It seems there's interest in the lifting keel system on the Parkers 325/335, in particular at both ends - the sensor end in the keel box, and the display/control panel mounted at the helm position.

I'm willing to share my experience of trouble shooting and replacing parts - would others like to contribute under this Forum topic. We may be able to have enough information to make up a guide on the issue. I'd like to know your thoughts.

I found that the position of my lifting keel was not being correctly displayed. The problem appeared to be within the box that the cord from the keel to inside the cabin void runs over.

As far as I can tell, the "system" is made up of

1) The cord which runs from the top of the lifting keel, over a pulley wheel on the side of a box, and into the depths of the cabin. This cord is kept under tension as the keel moves and rotates the pulley wheel. I don't know if there's a weight at the other end, or a piece of elastic.

2) The box (the keel sensor box) with the pulley wheel attached. Inside the box is a standard off the shelf rotary potentiometer, from which wires run off into the depths of aforesaid cabin. There is nothing special about the box, except it has to fit the housing it sits on.

3) The wiring system which runs from the keel sensor box all the way to the helm position controls/indicators - by which route I know not.

4) The helm keel position control and indicator panel. There is piece of equipment made by DataTek which, presumably, converts the voltage from the potentiometer in the keel sensor box to the LEDs.

5) There also up/down buttons on the panel, which are subject to wear and tear - the rubber boots, and the contacts themselves.

6) Wiring runs from the keel position control and indicator panel, route unknown (to me) to the fore cabin.

7) Under the starboard side bunk in the fore cabin is the electric motor and valves which make up the electro-hydraulic system which raises and lifts the keel.

And then of course there the lift keel system itself - Hoses, rams, etc, but that's been fully covered in other posts ...!

I'm working my way through only 1) and 2), and will report back on how I repair/replace/source the components. The pulley wheel axle is firmly attached to the old potentiometer ...

So far I've purchased the replacement potentiometer (straight forward) and may need to buy another pulley wheel, as the axle of the defunct pot is still firmly attached.

There are still 20 brand new bare PCB's for the head unit available - I'll ask where these sit within the system, and what they actually comprise.

The disadvantage I've heard is that they don't always drive the LEDs from top to bottom, so there is presumably a correct potentiometer to go with the appropriate change in length of the cable from fully up to fully down.

If anyone has tried these modern systems and got them to drive the LEDs from fully up to fully down please share.

Others have found more modern electrical systems, still potentiometers as far as I can tell, that fit directly to the keel sensor box. The advantage being there isn't a piece of string that disappears into the boat!

The disadvantage I've heard is that they don't always drive the LEDs from top to bottom, so there is presumably a correct potentiometer to go with the appropriate change in length of the cable from fully up to fully down.

If anyone has tried these modern systems and got them to drive the LEDs from fully up to fully down please share.

I think you refer to a string potentiometer? That was an option I had in mind, but I think it is a good idea to see what mr Datatek has to offer as a solution.

My potentiometer still works, only the off set has to be adjusted. Besides the LED’s which are barely visible in bright day light. So the indicator box seems to be the primary piece of hardware to replace.

I developed a keel indicator system based on a Wema tank gauge sender and a Wema display after giving up repairing the original offering.

I am pleased to say that it has worked fine for the past 10 years.

Somewhere on the website is the article I wrote for the newsletter and I think I have posted details on the forum in the past. I can re-post them if that is helpful.

BTW - the string attached to the keel is kept under tension by a piece of shock cord running under the trim on the back of the keel box, it tends to perish with time and silicone surgical tubing lasts better.

Martin

335/50 Tringa

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