Metalizing a boat hull

[Mercury]

Hi, I am new to this forum and must say it is most enlightening to read all of the posts, thank you!

The reason form my writing is that I live in S. California where there is a tremendous push to eliminate traditional anti-foulng paints such as Cuprous Oxides etc. I have heard many a report of alternate materials such as ceramic, Silicone and others but none seem to live up to the task. I am currently in communications with a company who are stating they can spray coat Stainless steel onto a Gel coated boat hull and offer protection for many years (10+), not from growth so much but that the bottom can withstand virtually any amount of aggressive diver cleanings with literally zero bottom damage! If anything they say " The Stainless will just shine more is all"

I would like feedback on this as for me it means I can sail without polluting and fit in with all those trying to escape toxins in the water.

Thanks,

Mercury

[apex1]

I guess that claim is not proven by so far. And if it has any antifouling properties it MUST be toxic, if we like it or not.

[Mercury]

I apologize if I did not make it clear in regards to anti-fouling. The manufacturer and applicator of the material makes no claim as to anti-foul properties of their coating, only that it is a skin of some 7mm of Stainless steel and as such is a surface unlike paint in that it can be cleaned very aggressively via divers with scrubbing equipment or even a zero tip pressure washer at 3,500 psi. The attachment of fouling will not be able to cause damage to the hull of the vessel. I have witnessed the pressure wash and it is everything they claim it to be. My posting was to obtain feedback as to the value of such a coating.

Thanks,

Terry

[apex1]

If anything adds 7mm to the mass of a vessels surface it has a serious stability problem (the vessel) thats nonsense.

[Mercury]

I am not at all sure why anyone would object to a coating of 7 thousandths of an inch. Am I missing something. The average coating thickness for standard anti-foul paint can be much thicker and is often so so as to extend their seasonal life. Was it perhaps that I used the European measurement?

Not meaning to post Nonesense,

Terry

[apex1]

Am I missing something. . Was it perhaps that I used the European measurement?

Not meaning to post Nonesense,

Terry

No, you did mix something up! 7mm was what you said! thats 5/8 inch!

[Mercury]

Hope the measurement now makes more sense 177.8 micron for the Stainless steel coating is OK, yes? By the way it weighs approx. 48 grams per sq foot or 516 grams per sq meter.

[mydauphin]

Who makes/sells this stuff?

[Mercury]

The company is located in Temecula California, they have not yet launched their product but will in one or two weeks I feel. I will be happy to pass on the info as soon as they have given me permission.


Terry

[rugludallur]

Most corrosion resistant metals get their corrosion resistance from an oxide surface layer they form that protects them from further corrosion. This is the case with stainless steel, aluminum, titanium and most other marine metals. All of the aforementioned metals require that the surface be kept clean, if the surface is fouled it will suffer from crevice corrosion and pitting due to oxygen starvation.

Stainless steel comes in many flavors, 400 series can stain from fresh water while 2205/318 (duplex) will resist corrosion even while submerged in saltwater due to increased crevice/pitting resistance.

Copper based alloys (usually copper/nickel) are to the best of my knowledge the only metals which can be used underwater without suffering from fouling, due to the "natural" anti-foiling properties of copper.

The only method I can think of to coat a plastic boat with stainless (without suspending it in resin or paint) would be electroplating, the problem with electroplating is that without "baking" the object in a furnace after plating it will have micro fractures and cracks in the coating.

The newer non toxic antifouling coatings are typically based on some sort of PTFE (teflon) or nano particle surfaces which are so smooth on a microscopic level that they resist the fouling, at this time they are only recommended for vessels that exceed 15 knots at least once every week.

To sum up I'll put it this way, even if I had a boat made entirely of 2205 Duplex steel I would still coat everything below the waterline with antifouling.

Regards
Jarl
http://dallur.com

[bifflefan]

No, you did mix something up! 7mm was what you said! thats 5/8 inch!

