Autohelms/anyone got input on merits of hydraulic v screw drive?

[castaway]

Got to face the fact that my old Pinta auto helm is on its final warning. Any replacment for the Halberdier at 36ft and 10tonne has to be pretty substantial, but most of the offerings from Raymarine Silva Simrad B+G etc. appear to to be fairly similar in what thet do (superficially at least). But one thing I cant get much info on is whether I should think about having a hydraulic drive rather than the more usual screw driven liniar drive.

Anyone have any experience of the merits of either?

Thanks Nick

 

[fireball]

The hydraulic ones can have a pressure release valve - so you can't overload the pump and cause failure (I;m sure this was mentioned on here not too long ago)

 

[sailorman]

i have a 6000 with screw ram

its brilliant
7 ton, 37 ft IOR fin keeler rudder like a Barn Door /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
the Raytheon 6000 is in total control /forums/images/graemlins/grin.gif

 

[castaway]

Maybe then you can tell me: A concern that I have is that with a lot of weather helm on, does the system 'lock and hold' the system, or does it require the motor to be running to hold on , say 5 or 10 degree of rudder to maintain a course? The reason that i ask this is that my existing old system lets the rudder slip back to a straight ahead position, and then of course the motor has to cut back in the correct the heading once the boat has started to luff up again.

The reason that it does this is that it only has the 'weight' of the inertia of the motor to hold any rudder offset on......

Thanks Nick

 

[sailorman]

after a few minutes it sets up a "standing helm " ie slight helm if say going to weather (as do all Autohelms).
if you press a 10 deg alteration it re-assesses the helm off-set

apart from a "sticky" clutch 6 1/2 yrs ago ( repaired under warranty)
it has worked without fail since

 

[pvb]

If you don\'t have hydraulic steering...

If you don't have hydraulic steering, there's no real reason why you shouldn't fit an electric linear drive. Mine's an old Autohelm Type 1 with an AH6000 control - it's 16 years old and hasn't missed a beat! Boat is a heavyish 35ft long-keeler.