, and the conditions in which you expect the pilot to control the boat. I have the older model on my Rhodes reliant, 23000 lbs, and it deals with steering up to about 18knts, or a bit more, if I tie in a first reef.

[ctl411]

If you have the EV 100 not the older 4000 type try turning the response down to "cruising". This will help the drive keep cooler. Also if you don't have the rudder reference this helps a ton. They say you don't need it but it stops the "hunting". Balanced sail plan is also needed more specifically helm load. I'm running the EV100 on my 50 ketch as a temporary solution. Been 4 years now it works so upgrade money has gone other places for now.

[Winf]

The existing system is a Smartpilot X5.

Raymarine have advised that this course computer is not capable of driving even the the type 1 linear mechanical drive.

The only salvageable component from the existing system is apparently the p70 pilot controller.

Winf

[Pete7]

In that case you might as well start again. Certainly second hand systems that are working fetch good money on e bay.

Pete

[Frankly]

Raymarine often lies (probably to avoid basterd installs). The output transistor bridge on the X5 is rated at something like 40 amps. Obviously depends on load factor. The unit is rated at 6 amps continuous and will trip offline at about 10 amps by design (calculation not actual measurement). I have been using my X5 to drive a BenMar rotary chain drive for several years and works like a charm. IP 32 is an easy on the helm ship and driving the wheel shaft is the most energy efficient place to couple the AP actuator.

Lot of variables to consider and always fit a rudder position xducer.

[Winf]

Thanks for the responses so far.

Still doing the homework before i have to fork out cash.

Looking in more detail at the Raymarine system specs, the linear mechanical drives (both type 1 and type 2) seem to be limited to +/-35 degrees of rudder movement in the install manual. Says to make sure the steering end stops are reached before the 35 deg is exceeded.

Our rudder quadrant looks more like it will give +/- 45 deg of total movement so to comply with the recommendation I am going to lose some rudder movement. Not really wanting to give up that if possible.

Both the type 1 and 2 short linear drives specify a max stroke of 12" 300mm and show connection to a 10" 250mm tiller arm. The type 2 long linear drive has a stroke of 16" 400mm but show connection to a 14" 355mm tiller arm.

If anyone knows what I am talking about, is there any reason why i couldn't

1. fit the type 1 or type 2 short drive to a lesser radius tiller arm or

2. fit the type 2 long drive to a 10" tiller arm

to increase the amount of available rudder movement?

Im sketching things on bits of paper but not sure if I am thinking about this correctly.

Thanks

Winf

[hoolie]

It's difficult to think of circumstances when the autopilot would need 45deg of rudder. By fitting a shorter arm you will lose some torque on the rudder that might compromise its performance in heavy conditions. Why degrade the steering for something that will hardly ever be needed?

[Winf]

Originally Posted by hoolie

It's difficult to think of circumstances when the autopilot would need 45deg of rudder. By fitting a shorter arm you will lose some torque on the rudder that might compromise its performance in heavy conditions. Why degrade the steering for something that will hardly ever be needed?

Thanks for the response but its not the autopilot operation I'm concerned about - its the manual steering operation when the AP is off. The rudder stops need to engage at +-35 deg to protect the autopilot when I have +-45 deg of movement available.

Winf

[RaymondR]

I used an ST4000 on a heavy steel sloop for about 20 years and found that whilst the head was an excellent piece of gear the wheel drive component was a piece of crap.

After chewing up the delicate little 7mm wide toothed belts for a number of years I found myself in a situation where I was obliged to improvise with an emergency repair using the guts out of a cheap Chinese battery drill to get out of a bind.

The Rube Goldberg arrangement resulting worked so well it lead me down the path of deliberate improvisation and I started fabricating my own wheel drive mechanisms, a number of which were very successful and far superior to the original Raymarine components.

If you don't mind mucking about a bit and experimenting trying out some of the generic 12V linear actuators available might be an option. Or, if you wanted something pretty bullet proof, implementing a hydraulic system using the cylinder from one of the hydraulic wheel drive systems and a 12V hydraulic pump.