Apex1, your grasp of the math system is to say the least nonexistant. 15mm is close to 5/8". 7mm is close to 1/4". If your going to harrass someone at least have your stuff in order.

[Frosty]

I think i will struggle on a little longer with what I can get rather than spray the bottom of the boat with an unknown product that sounds pretty permanent.

Actually the bottom of the boat is not a prob -its shafts rudders and props that are the high maintenance.

[PAR]

Use truck bed liner. It has good anti fouling properties and cleans easily.

[Frosty]

Here we go!!!, antibiotics, toothpaste, antifreeze , felt tip pens, custard ,mustard, and one that does work is red lead mixed with vinegar.

[apex1]

Apex1, your grasp of the math system is to say the least nonexistant. 15mm is close to 5/8". 7mm is close to 1/4". If your going to harrass someone at least have your stuff in order.

Noticed! Even I mixed it up. But did not go to harras him.

[Mercury]

OK!... I thank you for responding to my posts and for considering me as newcomer with obvious math and dyslexic problems... I followed up with the manufacturer and applicator of the Stainless steel bottom coat and here in brief is what they say of their materials.

"Using 316L Stainless steel encased in a polymer hybrid binder we can apply a coating to the bottom of GRP hulled vessels to a coating thickness of approx. 7 mil (178 micron). Purpose is to provide a non-toxic alternative to traditional anti-foul coatings while at the same time offering a very, very slick, long lasting (ten years +) protection. The coating is diver proof so no matter the aggressive method for cleaning, the abrasion resistance is that good. The coating is also non conductive of electricity which we think is a plus in the marine environment"

I am intrigued by this product because everything I have seen as an alternate to toxic coatings fail miserably when under test, cracking or delamination with ceramics, and with silicone's no wear resistance. There have been others but invariably they also fail. 316L is a product which I believe will achieve the goal where others fail.

Thanks again for the input most appreciated.

Terry

[MikeJohns]

So why not just use copper powder in a waterbased epoxy matrix and have the benefit of 10yr + antifouling renewed by scrubbing rather than re-coating. The 316 sounds like a very poor option since it will foul quickly.

one commercial provider :

http://www.coppercoat.com/

But I know of home brew successes too. The trick is to get cheap powdered copper the water based epoxies are produced as concrete floor coatings by outfits like Sika.

[Ad Hoc]

MJ

So long as there is no alumnium about!! :eek:

[Mercury]

So why not just use copper powder in a waterbased epoxy matrix and have the benefit of 10yr + antifouling renewed by scrubbing rather than re-coating. The 316 sounds like a very poor option since it will foul quickly.

one commercial provider :

http://www.coppercoat.com/

But I know of home brew successes too. The trick is to get cheap powdered copper the water based epoxies are produced as concrete floor coatings by outfits like Sika.

Thanks for thoughtful response: You are correct copper would be a good solution and this company supplying the Stainless can perform this as an option, problem being EPA banning of copper in most harbors on the West coast, The Netherlands has already banned copper in their waterways for leisure craft The Sea Grant (tax payer funded) has been seeking alternate coatings for a number of years as places such as San Diego Bay are under pressure to shut down marinas due to extreme levels of cuprous oxide (copper containing paints) some of these measured levels have reached proportion of Super clean-up funding. I have viewed Coppercoat but I am not sure they have EPA approvals for use in the USA?

What experience do you have with the cheap popwder and epoxy, would not the epoxy chalk and breakdown?

Terry

[apex1]

Epoxy cannot chalk!

[Mercury]

Epoxy cannot chalk!

