For reference and hopefully to save others a good deal of work, here some notes from our experience of servicing the keel system.

P335/50 Tringa is the last but one 335, was launched in 2008 and has sailed in the region of 12000 miles.

Until recently we have renewed the anode on the keel ram annually and cleaned out the silt that collects in the pocket where it lives, but have done nothing else to the keel system. Three weeks ago, at the end of a couple of weeks away the keel refused to lift fully. A certain amount of fiddling and tightening the pressure relief on the hydraulic power pack half a turn, got the keel raising and lowering but it juddered and was clearly not right.

We had the boat lifted out onto her cradle and after failing to identify the cause of the problem decided that we would service the whole keel system.

Things we have learned:-

The buffer on the hull behind the keel is a 100mm square and 20mm thick piece of nylon66.
The forward buffer is a about 50mm x 70mm nylon66. the original piece was 25mm thick but the stainless mount appeared to have been made to fit 30mm thick, so that is what went back
The buffer fittings are bedded in epoxy and held by bolts going into captive nuts bonded into the structure of the hull. The bolts need to be heated to get them out without shearing off. The aft block had to be destroyed to get it out.
Both blocks were in good condition and were only removed because we were looking for a cause of the keel malfunction.

Removing the 18 machine screws that hold the lead wing into the lower end of the stainless steel foil of the keel was surprisingly easy with a standard hex key.

Using the ram the stainless steel foil lifted cleanly away from the lead without any problem.
After removing the ram, the keel foil could be lifted with the purchase attached to the main halyard that we usually use to lift the ram out.
I estimate the foil weighs around 150kg.
Refitting the foil to the lead was also straightforward, needing only the weight of the foil and gentle rocking of the lead with a leaver to get it to settle into place.

With the mast in place and the boom disconnected at the gooseneck, we could lift the foil high enough to inspect the full length of the nylon guide blocks on the keel, they looked as-new and appear to be made of 2omm thick wax-filled nylon6.
Lifting the keel this far requires the removal of the top mounting for the ram.
Due to the angle of the keel box, I am not sure if the keel foil could be lifted clear of the boat with the mast in place.

Having the ram fully serviced by a hydraulic engineer, including replacement of the hose attached to it, cost just over £200.
The hydraulic engineer reported that there was debris inside the end seal which was causing slight leakage and making the movement of the ram much stiffer than it should have been. I imagine that deposits have formed on the rod of the ram whilst the keel is down, which have then been carried up into the seal when the keel was raised.



The lesson that I take from this is that having the ram serviced every 10years or so is a good idea. Also if you have any problems with the raising and lowering of the keel on a 235/335 and the hydraulic power pack seems to be working, then it is probably worth getting ram serviced before looking very hard for other causes of your problem.

The good news is that we now know that the keel system on Tringa appears to be in excellent condition after 15years and the keel now raises and lowers as it should.

Thank you Martin for this very informative and interesting post. You have certainly gone to a lot of effort investigating your keel and I am glad it is now working properly again. I am sure you are right to suggest getting the ram checked over by a hydraulic engineer every 10 years and replacing the bottom hose and connector. I also intend removing the rust and old paint and then repainting and wrapping it in Denso tape every 5 years or so.
What were the condition of the bolts that attached the lead wing to the foil? Is this something you suggest doing or might it be unnecessary? I understand that some Parker 31 owners have done this but their boats are much older.

Mike Baldwin
Shemar

I agree that Denso tape on top of Denso paste is the way to go for protecting the hydraulic cylinder, I have tried various paints over the years with limited success.

Surprisingly the bolts holding the lead into the foil were in perfect condition. They appeared to have been sealed with silicone sealer and I had no hesitation in re-using the same bolts. I would personally leave these bolts alone unless you need to dismantle the keel. The P31 set up is substantially different with the lead wing bolted up from underneath.

The fittings connecting the hydraulic hose to the cylinder had been encapsulated in a thick layer of epoxy, underneath this the fittings were in new condition.

I agree with Mike: thank you for your clear description of the problem encountered and your investigation and actions to solve it. Good to know about the solid liftkeel construction.
This spring I replaced the anode myself (solo) for the first time. The previous owner said it was done 7 years before.
I was amazed to see the cilinder was without any rust, even without Denso tape. This must be the fact I’m mainly sail on inland water and not on corrosive sea water. The anode however was well corrode, so replacement was surely necessary.