TGweeder Posted May 21, 2019 Report Share Posted May 21, 2019 What are people's thoughts on bolt on anode's ? Currently refitting inside and out. Have removed all the anode's preparing and repainting then refitting the anode's so I have paint under them. My dilemma is and i keep doing it is, I have done some painting on the inside of the boat and will end up burning the paint. Thinking of bolt on I could preempt and just bolt the anode's on when finished. I have seen a boat with bolt ons just wondering if there is any disadvantages. Link to comment Share on other sites More sharing options...
OldGoat Posted May 21, 2019 Report Share Posted May 21, 2019 Quote Initial reaction - most anodes are welded on because:- bolts can shear off causing a leak / flooding poor contact area for bolts (need a low resistance path for an anode to work - similarly the contact area must be metal to metal and NOT pain on one side Link to comment Share on other sites More sharing options...
hider Posted May 21, 2019 Report Share Posted May 21, 2019 I have stainless bolts welded on for one set of anodes, and one end of the second set, other end is welding straight on. One set is older than the other so I only change one at a time. Never torn a bolt off. Would never drill a hole for a bolt. Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted May 21, 2019 Report Share Posted May 21, 2019 (edited) Not having paint/blacking behind welded anodes shouldn't be a problem as they are the best protected bits of hull on the boat! Shielded from contact by the anode. Shielded from corrosion by the very close proximity cathodic protection of the anode. What @hider says. Wouldn't bolt through due to the sinking risk if the bolt failed, but would weld a bolt on, in which case you might as well weld the anode anyway as your paint is already burnt. Jen Edited May 21, 2019 by Jen-in-Wellies Link to comment Share on other sites More sharing options...
cuthound Posted May 21, 2019 Report Share Posted May 21, 2019 My boat was built with bolt on anodes. Two years ago, when the boat was 10 years old, they were due for replacement. The yard where the work was done welded a set of new ones next to the bolt on ones. Link to comment Share on other sites More sharing options...
ditchcrawler Posted May 21, 2019 Report Share Posted May 21, 2019 I have a bolt on anode in the bow thruster tube Link to comment Share on other sites More sharing options...
TGweeder Posted May 21, 2019 Author Report Share Posted May 21, 2019 (edited) Sorry might not of explained very well. I would not be drilling holes for bolts ?. If I choose to bolt on I would weld stainless nuts to the hull and machine stainless bolts to fit. Currently on the bow I have the water tank removed so can still repaint inside so now would be the time. I was thinking for the future ?? If/when they need replacing again I would have to weld again, with bolts on i would not. (Thinking aloud) what happens to those who have spray foam insulation when it comes to this for example ? I am coating the hull with Zinga too so want to get this right. @OldGoat are you saying there should not be any paint behind the anode's or it's okay as long as you have good contact through the welded flats? hope everyone doesn't mind me asking always learning and now's the time for me to get it the best I can for longevity and less work in the future. thanks everyone for your replys ? Edited May 21, 2019 by Tim Gilbert Link to comment Share on other sites More sharing options...
Pie Eater Posted May 21, 2019 Report Share Posted May 21, 2019 Mine are bolted on and I remove them every 2 years to black behind them and renew the anodes when needed. The bolts were welded on 20 years ago when the boat was built. 1 Link to comment Share on other sites More sharing options...
tosher Posted May 21, 2019 Report Share Posted May 21, 2019 Mine have been bolted on for 13 years, no problems at all. Easy to replace with no labour costs. Work just as well as welded on ones. 1 Link to comment Share on other sites More sharing options...
ditchcrawler Posted May 21, 2019 Report Share Posted May 21, 2019 I dont think I would weld stainless nuts onto the steel hull. that is just another dissimilar metal junction, Also I would weld bolts, as nuts limit the length of thread of the bolts and if the next anode is a little bit thinet it may not clamp tightly under the bolt head. Link to comment Share on other sites More sharing options...
TGweeder Posted May 21, 2019 Author Report Share Posted May 21, 2019 1 hour ago, ditchcrawler said: I would weld bolts, as nuts limit the length of thread of the bolts and if the next anode is a little bit thinet it may not clamp tightly under the bolt head. Yep good point. Link to comment Share on other sites More sharing options...
Troyboy Posted May 21, 2019 Report Share Posted May 21, 2019 I've got bolt on anodes on my boat which was built by Peter Nichols in 1981 . It is a simple task to unbolt them every two years when I black the hull and then bolt them back on again . The front ones have what can best be described as a metal fairing welded on to protect the anodes from damage . I've owned the boat 32 years and had no problems. 1 Link to comment Share on other sites More sharing options...
matty40s Posted May 24, 2019 Report Share Posted May 24, 2019 You can make anodes last MUCH longer with this clever trick off a new boat 1.Black boat, inc anode bolt stalks. 2. Fit anodes. 3. Fasten to hull using Nylok nuts. However, to be fair , they have blacked the bowthruster tube!!!! 2 Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted May 24, 2019 Report Share Posted May 24, 2019 On 21/05/2019 at 16:53, Tim Gilbert said: (Thinking aloud) what happens to those who have spray foam insulation when it comes to this for example ? The areas at bow and stern where they are attached aren't usually insulated inside. Anodes part way down the sides, if fitted, could be a problem for the internal insulation and if they were sunk in to steel pockets to protect them, then screw stud mounting would be a good idea. Jen Link to comment Share on other sites More sharing options...
TGweeder Posted May 28, 2019 Author Report Share Posted May 28, 2019 Update. Thought I would share, this is what I have done 16mm stud's ? All inside the width of the boat incase you was concerned ? 1 Link to comment Share on other sites More sharing options...
hider Posted May 28, 2019 Report Share Posted May 28, 2019 Tidy job but bend the tab ends in, they will pick up a load of rubbish otherwise. Link to comment Share on other sites More sharing options...
matty40s Posted May 28, 2019 Report Share Posted May 28, 2019 Good job, and they will be far more effective than the ones I pictured above!! 1 Link to comment Share on other sites More sharing options...
TGweeder Posted May 28, 2019 Author Report Share Posted May 28, 2019 1 minute ago, hider said: Tidy job but bend the tab ends in, they will pick up a load of rubbish otherwise. Ok will do thanks . I did think about putting guides at the ends but it's never ending ? excuse the pund Link to comment Share on other sites More sharing options...
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