Adding external Gyro to Type 100 Autohelm

typhoonNige

typhoonNige

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Prompted by a recent post, I am considering adding an external gyro to our Raymarine Type 100 course computer. Has anyone here tried this? Was it worthwhile? From what I have read so far it seems that it will improve the course keeping on the most sensitive autopilot setting only (3), and the amount of rudder activity on this setting means we never currently use it.

Thanks in advance
 
Have you fitted a rudder reference unit?
I managed to fit one to my tiller steered boat and the autopilot will steer on all points now. Though I don't have your model autopilot.
 
The system is all Raymarine with a 7002 control head, rudder reference, fluxgate compass and direct drive via linear motor to a quadrant on the rudder stock. It's interfaced into the seatalk system so can be used to steer to wind angle or heading. It all works fine but I understand performance downwind can be improved by adding an external gyro. Have found a cheap source of one hence my post!
 
typhoonNige said:
The system is all Raymarine with a 7002 control head, rudder reference, fluxgate compass and direct drive via linear motor to a quadrant on the rudder stock. It's interfaced into the seatalk system so can be used to steer to wind angle or heading. It all works fine but I understand performance downwind can be improved by adding an external gyro. Have found a cheap source of one hence my post!
Click to expand...
They used to (many yrs ago) recommend the furuno gyro. the response will be much faster. I have the fluxgate & that has been very good these past 15 yrs
 
I have a type 300 course computer, I guess fairly similar to the 100.

A few years ago I made myself a gyro rate sensor, using instructions from the internet. It is simply an acceleration measuring pcb which I think was made for robots (?), it need 5v so I added a 7805 regulator, it outputs a variable signal around 2.5v; then three wires out to the "gyro" input of the course computer (seatalk +, rate, seatalk ground).


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Only precaution, as the pcb measured accelerations the opposite way to the pilot needs, the pcb had to be mounted upside down, no big deal.
After mounting it, all calibration, Autolearn etc etc has to be done again.
As you said, it only works with sensitivity at level 3.
The improvement in boat handling capacities is very good with a following sea, the pilot reacts with the anticipation of a good helmsman. I was told this type of setup did not provide the stabilising info for radars, etc, just for the pilot.
However, current consumption gets very high, that is the reason I stopped using it; it is always connected but I just use sensitivity 1, which disables the gyro input. On longer runs I use a wind vane.
The cost of everything was about £30-40, no big loss..
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On another forum, several other people have bought a ready-made gyro sensor, supposedly a replacement copy of the Raymarine one, but though it worked satisfactorily as a gyro sensor, it markedly slowed down the pilot reaction to the fluxgate compass input. Namely, when asking the pilot to tack, the boat wandered all over the place. A few techies posters have developed another version which should take care of all that, and built a few prototypes which seem to be working well. I bought one and will try it next spring, if it uses less power than mine ok, otherwise I'll keep it switched off. These new sensors are not for sale nor they will be, so no business involved.
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So, from personal experience: the gyro sensor definitely increases the boat handling capacities of the pilot, esp in following seas. It also markedly increases current consumption, which may or may not be a concern to other users. If one plans to use it 24/24 for days (say an Atlantic crossing) then suitable charging means should be carefully devised.
Someone else found a negative influence on the fluxgate reponse from some not-OEM ready-made gyro sensors bought on the internet.
 
Thanks for such a detailed reply Roberto. My question answered. I suspected that the increase in power consumption on sensitivity 3 would be a deal breaker, but it's good to have it confirmed by one who's been there already. Also thanks for the info on gyro sensors bought on the internet - probably the same ones I was looking at.

Time to buy that wind vane setup!
 
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