blueduck33 12:01am, 21 January 2008
I recently acquired an Achilles (Penelope) and have had a good survey. The keel bolts/nuts are very rusted and I would like to replace them, just for peace of mind. While investigating in the area under the nut heads, I found some well rotted ply wood and remnants of GRP. Beneath this there appears to be plaster-of-paris (?... or something similar) filling the cavity formed by the moulded keel stub.

I would really appreciate any advice on whether this type of filling is normal - and how to proceed with geting the studs out. The boat is currently housed under cover in a barn.
Eclipse 1 11 years ago
I had to do this on Eclipse when I first bought her.. got her resting on 6 inch chocks under all 3 keels first. Then tried undoing the keel bolts by using locking nuts to no avail. Ended up locking the nut to the bolt with a spot weld using my trusty mig, and using a big socket and length of scaffold for leverage. To be fair, despite the rust stains on the keel, the bolts were hardly rusted, but I replaced them anyway. Then removed chocks under central keel, and with brute force split the old sikaflex joint and dropped the keel to clean it up. Reassembled using 8 inch overlength studding, and simply wound the keel back up, cutting the ends off with a little grinder. Not that bad a job really, but it proved to me how effective an adhesive like sikaflex could be..... have fun, John
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NormanKlipspringer 11 years ago
Not done this job myself but you may find this reference on Geof's site useful.
achilles24.users.btopenworld.com/keelbolts.htm
Good luck. Tell us how you get on with plenty of pics etc.
Norman
busy home [deleted] 11 years ago
Have a look at my photos of same job. A long tube ^6 sided socket fron halfords may be deep enough , I have some threaded rod spare . It may be difficult to get nuts but SJ ANDREWS Redruth Cwll Have them ...The powder filler sound like the sealer stuff used around the bolts but I dont like the ply glass combo. What no. is your boat ? if the bilge is 12 ins deep its early with out the foam filling (which gets wet) It may sound a daunting job but if you have electric near its not so bad!! good luck!
busy home [deleted] 11 years ago
Can you post some pics before you drop the keel!
It seems to be the nuts that rust more than the bolts.
Tocviria 11 years ago
my bolts are a bit rusty the survey report said that the nuts woud have to be unrusted and coated. which I did. My A840 has 10 one inch bolts. I have read and re-read about Zethar¨change of bolts. Is a big job. Is the only piece of the boat that awaress me. Though 1 bolt could hold the whole keel easily.But to pull out 10 of those scares me. There is a man that works with boats here that says he would do it , but I am not so sure of his ability. Zethar looks great and when he pull them out the bolts were almost as new
Skykomish E29 11 years ago
I think you will find the same thing most on here who have had their keel bolts removed have said that they are like new when drawn, it seems that it is just the exposed heads that suffer. The worry that i have is stripping the thread in the cast keel, that happens and it is all over! so I have just treated mine see photo on site for details.
Tocviria 11 years ago
mine did look like yours but i treated them with 6 coats of International Primer plus 2 coats enamel to the bilge and so far so good after 5 years they just happen to appear pinhead dots of rust in some areas but I will redo in short afetr 5 years is not a big job, though it was big when it was done first time
Skykomish E29 11 years ago
I really need to clean mine up properly and redo them as the job I did last year was meant as a temporary measure, before getting the boat into the water, there were just so many jobs to do and I was running out of time.
Unfortunately there still are lots of jobs that need doing and things get put to one side.
Tocviria 11 years ago
that is true I keep a list. I have spares I bought a year ago and still in their boxes brand new. Nowadays is easier to buy than to do your work. In fact I bought four new spinlocks and are still in their boxes. Sometimes I think the amount of work/time we put into these dear machines but you will never let them go astray I like sailing
Tocviria 11 years ago
chille , what do you think if you use the bolts in mild steel and the nuts and backing plates in Stainless. The stainless is bad when you immerse it in an oxygen deprived place.??Could assure you could always easily open the bolts. Will the stainless come loose easily with the mild steel bolt? It is always the mild steel in contact with water and air that rusts.
rothwell_neil 11 years ago
You should never mix stainless steel and mild steel as the mild steel will sacrificially protect the stainless steel just as an aluminium anode will protect mild steel. Stainless doesn't like low oxygen environments and you may see crevise corrosion between SS nuts, washers and backing plates as well as down threaded bolts. However at the temperatures we see in the UK and even in the med this is not too bad a problem. The carbon steel to carbon steel mix will corrode but as general corrosion inwards. Thus the whole thing will corrode and only weaken the threaded area as and when this is corroded away. This is why they tend to look a lot worse than they actually are and a good clean and good paint is the answer. Mild steel bolt with stainless nuts will corrode away the thread contact area. Not good!
