WWW.RLYACHTS.NET
RL24, RL28, and RL34 Trailable Yachts
from Rob Legg Yachts

RL Yacht Owner's Discussion Forum

Return to the Forum List

A New Environmentally Friendly and Effective Antifouling paint
From the GIZMAG new technology website:

Researchers identify gene that causes barnacles to avoid ship hulls

By Darren Quick
23:35 August 17, 2010

Fouling of hulls is a major problem for world shipping – for private leisure craft as well as large cargo ships – with barnacles being a major culprit. It reduces the performance of vessels and increases their fuel requirements. Medetomidine has proved effective in preventing fouling of ship bottoms and now researchers attempting to develop new, environmentally friendly methods to limit marine fouling have identified the gene that causes barnacles to react to the substance, opening up the possibility of an antifouling paint that is gentle to both barnacles and the environment.

Medetomidine is a veterinary medicine that has been shown to prevent barnacle larvae from attaching to ship’s hulls. In cooperation with colleagues at the universities of Turku and Helsinki, Professor Anders Blomberg at the Department of Cell and Molecular Biology at the University of Gothenburg has succeeded in identifying and describing the gene that controls how barnacles sense and react to medetomidine.

When the barnacle cyprid larva encounters a surface containing medetomidine the molecule enters the octopamine receptor in the larva. This makes the larva legs start kicking and it cannot settle to the painted surface. This is a reversible effect that disappears when the larva swims away from the surface so it regains its function and can settle somewhere else.

The results, which are published in the scientific journal Molecular Pharmacology, explain how it is possible to develop an environmentally friendly and effective antifouling paint which instead of killing barnacles acts as a “deterrent”.

“Understanding how the substance works when it binds to the receptor also makes it possible to develop selective agents that only affect barnacles and not other marine organisms,” says Professor Blomberg.

Alastair22-Aug-2010    Edit    Delete 
Re: A New Environmentally Friendly and Effective Antifouling paint
Sounds like a great area of research. We would all like to think that we are doing no harm but the number of boats with toxic antifoul must be making an impact. Whilst I eventually see small shell fish which may be barnacles, there is a greater problem here with Algae and weed. I wonder if they can produce a cocktail of similar "drugs" to deal with these as well?
Russell29-Aug-2010    Edit    Delete 
Re: A New Environmentally Friendly and Effective Antifouling paint
Russell

An accidental environmental problem was apparently created way back in the sixties when the paint companies introduced the aggressive biocide Tributyltin (TBT) into ships and boats anti-fouling paint. The new paint was welcomed with open arms as it worked well and stopped the attachment of the dreaded barnacles and also the growth of the algae and weed that you mention. It was a top product!

This new paint along with improving the design of the stern tube and sealing systems used, kept the ships in service much longer and away from the costly dry-docking procedure. New ships were then being fitted out with oil lubricated stern tubes along with a modern and efficient stern tube sealing system. They used hard wearing and expensive synthetic viton rubber in the stern tube seals. Up until then ships were dry docked, usually every 12 to 18 months depending on the type of ship and type of service. During this period the shipowner was only too happy to spend a dollar if he could reduce his ships fuel consumption and maintenance costs especially during the fuel crisis in 1973.

I think the Japanese were the first to ban this new paint from being used in their dry docks. They stated that they were experiencing occupational health and safety problems with the use of the TBT paint as it was thought to be affecting the health of their employees. International shipowners got round this problem by then dry-docking in only third world countries where OH and S was low in the pecking order!

The French then proved that the TBT paint was affecting the growth of their oysters and mussels in beds which were close to boat marinas. Apparently it was creating a sex change in the male oysters! This was caused by all the yachts in the marina spending most of their time tied up and as a consequence was allowing the TBT in the paint to leach out and into the water in a concentrated fashion

TBT paint has been banned for a few years in recreational boat paints and it is only recently that TBT anti fouling has been banned from commercial shipping. As you have noticed we are all again experiencing algae in weed problems which of course can create boat speed problems for the keen racers. When I was a keen racer I used to scrub my folkboat’s bottom twice a season and as required by the rules, I always informed the handicapper in loud voice that I had done so!

I will finish off by saying that many small Asian fishing boats use ordinary house paint to paint their boats and all they do is add a heap of hot chilli powder to the paint when doing the underwater area!

Way back I was on a ship chartered to carry AUS wheat to Malaysia. Prior to loading we were strike bound in Walsh Bay for three weeks with an old and weak Japanese non TBT paint job underwater. When we left port and tried to get the fully loaded ship up to her full speed the main engine overload alarm went off and it was found we could not do our contracted charter speed because of hull fouling. Apparently the old Walsh Bay wharfs in Sydney were famous for this problem and that a species of barnacle growing on the wharfs there is noted and unique (a super barnacle)! The wharfs are still there and this area is now a marina?

When we bunkered in Singapore we got the brush boat divers in to clean the hull and all our super / Sydney barnacle did was rip hell out of their revolving brushes. They did remove the slime and weed and we did get a slight increase in sea speed to cover our charter speed...

Alastair12-Sep-2010    Edit    Delete 

Return to the Forum List       Add a message to this discussion