harrytom 642 Posted February 24, 2021 Share Posted February 24, 2021 Km do you have new neighbours on the marina?? In panmure a few yrs ago a few of is were chewing through zincs when a new vessel arrived,it had the supposed miracle electric pulse antifoul system,when it departed zincs went back to normal. Coincidental?? Quote Link to post Share on other sites
CarpeDiem 430 Posted February 25, 2021 Share Posted February 25, 2021 2 hours ago, Island Time said: If you have no shore power lead, or are protected with a working galvanic isolator or isolating transformer, and you still have corrosion issues, the problem is on your boat as there is only one connection to the shore (the water), not a circuit. Can you get stray current corrosion from other boats if you're not connected to shore power and don't have a DC system? Or are you saying that if you're not connected to Shore power then any stray current corrosion is due to your DC system. I understood that you had to be either connected to the shore power, and/OR have a faulty DC system... Quote Link to post Share on other sites
Fish 0 Posted February 25, 2021 Share Posted February 25, 2021 I blame Happy Teeth 🤪 Quote Link to post Share on other sites
Island Time 1,235 Posted February 25, 2021 Share Posted February 25, 2021 56 minutes ago, CarpeDiem said: Can you get stray current corrosion from other boats if you're not connected to shore power and don't have a DC system? Or are you saying that if you're not connected to Shore power then any stray current corrosion is due to your DC system. I understood that you had to be either connected to the shore power, and/OR have a faulty DC system... No, because you are not connected to them with a circuit. The only common path is the water. 1 Quote Link to post Share on other sites
Island Time 1,235 Posted February 25, 2021 Share Posted February 25, 2021 2 hours ago, KM... said: The boat is 108 years old, she was perfectly fine in October, not a single thing has been changed on the boat since before then. There has never ever been any item of any form that connects her to Westhaven bar 3 mooring ropes and the water. The 3 mooring ropes are connected to fittings both ends that terminate in wood, it has not changed for at least a decade possibly closer to a century. But Westhaven HAS changed a LOT, all within metres of her, since Oct last year. To suggest the boat has very suddenly decided to change 107 of history at the exact same time the environment she lives in had some very large dramatic changes defies logic. Well, if the boat has no other connection to the dock, the marina is not at fault. The most common issue I find doing corrosion surveys is a bilge pump with failed insulation, standing in bilge water. To say nothing has changed is stretching it a bit. Things corrode, insulation fails, sometimes circuits are left powered on, or switches/circuit breakers fail. Shorts etc happen. All these things are fine until they are not. The easy path is to blame the marina - which almost all owners try to do. Remember than stray current corrosion is really a DC phenomenon - the reason that the AC ground matters is because it is connected to the boat DC. Whatever you think, you can't change physics. If the boat is isolated from the dock electrically, the issue is on the boat. Anyway, don't guess. Use a ref electrode, and measure. It's normally not too hard to find. Quote Link to post Share on other sites
Island Time 1,235 Posted February 25, 2021 Share Posted February 25, 2021 49 minutes ago, KM... said: You not reading properly again IT. Its pretty simple, either the boat has an electrical connection to the dock, or the issue is on board. Please explain where Ive mistaken your post/s... Quote Link to post Share on other sites
Adrianp 120 Posted February 25, 2021 Share Posted February 25, 2021 I'm guessing this 108yo beauty has no electronics whatsoever? What is the damage its showing KM? Quote Link to post Share on other sites
Island Time 1,235 Posted February 25, 2021 Share Posted February 25, 2021 1 hour ago, Adrianp said: I'm guessing this 108yo beauty has no electronics whatsoever? What is the damage its showing KM? So no engine, no nav or any other lights, no battery at all??? Quote Link to post Share on other sites
Island Time 1,235 Posted February 25, 2021 Share Posted February 25, 2021 OK, Yep that is uncommon. How about a bonding system? Metal thru Hulls? I'm thinking that the boat might offer less resistance than the water, and a stray current might by running thru it as part of a circuit.... If the centreboard is pitted, then that's the exit point. There must be an entry point somewhere. Current can't flow without a circuit. So, does the corrosion occur at coating imperfections, and have a dimple in the center - like this; This is an example of AC corrosion - Ive never seen a boat suffer from that, but this is an unusual case. Really requires a corrosion specialist (not me!!) to identify, but it would be good to understand the mechanism once it is found. Most boat issues are DC. Quote Link to post Share on other sites
Fish 0 Posted February 26, 2021 Share Posted February 26, 2021 If the concrete pontoons are through to metal, that is saying something. Are you near that fancy new walkway with the steel piles driven into the corrosive sludge? That walkway would be a genius way to conduct stray currents and secretly sabotage your boat... Quote Link to post Share on other sites
Fish 0 Posted February 27, 2021 Share Posted February 27, 2021 29 minutes ago, KM... said: Do you mean the promenade that cost $21 million dollars and has been held up since new by a $100 acro prop? Yes about 3m from it, about 10m from the acro prop . Yes, thats the one. I'm have no particular knowledge with material corrosion, but I do understand that you don't need oxygen to corrode metals, and burying steel in marine sludge's just doesn't sound flash. Chlorides and sulphates / sulphites can eat away at all sorts of stuff with oxygen. Wouldn't be hard to set up a wee version of a lead acid battery if I didn't know better. I can't describe the specifics, but I do know you have some basic ingredients for a Macgiver style battery if you need one... And if you have a battery, you have some DC current. If the concrete has corroded to bare reho, well, that is telling a big story. Concrete corrosion is driven by chloride ions I believe (may be wrong though). The disassociated form of sodium chloride. Quote Link to post Share on other sites
