Barnacle Prevention

[JamesG]

Is it possible to prevent barnacles and other marine life from forming on a hull? I found this device online, but do you think it really works?

http://www.brightspark.nl/site/anti_fouling.html

Anti-fouling paint just slows the critters from growing, right?

[Landlubber]

Keep the boat out of the water.

[Submarine Tom]

Originally Posted by Landlubber

Keep the boat out of the water.

That's what I was going to say!!

Tom

[JamesG]

That's really creative

[Submarine Tom]

Not really, just common sense.

Tom

[marshmat]

Applying an electric field underwater (as the device in post #1 appears to do) seems like it would cause many headaches over corrosion, and its effect on fouling organisms seems questionable at best without more data.

Conventional anti-fouling paint works by being so heavily laden with toxic substances that nothing wants to live on it. Copper, for example, which is deadly to many aquatic plants.

Recently there have been some new anti-fouling coatings that claim to work by either being so smooth that nothing can grip well enough to not get washed off, or by having such a low surface energy that anything that attempts to bond to it is repelled at the sub-molecular level.

[rwatson]

Some "with and without " photos in the November 09 copy of Australian "Trade a Boat" look very impressive

[JamesG]

Here's the website for the 2b Sure system. http://globalmarinegroup.com.au/2b-sure

I emailed them about it and asked if they wanted to join this discussion. Hopefully they can provide data or proof.

[JamesG]

Originally Posted by rwatson

Some "with and without " photos in the November 09 copy of Australian "Trade a Boat" look very impressive

They sure do! I hope its for real!

[JamesG]

Here's another product from the same company. It puts the boat in a separate water source which is supposedly free of oxygen. No oxygen= no sea life attaching to your boat. http://globalmarinegroup.com.au/boat-bunkers

[globalmarine]

Originally Posted by JamesG

Here's the website for the 2b Sure system. http://globalmarinegroup.com.au/2b-sure

I emailed them about it and asked if they wanted to join this discussion. Hopefully they can provide data or proof.

Hi All,

I'm respoding to an invitation made by a member of your forum. I'm hear to answer some questions that have been asked and comments that I have read.

Please read an extract from the manufacturers document. Should you like to read the full document please contact m and i will happily forward you the full document and help with anyquestions you may require answers to.

extract:
Alternative Anti-Fouling Pigments.
The technical literature recites numerous compounds to which anti-fouling activity has
been assigned.
Typical are - copper resonates
- copper arsenite
- calomel
- copper oxychloride
- basic copper carbonate
- selenium oxide
- copper and zinc selenides
- cuprous cyanide
And numerous arsenic compounds.
In addition, a wide variety of organic compounds have been described and patented as
anti-fouling toxicants.
The use of certain metallo-organic complexes has been widely explored in recent years.
In general, it can be stated of these alternative pigments that few if any are as effective
on a “pound-for pound” basis as a simple copper scale, copper, or cuprous oxide, and
non can presently compete on a “cost-per-pound” per month of effective paint life.
Other Measures
Use of Electric Currents
As we know numerous investigators have suggested the possibility of applying either DCor
AC current to the hull at intermittent intervals, to prevent primary attachment.
* The larval forms of most fouling organisms are remarkably insensitive to DC-current
without intervals.
High-frequency AC-current has also been employed on an experimental scale, with
little success to date.
* Anti-Fouling System by impressed DC-current with intervals is the ultimate solution,
to avoid deposition of calcium, magnesium, and strontium basic salts as an
adherent film (appears to be a limiting factor).
Theory of Anti-Fouling.
Anti-fouling paints (for instance hull-protection of vessels, water inlet systems, etc.) are
active when leaching rates of copper oxide exceed 10 microgram/cm2 per day, which
means that a surface of 1 m2 can be kept clear of biological growth by leaching of
approximately 30 gr. of copper oxide/year.
Marine Fouling/Automatic Electrolytic
Fouling Prevention.
This is an automatic electrolytic process for the prevention of fouling by growth of wiry
type algae, shellfish, mussels, coral and barnacles.
The system is based on the same principle as the use of marine anti-fouling paints where
copper pigments are used for provision of a toxic medium.
It is established that cuprous oxide leached from the paints has a strong toxic action on
growth such as algae, shellfish, barnacles and other growth.
Similar amounts of copper oxide are active in our “2B Sure-System”.
Whereas anti-fouling paints are only active during the period the leaching rate is over the
given quantity, in our “2B Sure-System” cuprous oxides are formed continuously in controlled amounts and similarly the action against growth and developments of algae and shellfish,etc is continuous and controlled.
It would appear that the use of electrolytic red copper as anodes only could have
dangerous consequences.
Corrosion cells can be established when dissolved copper is displaced from solution and
redeposited on steel surfaces.
However, this possibility does NOT and CANNOT occur in the conditions of use since in
the first instance the quantities of copper going into solution are negligibly small and
secondly this copper does NOT remain as dissolved copper, but is immediately oxidized
to copper oxides, which are insoluble.
Both cuprous and cupric oxides are insoluble so that the amount of copper ions in water
is untraceable and far below so called natural levels.
For environmental reasons Aluminium Anodes can be used in combination with Copper
Anodes, because direct current (= DC) dissolution of aluminium alloys results in
formation of “colloidal” solutions and hydrated aluminium oxides or “floc” which is
gelatinous and encapsulates the precipitated copper oxides so that they are removed as
a sludge.
Similarly, “suspended” impurities in the water are removed so that cleaner water is
produced.
Example.
The quantities of copper forced into solution are relatively small for example a water inlet
of 600 m3/hour, we dissolve only 80 kg of copper per year, and that means less than
0,02 ppm or mg/kg of which most of the copper is precipitated and 20 kg of aluminium
per year.
Designs of Automatic Anti-Fouling System are based on type of: - water
- flow rates
-conditions and fouling character but the amounts of copper (Cu) and aluminium (Al) dissolved will be of this relative magnitude.
All immersed steelwork via electrolyte connected to the Cu-and Al-anodes will be fully
cathodically protected and the corrosion rate of allied pipe work down stream reduced by
reduction of dissolved oxygen in solutions and the formation of mixed Fe-Al-oxide
crystals at the steel/pipe surface.
Advantages.
- The system as disigned and developed by , Bright Spark, can be regarded as a
perfectly safe system.
Not only on account of the corrosion dangers, but it will not create any danger for
handling personnel, nor will it give any pollution effect in the effluent.
- The system will need little care and maintenance and with the exception of replacement
of worn anodes (once a year as minimal), will work fully automatically.
- The system is Affordable. Running costs are low, low consumption since the system works at very low voltage.

[Ad Hoc]

Very very interesting research being done at ONR, they have developed a new biomimetic technology called "sharklet" utilising the unique skin of sharks at Uni of Florida, and also at Uni of Washington developed Zwitterionic or mix-charged compounds. These are stable alternating between positive and negative charges.

[apex1]

Sounds logical..............
never seen a shark with barnacles round his head.

[Ad Hoc]

yes, kind of obvious when you think about it...but that is what Prof Brennan thought when he looked at sharks!

[capt vimes]

ad hoc:
you have a link to this 'sharklet'?

i know that sientisct have been trying to mimic sharkskin for centuries... it also has the advantage of reduced frictional drag...

you know that the 'glue' barnacles using to attach them to their substrat is 10 times stronger than any resin we know and use?