Specialists in their marine industry field ... yeah sure!!

[Larks]

I am amazed at some of the ridiculous antics of companies that claim to be specialists in their fields in this industry.

I went to quote on a job today to replace the hull plating on a reasonably sized ally' boat (aluminium/ aluminum) that's been sizzling a bit.

The owner had contracted an antifouling company - specialists in their field!!!! to antifoul his hull. So they went ahead and antifouled it with normal cuprous oxide based antifoul, needless to say that it immediately started eating away his hull.

I don't know how long it took them to realise their mistake but their fix was to sand blast the hull and weld on a patchwork of doubler plates all over the hull.

I don't think the owner has much more recourse on the anti-fouling company because there were a few other problems as well, which otherwise may not have been as drastic as they are now, but the upshot is that the entire hull plating has to be replaced.

I just can't believe that this poor owner has been put in the position that he has by specialists in their field!!!

[varadero]

There are two builders of large aluminium yachts, one in Europe, and one in the US, who anti foul the underwater surfaces of their yachts with copper based antifouls. The process involves a very high quality coating of epoxy paint on the substrate, prior to any antifouling coatings. I have been servicing a few of these boats and have reccomended to their managment that a removal and change of specification would be a good idea, to no avail. Long story shortened is, after in one case, 12 years no problems what so ever. In another,after 6 years one small case of corrosion in the bowthruster reccess, due to this part being primed apart from the hull in general by hand.
We use the "any increace in normal anode wastage rate" as a guide to the effectivness of the epoxy primers.

[Nicholas Scheuer]

I'm not well-informed about antifouling (freshwater sailor) but wouldn't an aluminum hull with an epoxy coating under the cuprous antifouling be put in a state of immediate crisis if the epoxy were scuffed hard on a rock or a reef? The hull would have all that cuprous surface focused on a discreet ding of bare aluminum.

[varadero]

If it was my boat I wouldnt put copper based paints near it either, I recommended a change. But what has surprised me is on these boats in particular I have not seen a problem. I guess if you do it right first time and apply regular maintainance and care the result is good. The new generation of bottom paints for aluminium hulls are performing so well in the last two years I think there is no longer a need for the risk. The vessels I was talking about are 100foot and 120 foot respectivly, I think if they were to scuff hard on a rock or reef the skippers would be looking for a new berth and the boats would be hauled for repair.

[willmarsh3]

It really pays to know exactly what they are doing, IMHO.

I put copper thiocyanate (Biolux) on my steel boat and don't have any problems.

One day in a chandlery I asked the proprietor where the Biolux was in the store. He asked what type of boat. I told him steel. He then proceeded to argue with me that Biolux wasn't necessary but I insisted. My boat is bottom coated with vinylester so there *should not* be any pin holes. However at one point when I had her on the hard she was improperly blocked and the vinylester coating cracked in one spot. I patched it up by hand but I can't be assured of no pinholes there.

The upshot is why take chances with copper oxide antifouling?