Hydrovane judder

giraffehappy

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Just fitted a (very expensive) hydrovane. Found that with the hydrovane paddle free it interfered with the steering, under power and sail, and with the paddle locked it was ok-ish under sail, and juddered like hell under motor, with the prop backwash. The vibration was so bad that the back stay was moving... Any suggestions?
 

snowleopard

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I had a similar problem at the end of last season - the bolts holding the hydraulic ram of my steering worked loose allowing the (spade) rudder to flap a little. at certain revs under motor it set up a heavy vibration that I thought was an expensive engine problem.

It's the eddies in the prop wash that make the rudder vibrate and that vibration transmits itself through the boat. Locking the blade ought to stop it, as long as it really is locked, not just restricted. The interference with the main steering sounds as though the wash from the main rudder is hitting the balance area of the Hydrovane rudder and turning it the opposite way to the helm.

Ultimately, both problems are linked to the closeness of the hydrovane to the prop & rudder but there's nothing you can do about the configuration of the boat. I suggest you tell the manufacturers about the problem and if they don't fix it, say it's "not fit for the purpose" and demand your money back.
 

giraffehappy

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Hi Snowleopard and Eloise,
Thanx for your advice, will try it again and if as bad will probably have to get it taken off as you suggest.
Moving aboard next week..........!!
 

cp99

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Firstly, this is a local problem and not a Hydrovane fault. A solution needs to be found on your boat – the Hydrovane is perfectly fit for the purpose – they steer 18-ton boats faultlessly on circumnavigations, which is more than can be said for Aries / Monitor / Windpilot units, which are perhaps more popular. I have never heard of a boat that did not steer well with one, though of course such a boat must exist.

1. Are you sure that the Hyd. driveshaft is fitted absolutely vertical, and in line with the main rudder?
2. The vibration under engine: does it occur only with the Hyd. locked in neutral, or also if the unit is left in gear, but with the windvane removed?
3. Is the vibration on the rudder, or in the gearbox unit (or both)?
4. If you fit a tiller arm extension, for a tillerpilot, then lock this over slightly off centre when motoring – does this fix it?
5. Can you have a remote Hydrovane rudder attachment tool made (these are custom items not available from Hyd.), and remove the rudder when motoring?
6. If the vibration is rudder 'flutter', then one solution is a small block fitted on one side to disrupt the flow. This should not wreck the flow totally since it may in any case be faulty, or at least wrong for your boat.
7. Ask for a replacement rudder, preferably one of the next size down.
8. Tie a line to the handle of the water paddle and lock it off to the side, against the gearbox lock pin, when motoring.

And there are almost certainly other avenues to explore. Don't give up on the Hyd., since you are unlikely to find a better windvane. I don't have any connection with Hyd., but mine has worked faultlessly on 5 to 11 ton boats, and as an engineer I recognise something that does the job superbly well; I've lost count of the number of owners who have moaned to me about their servo-pendulum gears.
 
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