Tocviria 11 years ago
thank you I was just guessing.Is good this Achilles site, we can learn a lot
Skykomish E29 11 years ago
It is really nice having an engineer on here that knows about this complex subject of Electrolytic corrosion.
Presumabley the reasons you give, i.e. stainless / steel mix being a bad thing is why we don't use stainless steel keel bolts into an iron keel.
Tocviria 11 years ago
hello a24aeolus can you tell me if you can see photos of Tocviria A840 in my profile I just put up
rothwell_neil 11 years ago
Looks a beautiful boat and ideal sailing area. i have windsurfed on that part of the coast and whilst not quite Tarifa very good winds.
Tocviria 11 years ago
thanks neil, emily looks greta too nice blue marine
rothwell_neil 11 years ago
Malcolm galvanic corrosion is a wonderful thing, it keeps electricity towers in the air, pipes in the ground and exposed bits of metal intact on your boat on condition that the right bits are connected to the right terminal or metal. The electrolytic series in seawater is magnesium, zinc, aluminium, steel, brass/bronze, tin, copper, stainless steel, nickel, titanium. Couple anything to the left of anything else in that list and it will corrode to protect the other element. Tag weld an aluminium anode to the nut/bolt head and all will be well with the keel bolt and nut, paint and it doesn't matter, paint after welding an anode to it and sleep well for a decade.
Skykomish E29 Posted 11 years ago. Edited by Skykomish E29 (member) 11 years ago
Wait a minute i thought that the anode has to be submerged in the solution to work, if I understand you correctly you are saying that If I attach an anode to my keel bolts in the cabin they will be protected? I know that my outboard one works extremely well as I have to change it twice a year, but that is one of the prices that you pay for being in a marina with all that electricity about.

Tocviria: You need to click on each of your photos and then at the top of the picture you will see an icon "send to group" click on that and then click on Achilles, then your pictures will appear on the group page, but they are very good
Tocviria 11 years ago
thank you aeolus There are some photos I will get more of the area when I can
rothwell_neil 11 years ago
An anode on the inside will protect the keel bolt and nut exposed inside the cabin as and when bilge gets full of water. When it is dry it can't work but there is no corrosion, so the corrosion on the inside is stopped by an anode. If the bolt were exposed on the outside then this would not be protected by the anode on the inside (minor effect if the inside was wet as the potential would change, but marginal). If I could only stop the leaks then I wouldn't need to worry about this!
Skykomish E29 11 years ago
mmm leaks are like rodents to find, very tricky.
You have presumably re sealed ALL deck fittings? I still have a very very minor leak somewhere in the Aft region of the boat rain water gets in the aft lockers, I believe probably the second "inspection" hole (next to bilge pump) is the culprit, but as I route cables through here, the canvas flap cover will have to suffice, infact I on reflection I think that the water is tracking along the cables and probably dripping in the locker.
Having said all this my bilges have remained dry inside the cabin since I repaired the stanchion and sealed the base with epoxy, finished in gelcoat filler.
I do note though that under the quarter berth cushions there is also dampness but I put that down to condensation.
rothwell_neil 11 years ago
I have some decent leaks at present, about 3" in the bottom of the bilge in 4 weeks. Can't test if this deck or keel as presently in a lake. There are drips from the stays which will be fixed next week and after that will have to see.
Tocviria 11 years ago
neil, press the boat hard when it is windy.let the bilge dry and see after a good sail how is the bilge
Skykomish E29 11 years ago
I think that it would be safe to say that if you are collecting this amount of water without using the boat then it is probably coming in from topsides, as there are so many fittings that pass through the hull.
I think that the only sure way is to methodically reseal every item including the push and pulpit brackets, though time consuming not a hard job, and most can be done by slackening off the screws/ bolts prising the fitting off the deck and scraping out the old sealant before injecting new, without physically totally removing everything.
rothwell_neil 11 years ago
More money to Sikaflex then!
busy home [deleted] 11 years ago
Niel the Damp patch under the quarter berth cushions should not be ignored, A leak via winch /jammer /leads area soaks the balsa core which drains down behind the window (makes you think the window is leaking) onto the stringer that runs full length below window (see my pic)then wicks down onto the berth. To chech this drop the head lining and look for a darker area of balsa in the glass fibre .While the lining is down look under the mast /electric through roof fittings again for darker patches in the end grain balsa (which should be straw colour) ....If in doubt drill a 1/2in hole in the inner skin to check .
The spray hood usually keeps this area dry but those lift the dot fittings can weep, They rust the threads Wet balsa can take forever to drain out when encapsulated so make you think condensation..
Skykomish E29 11 years ago
No ron it was me that has the damp patch under the quarter berth cushion, it is under the rear quarter cushion.
As I have the headlining down I have been checking for any potential for leaks, but none found.
busy home [deleted] 11 years ago
Yes ,Sorry. brain dead,
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