Fish 0 Posted February 27, 2021 Share Posted February 27, 2021 26 minutes ago, KM... said: Oh gezz, aren't you just a bundle of joy, that sounds scary I do try. Maybe I need your pre race workout regime. I've got to stress I have no specialist knowledge of these things, just a general technical knowledge. If you do want to get Westhaven fully engaged and pro-active, don't mention issues with your boat, they will just zone you out as noise. Bring to their attention the issues with their assets, the concrete pontoon. That all by itself is telling a very load story. As asset owners, I'd expect Punuku will have 2 dozen consultants down there faster than Jacinda can impose level 3, checking out why the life of their asset and potential RoI is dissolving into the water. PS, I know of just the consultant guy to get onto this case, if you need a reference. Quote Link to post Share on other sites
marinheiro 352 Posted February 27, 2021 Share Posted February 27, 2021 49 minutes ago, Fish said: As asset owners, I'd expect Punuku will have 2 dozen consultants down there ...... who will collectively come up with 3 dozen different opinions, all opinions heavily qualified but of course recommending on-going expensive investigations......😄😄 1 Quote Link to post Share on other sites
Island Time 1,235 Posted February 27, 2021 Share Posted February 27, 2021 Got any pics of the new structure KM? Surely they were not stupid enough to have exposed metal in the sludge? This is why wharf piles are timber, or special concrete and prep to ensure the reinforcing is protected from the liquids. Two exposed metal pylons could indeed form a battery, and if your boat is between them, or nearly so, it could be part of a circuit. The boat must have two exposed bits of metal, or something long and conductive. The pitted area is where the current leaves the boat. There must be an entry point, maybe rudder pintles or shaft? I do understand that in some circumstances damp timber can conduct as well, but don't know much about that. Quote Link to post Share on other sites
Fish 0 Posted February 27, 2021 Share Posted February 27, 2021 33 minutes ago, Island Time said: Surely they were not stupid enough to have exposed metal in the sludge? Errr, you've not been to Westhaven lately ay? the whole new promenade is made of a steel structure, with steel piles into what ever is beneath it, a fair bit being seawater and sedimentary sludge's etc. I'm pleased you also question this, as its been bugging me ever since they built it, how you can put steel in sludge and not have a problem. Thought I just didn't know what I was talking about. Some of those posh new houses just across from you IT have steel piles in the reclaimed GH sludge. 15 m deep, went in like a hot knife through butter. All the digger had to do was hold the I beam up, and in it slipped... They are tied into the concrete floor pad for the house. Which all sounds well and good, but you'd never guess how they get an earth spike in for the electrical supply of those houses.... Tied into the reho of the floor slab. Apparently the building code only requires 50 yrs durability for these things, including piles and floor slabs? Quote Link to post Share on other sites
Island Time 1,235 Posted February 28, 2021 Share Posted February 28, 2021 Yep, knew about the ones in GH. Still dumb, imo, but they are not directly in the water. Possibly not quite so dumb. Time will tell. Theoretically, if the steel bits are all connected, they have the same potential, but immersion in anything acidic at multiple points is asking for trouble. Yes, I know two types of metal and acid make a battery, but guess what - the earth wire is copper.... Directly in sea water, which is slightly acidic, is a recipe for disaster. Quote Link to post Share on other sites
Island Time 1,235 Posted February 28, 2021 Share Posted February 28, 2021 2 hours ago, Fish said: Errr, you've not been to Westhaven lately ay? the whole new promenade is made of a steel structure, with steel piles into what ever is beneath it, a fair bit being seawater and sedimentary sludge's etc. I'm pleased you also question this, as its been bugging me ever since they built it, how you can put steel in sludge and not have a problem. Thought I just didn't know what I was talking about. Some of those posh new houses just across from you IT have steel piles in the reclaimed GH sludge. 15 m deep, went in like a hot knife through butter. All the digger had to do was hold the I beam up, and in it slipped... They are tied into the concrete floor pad for the house. Which all sounds well and good, but you'd never guess how they get an earth spike in for the electrical supply of those houses.... Tied into the reho of the floor slab. Apparently the building code only requires 50 yrs durability for these things, including piles and floor slabs? Have been to Westhaven, just busy with work and did not pay much attention to it. Sounds like a right shambles! Quote Link to post Share on other sites
marinheiro 352 Posted March 1, 2021 Share Posted March 1, 2021 5 minutes ago, KM... said: The thing is Panuku wants to knock over Westhaven and it's users as they know it's the hardest one to do that too so once Westhaven et al fall the rest will go quicker than a tax man after your wallet. I am sure you know Panuku does not own Westhaven any more, they are just the managers. It was transferred back to the council in some fishy deal to avoid tax. https://www.stuff.co.nz/auckland/110522994/auckland-council-plans-220m-tax-dodge Quote Link to post Share on other sites
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