Not sure why you believe epoxies cannot chalk as they are commonly know to do. Please refer to http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THD-4DF49HM-7&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=939720978&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=0930d5a80382945518537a7ab171eb5d

[apex1]

Nonsense, The paints can chalk, yes, the resin cannot!
Quote
The paints prepared using these resins and cured with amine terminated dimer fatty acid based polyamide (FPA) were evaluated for their weathering characteristics by subjecting them to accelerated and environmental weathering.Quote

[Mercury]

This is the second time you have invoked the word nonsense in what can only be described as some form of need to appear superior. The fact is and has been for many years Epoxies are renown for their chalking and many a company has spent millions overcoming same. Please do not bother yourself further to respond with such unwarranted language, I assumed the forum was for frank and open discussion and not attacks born from an alternate viewpoint.

Thank you.

Terry

[apex1]

Terry that was not really meant to attack you! Sorry for the word nonsense.
Using several tonnes of Epoxy resin per year I can assure you it does not chalk! It is impossible to chalk.
If we are talking paint (including epoxy based paint) chalking is a issue, yes. But your statement was not related with paint, you just said epoxy.

Regards
Richard

[Mercury]

Terry that was not really meant to attack you! Sorry for the word nonsense.
Using several tonnes of Epoxy resin per year I can assure you it does not chalk! It is impossible to chalk.
If we are talking paint (including epoxy based paint) chalking is a issue, yes. But your statement was not related with paint, you just said epoxy.

Regards
Richard

Thanks Richard, I knew you were a good guy at heart. It may be true what you say regarding epoxy not chalking but when researching epoxies (without paint or color additive) the manufacturer generally indicates will chalk if exposed to UV. What is it that you know different to these messages?

Terry

[apex1]

Thanks Richard, I knew you were a good guy at heart. It may be true what you say regarding epoxy not chalking but when researching epoxies (without paint or color additive) the manufacturer generally indicates will chalk if exposed to UV. What is it that you know different to these messages?

Terry

Nothing is different.
The resin itself cannot chalk, it deteriorates under UV light, but thats not chalking in technical terms. Of course the same is valid for any epoxy based paint, so they are not widely used by the industry except with a UV protecting coating. The fact that a submerged coating is not under direct UV influence is the next point to make any chalking issue speculative (as long as the hull remains submerged most of the year).
And thanks, I know I´m a good guy, but not by heart, by experience.

Regards
Richard

[MikeJohns]

..........this company supplying the Stainless can perform this as an option, problem being EPA banning of copper in most harbors on the West coast, The Netherlands has already banned copper in their waterways for leisure craft ..........extreme levels of cuprous oxide (copper containing paints) some of these measured levels have reached proportion of Super clean-up funding. I have viewed Coppercoat but I am not sure they have EPA approvals for use in the USA?

What experience do you have with the cheap popwder and epoxy, would not the epoxy chalk and breakdown?

Terry

No the epoxy matrix used in this way does not deteriorate.
Check that copper is banned as that would surprise me, the case is more likely copper oxide which leaches from the binder quite readily and is a toxin. Copper sheeting or copper powder in a matrix is quite different to the oxide. Copper and copper nickel are almost completely inert.

External heat exchangers are usually copper nickel and some boats have been built from this material too, they remain bare metal and resist fouling and don't corrode.

In Holland too I know there are copper bottomed trad wooden boats/ships abd they have no problems there.

[Kurt Sallaz]

Merury-
Have you considered UHMW as a bottom coating? I work with a bondable UHMW that when applied eliminates the need for any anti-fouling coating. An added benefit is increased hull strength. UHMW can be applied to wood, fiberglass, metal and concrete.

[Mercury]

Hello Kurt,

Thanks for your post. I am sorry but I am not sure what UHMW is?

Terry

[gonzo]

E-Paints came out with a new product last year. I haven't tried it, but the claim is that UV breaks it down and produces hydrogen peroxide which kills growth. It then dissipates into water and free oxigen.

[Kurt Sallaz]

Hello Kurt,

Thanks for your post. I am sorry but I am not sure what UHMW is?

