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Old 03 April 2005, 16:41   #1
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Country: UK - N Ireland
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Question re Pacific 22

When I first bought my P22 years ago the hydraulic trim rams were trashed by galvanic corrosion within three months of it being on its mooring.There is rather a lot of electrolosis in the water where it was moored.

The boat still went okay but for the fact I could not trim the z drive.

The rams have now been replaced with new ones and I don't want this happening again.I've relocated to a different area and now have a 4x4 and trailer.The boat lays up about a mile from the slipway and I have a swinging mooring in the harbour where I believe there is no residual electricity in the water.

All very well you may think.

My question is,what do other P22 owners do with their boats?
Do you keep them in the water all year round?
If not,how long for?
How long am I best to leave the boat in without risking corrosion?

Any advice would be appreciated.
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Old 03 April 2005, 17:40   #2
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Hi mate, my Pacific lives in the water 8 months a year in a Solent Marina. I have also replaced the rams last year but noticed the S/S screw which holds the top cover on the stern drive lined up with the worst of the corosion, so now leave it off.

It does hack me off when I see domestic 240v extension leads running around the marina and dipping into the water. Never mind that someone might electicute themselves thats my annodes fizzing away. I have also doubled the size of the annodes so they now last about 12 months before requiring replacement @50%.

The rate of corrosion as you point out is going to vary, I kinda hope that the five coats of paint on the stern drive will help keep the amount of exposed metals to a minimum. Also the antifouling on the transom and stern drive is different to that of the hull antifouling which contains copper.

We did discuss this a while back and the need to electrically bond everything together, however I am concenered that what every I use to bond the parts together could end up making things much worse.

I also life her out 3 or 4 times during the year just to check things over, and replace the antifouling (normally in May before the worst of the barnacle attacks begin).

Pete
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Old 04 April 2005, 04:35   #3
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I had the same problem as pete7 with a screw carving a slot in the side of the piston but the real issue with these pistons is that they are virtually isolated from rest of the drive. They are on rubber bushes both ended and the only chance of any bonding comes from the wire gauze on the hoses and even this doesnít really work because the hoses are almost isolated as well What I have been doing is using a couple of jubilee clips around the rams and braided earth strap to connect the rams to the transom unit. But to be fair Iím not really happy with this arrangement and I am thinking about anodes on the rams themselves
As to the your other questions, I keep my boat on a swing mooring for about 6 to 8 months a year and there is no time limit for corrosion if things are wrong it can take a matter of weeks Earth bonding on everything and big anodes are the only way Des
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Old 04 April 2005, 05:38   #4
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Quote:
Originally Posted by Scary Des
But to be fair Iím not really happy with this arrangement and I am thinking about anodes on the rams themselves Des
Des, are you thinking of the ram body or the s/s shaft? would be interested in this as well.

Pete
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Old 04 April 2005, 06:02   #5
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Quote:
Originally Posted by Pete7
Des, are you thinking of the ram body or the s/s shaft? would be interested in this as well.

Pete
Ram bodies Iíve not had a problem with the SS shafts. Iíve had a look at a load of RN service return rams and all seem to suffer from the same problems The valve block at the top of the ram is isolated from the body of the ram and will corrode around where the hoses screw in The body of the ram corrodes where it is screwed into the valve block because the action of screwing it in breaks the paint In fact any excuse these rams can find to corrode is taken up with both hands and exploited Iím looking for an anode that will fit in the limited space and that I can earth to the ram which is harder than it sounds because ideally it should be bolted on, I let you know what I find Des
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Old 04 April 2005, 06:56   #6
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Des, 2 thoughts, one, lots of paint which I did a year ago so much see how its getting on and the other, given the number fo these drives about perhaps MG Duff can help us.

http://www.mgduff.co.uk/index.html

Pete
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Old 04 April 2005, 07:30   #7
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Thanks Pete I did the Ďlots of paintí bit and it failed (I got it wrong) so now itís lots of paint and anodes
I think I have the answer, I spoke to John Latham (http://www.zincsmart.com/index.htm ) and I have order a couple 2Ē shaft anode (CMC-09R) which John will bore out to 2 1/8Ē to fit the rams. I think these will just fit in the space available although they might need a bit of modifying near the hoses. Iíll post some picture when they arrive.
John suggested using battery earth braid to connect the rest of it up and to try and run a connection back to the engine, something I havenít got Des
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Old 04 April 2005, 18:05   #8
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des,sorry for not replying to your post last week, i am working offshore most of the time at present and its not always that easy to get to the pc. i did similar last year with a large anode bored out, it was an exercise on a friends rib and we used a surplus piece of a ships anode which was machined down. i havent mentioned it to him recently, but it will be interesting to see how they work and yours. The material that we used was a magnesium alloy which was seemingly (according to the sales people ) very reactive and ideally suited for items which suffered from excess corrosion . a bit about these magnesium anodes here : http://www.globalcathodic.com/magnesium.html

i suppose we wont know for a few years what difference they make, but for what little they cost to make i am sure that they may be worth it.

The other area on the rams that causes a problem is where the low grade stainless steel hydraulic fittings go through the base. My advise on removing these hoses in a service or whilst painting is - dont!
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Old 04 April 2005, 18:39   #9
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Thanks for the info chaps-have gleaned a hell of a lot of through your experience with P22 matters.
It would appear that the 'Achilles Heel' of the P22 are these hydraulic rams on the sterndrive and at about £600 each, real consideration needs to be given to the length of time of immersion in salt water.
Someone once told me that electrolosis only occurrs when the engines are 'burnin an turnin' but in Strangford Lough my boat was on a swinging mooring within spitting distance of the big red cast iron lightship of Down Cruising Club, if you are familiar.The ion exchange in the water is reputed to be so bad that rising chain only lasts about two-three years-and thats with a 'tear-drop' anode bolted to the chain!
As a knee jerk reaction I put two doughnut anodes on the stern leg on each of the flat surfaces and they were 50% gone within a couple of years-no harm done to the leg though.
As galvanic protection of the rams seems to be a 'grey area' I can ill-afford to replace them again in the near future and hopefully where the P22 is now going to be electrolysis will be negligible.I'll keep it in the water for a couple of weeks at a time in order to get rid of the bug and then lift it out.
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Old 06 April 2005, 19:17   #10
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just something ive remembered, i dont know if anyone is aware that there is a large anode approx 120mm x 60mm x 25mm thick available for the top of the drive (gearbox case) just in front of the lifting eye, it screws in to the two blind threaded holes which are on the top. Have only seen a couple, I will take a photo when i get back and post it.
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