T/P to trimtab

vic008

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Am having major problems getting this to work. OK for 10s then ram fully extends or retracts. Have the T/P set up fore-aft and am wondering does it need to be sitting athwartships?
 

jamie N

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The flux gate compass in the 'arm' is set up to react to a change of heading at right angles to the direction of the 'arm'. I'm slightly confused about how you've got a tillerpilot set up fore/aft as well, unless I've totally misunderstood the query, in which case take pity and ignore me!
 

vic008

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Thanks, you say it does matter. The lever for the trimtab sticks out at a right angle to the fore/aft line. (Like the A/P sort sits on the side deck )
 

TLouth7

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I don't think that the fore-and-aft orientation can be your problem; this will result in the quoted heading being off by 90 degrees, but a given change of heading is the same whichever way round the flux-gate is.

The most likely thing is that you have it backwards. (In conventional use) TPs are generally setup by default to be positioned to Starboard. Thus they expect to push in order to turn to Starboard. If you position such a TP to Port it will push/pull the wrong way. So if the heading is slightly off to Port it will move the tiller to Starboard, increasing the heading error and so moving the tiller further across. Thus the behaviour you are seeing where it rapidly moves to the limit of travel. You should be able to change a value in the TP settings to reverse this, so try that and see if the problem goes away.
 

jamie N

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Another way forward might be to have the T/P electrically connected, but unattached to the trim tab, and move the T/P by hand to check that you get a proportional response from the unit; this might indicate if there's a fault in the T/P.
 
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