Terry


It stands for Ultra High Molecular Weight polyethylene. It has extreme wear resitance. Alaska Air Boats, Thunder Jet Boats and Christensen Yachts are just a few companies that use UHMW for protecting their boat bottoms. It slides over rock bars with ease. It is used in the food industry to process sticky, sugary foods because they can't stick to it. That's why it makes such a good bottom coating- bio films can't stick to it either and being in contact with food, it's also eco-friendly. In water, it has 98 percent bouyancy factor. Once applied, it has the impact resistance of steel.

If more specific information is needed I will be happy to supply it via email or private message.

[MikeJohns]

It stands for Ultra High Molecular Weight polyethylene.

An added benefit is increased hull strength

It has extreme wear resitance.

it has 98 percent bouyancy factor.

Once applied, it has the impact resistance of steel.



Whilst it may make a good self cleaning coating I suspect it only applies to high speed boats. For the rest it will still need regular scrubbing as do the teflon coatings.

It cannot make your boat stronger since a more elastic coating than the base material will not contribute structurally until long after the base structure has yielded. And then there's the coating to base bond strength.

Once applied it may in some conditions exceed the abrasion resistance of steel to flat sliding surface abrasion but it is not going to improve collision resistance, it will only protect from some contact abrasion. Elastic coatings can be prone to rucking and peeling from the base in collisions.

Impact resistance is a very confusing term when considering highly elastic materials. An inflatable boat for example is virtually indestructable from a collision viewpoint. Much better than if the same boat were made of metal :)

[Kurt Sallaz]

Whilst it may make a good self cleaning coating I suspect it only applies to high speed boats. For the rest it will still need regular scrubbing as do the teflon coatings.

It cannot make your boat stronger since a more elastic coating than the base material will not contribute structurally until long after the base structure has yielded. And then there's the coating to base bond strength.

Once applied it may in some conditions exceed the abrasion resistance of steel to flat sliding surface abrasion but it is not going to improve collision resistance, it will only protect from some contact abrasion. Elastic coatings can be prone to rucking and peeling from the base in collisions.

Impact resistance is a very confusing term when considering highly elastic materials. An inflatable boat for example is virtually indestructable from a collision viewpoint. Much better than if the same boat were made of metal :)

While UHMW is "elastic" (subjective term) bonded to a rigid surface, it's impact resistance IS increased by the fact that it is now a thicker hull,
is now a laminated hull, now has an "elastic" componant to absorb enregy from an impact that might otherwise dent or crack a hull without UHMW just like an inflatable.

We have taken a piece of 1/4 inch steel with 1/4 inch UHMW bonded to it with epoxy and bent it in a 20 ton press to 90 degrees then flatened it out, turned it a quarter turn and bent it to a 90 degree angle again with no cracking or delamination. We have had a university do it's own independant testing on similar samples including shear tests and impact tests.

I'll attaching a comparison chart for anyone intrested.

As far as "scrubbing" (subjective) UHMW is easily cleaned by wiping. Bio-films cannot adhere to it.

[MikeJohns]

Thanks for your reply, bear with me but you probably need to put some numbers to your claims otherwise they are all subjective.

Arguments such as " it ends up a thicker hull so it must be stronger " are misleading of course they are correct but not structurally significant Remember that the elastic material is the extreme fibre....not where you would want it :)

Given that UHMW is significantly more elastic than other boat building mterials (more than 300 times that of steel ) it will never contribute significantly to strength any more than the foam in a foam core composite does.
It's a bit like glueing 1mm of polythene sheet to your 1mm car panels to make them stronger in collisions..... it will but not significantly.

Also consier that softer surfaces can be a two edged sword. If a colliding object (eg sharp rock) can dig into the surface then you could end up with a much higher load and considerably more damage than that which would have occurred if it had just glanced off a harder surface.

However considering anti-fouling all that would be required would be thin sheets I could see an advantage in having the material shear strength weaker than the epoxy bond strength which would prevent large sheets self peeling once/if they started particulalrly from an edge (eg after a collision).

What about gradual UV degredation of the waterline material ? Once this roughens it will foul.

I'd also like to see the long term immersion performance in sea-water.