Here's the reply I received from Manson Anchors. Guess I need a can of cold galvanizing spray from Walmart. Go figure.
Hi there Howard.
To clarify some things about galvanisation first. Galvanisation is a
coating, and additionally when applied to the shanks of the Manson Supreme
and Manson Boss needs to be regarded as the softer sacrificial coating that
it is. When galvanising if formed, there is a coating and also a Zinc Alloy
forms with the top layer of the parent/base metal the anchor is constructed
Because high tensile steel is much much harder than it's mild steel
counterpart 250 Brinell Vs 120 Brinell it means that the Zinc top coating
becomes the meat in the sandwich far more than with an old generation
The expectation is that your anchor is quite similar to the paint work on
the front of the car, it's susceptible to stone chips, and impact damage in
exactly the same way. Use the anchor more and it will be at higher risk. Use
it in rocky ground and it will be at higher risk of damage. It really only
takes on anchor episode where it hits some steel debris or a harder rock, or
even stone or boulder on the seafloor to cause damage to the galvanising
We galvanise thousands of anchors ever year. We use the best galvaniser in
New Zealand, and additionally we send hundreds back to be regalvanised from
our QA process which is extremely rigorous.
The seabed is a very tough environment. We have had two Superyacht anchors,
made from Lloyd's Register approved 316L anchor in seabeds where the 316L
corroded. The analysis was conducted on the plate by a leading Metallurgist
in the USA, and it was determined that it was nothing to do with the
material and it's to do with the seabed. 316L corrodes in certain saltwater
This is why Manson cannot offer to warranty galvanising. We simply have no
idea what each anchor hits, is anchored in and the potential for damage is
really high that it's not commercially viable and we'd need to dramatically
increase the price of our product. An anchor could get damaged in one
situation, and then it could take months for the issue to arise. This would
then never be attributed to that incident.
Just as in your car, you have to check the paint on the front for damage and
if it's not mended it will continue to corrode and eventually rust. The
owner of an anchor should be expected to review the galvanising on the
anchor, and, remediate as required. Whilst we do all the QA possible so too
does the customer. When an anchor is purchased, the galvanising is fairly
straight forward to analyse visually. It's a what you see is what you get
scenario, if it looks good, 99.99% of the time it is good. Presumably you
saw nothing remiss when you purchased the product.
So, in relation to your enquiry below. Yes you've watched the anchor come up
100's of times, but have you watched the anchor hit the seabed every time
and been sure that it's not suffered impact damage on the way down, or hit a
piece of concrete or steel on the seafloor, it's impossible to say that it
has not. You yourself admit you've anchored hundreds of times. Heavy use,
means must higher risk of damage and wear on the galvanising coating. To say
on the forum that my email to you was BS is a little insulting as quite
simply it wasn't BS, I never lie to customers. I've seen good galvanising
and bad, and your photos were not due to bad galvanising. There was clearly
impact damage on the anchor.
The solution is firstly to topically spray your anchor, or, and should that
fail, after heavy use over a period of a few years to have the anchor
regalvanised. Chain will do the same thing over heavy use and require
regalvanisation. You as the user cannot have an expectation that the
galvanising will last forever, this is not founded on any principles of
galvanisation if you understand the process and the relationship that using
the metals in the construction of our anchors involve.
This is absolutely not at all related to Rocna building product out of a
material they knew to be below their advertised tensile strength. We have
always been clear with our customers over the last 40 years about the
expectations from galvanising. We would totally refute any inference
The pitting on the shank in that customers' situation on Trawlers forum we
have reviewed, sent to our supplier, and, this is inconsistent with the
problem being to do with the galvanising and likely more an isolated issue
due to the higher phosphorus and silicon levels in the high tensile steel
and nothing can really be done to avoid the very very occasional issues when
they arise. Note the anchor isn't rusting, it's just causing little pits
which can be filled with some topical treatment, as you'd do with stonechips
in your bonnet.
Thanks again Howard for your email, but it's important to inform you of the
real work expectations of high tensile steel galvanising, and, galvanising
itself as a corrosive protectant. It's important we match customer
expectations with the realworld situations and scenarios.