oldharry
Well-Known Member
TBT was the best AF but got banned many years ago because it was so harmful to the environment. Not a good idea.
Lanolin vs lanolin and extra hot chilli powder - the results
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TBT was the best AF but got banned many years ago because it was so harmful to the environment. Not a good idea.
ronsurf
Well-Known Member
In the case of TBT, 'harmful to the environment' actually means it gets into the food chain, bio-accumulates and eventually ends up in humans.
I can understand the case against TBT for large commercial vessels, I can even understand the case against TBT in leisure vessels. But the case against use on a propellor? Like dead seahorses - I doubt that there has been a study that will stand scrutiny.
Jonathan
Jonathan
ianj99
Well-Known Member
I think you'll find TNT far more effective, though there is a side effect..
oldharry
Well-Known Member
.... Gives good initial acceleration
ianj99
Well-Known Member
True but not necessarily in the desired direction.
Daydream believer
Well-Known Member
Anything that stops those worms ending up inside one might be worth having in the food chain
Arguably TBT and a clean prop is better than a fouled prop and using more fuel, or the energy implications of slipping to clean etc
Jonathan
Jonathan
AntarcticPilot
Well-Known Member
One of the nastier side-effects of TBT is to mess up the gender of affected organisms. It accumulates up the food chain, and has been implicated in the deaths of mammals such as sea-otters and dolphins. It acts as an immunosuppressant in vertebrates. It persists in the environment for around 20+ years. If you allow it for propellers, how are you going to stop its wider use?
TBT is seriously nasty stuff, and the ban was brought in because it was beginning to affect commercial fisheries, both by causing population declines and by accumulating to potentially toxic levels in commercially caught fish.
I do not doubt the science, at all, for the ban for wholesale use of TBT - but on props. We are, or some are, willing to pay a fortune for PropSpeed/Gold (and have not had time for any environmental impact (but the primer itself is very unpleasant). If a small tin of TBT prop paint cost Stg'a lot' and it were allowed then economy would dictate its limited usage. Restrict sale to 250ml max?
It is difficult to believe it could not be restricted in its application - and if that is the only reason not to use it then someone somewhere lacks imagination.
its whether science has been conducted on such a small item and looking at the benefits of its usage in that application over the alternatives.
Jonathan
It is difficult to believe it could not be restricted in its application - and if that is the only reason not to use it then someone somewhere lacks imagination.
its whether science has been conducted on such a small item and looking at the benefits of its usage in that application over the alternatives.
Jonathan
AntarcticPilot
Well-Known Member
ALL antifouling formulations are subject to tight regulation; they are only allowed to use permitted substances. The cost of things like Propspeed etc. is because they a) don't contain much, if any, poison (they act by creating a surface fouling organisms can't attach to) and b) because of the research and testing required to ensure they meet the regulations.
Given the lengths some people (no one reading this, I'm sure!) will go to to be competitive, how long do you think it would be before someone bought lots of the 250ml tins you propose to treat their hull? If you want a ban to stick, the only safe way is to make it absolute.
All this is moot. TBT is banned by International treaty, not merely national law, so there is no chance of it being legal anytime soon.
Pasarell
Well-Known Member
TBT was never a successful antifouling for props. It is a biocide that needs to be added to a resin to get it onto the surface to be protected. It was known about for a long time but only took off commercially when a couple of chemists at International came up with the daft idea of a paint resin that slowly dissolved in water in a controlled way. At first the idea was canned as too ridiculous but eventually appeared as the first SPC, self polishing copolymer. International were a strong marine paint company before but this allowed them to clean up the market worldwide but only after some difficult sales pitches. On hulls of ships and yachts it was fantastic. On propellers it was a non starter. A polishing paint resin gets eroded far too quickly at the tips of the blades and not enough to release the TBT around the hub. More importantly the vortexes that form around the tips of propeller blades destroy pretty much any paint system in a very short time. The coating is simply ripped from the surface. Which brings us onto why the primer for Propspeed needs to be so unpleasant.....
Thanks Pasarell,
proves a number of things
There are very few new and good ideas
And we really have not solved the prop problem
, unless you think Propspeed a good idea.
Jonathan
edit, I'm not forgetting Velox, the jury here will take a long time to come to a decision.
proves a number of things
There are very few new and good ideas
And we really have not solved the prop problem
, unless you think Propspeed a good idea.Jonathan
edit, I'm not forgetting Velox, the jury here will take a long time to come to a decision.
vyv_cox
Well-Known Member
Third successful season with Velox. This taken yesterday before pressure washing. Absolutely nothing on it, whereas in previous years it would have been heavily coated with tube worm. This is two coats on top of previously applied Hammerite primer, sanded down. Slight pitting of the top coat due to cavitation but much better that when i applied four coats as recommended. After three years I still have well over half a tin of velox left, so a pretty economical treatment.
Edit: P bracket also perfectly clean, compare with prop shaft in the background.
charles_reed
Well-Known Member
Having tried most things (Trilux, lanolin,udder cream, grate-black), I've found polishing the prop and then regular use is the best method of keeping it clear - mine's an Autoprop not a folder or a Maxprop but even more likely to malfunction due to fouling.
The only problem with polishing is that sooner or later the blades will need replacement - that painful moment has just arrived, after 22 years, they'll cost 25% more than the new prop did!!
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charles_reed
Well-Known Member
One gets them toward the end of every summer in the E Med - usually they gang up on the log paddle-wheel, though this year in 1483nm I haven't had to clear the paddle-wheel. I find the easiest way to clean them of is to put the paddle-wheel in a solution of sulphamic acid and leave it for 24 hrs, then shake out all the little bodies. On prop sprague and boss they're easy to clean off by scraping but more of a problem on zinc anodes (I now use a wire-brush on an electric drill). This gets off the zinc-oxide as well as tube-worms.
Your prop looks real clean, but then so does the hull.
How long were you in the water? Has the hull been washed down and if not what AF are you using.
Jonathan
charles_reed
Well-Known Member
But still available for large merchant vessels.
Strictly speaking, because they kill weed and sea animals ALL anti-foulings are harmful to the environment.
Pasarell
Well-Known Member
Oh no it isn't. TBT is now banned. Completely. Everywhere. Has been for a number of years and in practice European / US / Japanese ship owners stopped using it many years ago so it was off the majority of deep sea vessels by about 2000.
I'm sure you can still find it in some 3rd world countries for use by fishermen and coastal traffic but try going into any major port with TBT on the bottom and there will be a shed load of trouble, including the ship arrested.
I'm sure you can still find it in some 3rd world countries for use by fishermen and coastal traffic but try going into any major port with TBT on the bottom and there will be a shed load of trouble, including the ship arrested.
Slow_boat
Well-Known Member
I have used grate blacking to good effect for the last two years. It no longer has lead in it but still seems to work. Bottom and prop were very clean this year but that may be partly due to two weeks in freshwater before lift out.