Urban myth or??????????

Laysula

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We are currently up river in Pontrieux, Brittainy. We are upriver of a lock which keeps the river level artificially high. consequently we are moored in fresh water. it has been mentioned that after a couple of days, any weed or fouling will just die and drop off.Does anyone have any experience of this? Is it a myth:(? Or will it happen:)?
 
I keep my boat on a non-tidal river in France and she has not been anti-fouled in 4 years. Her bottom and propeller are clean. The freshwater fouling dies when I go to sea and the marine growth dies when I return.
 
Yes, it will kill most living things which are sea water reliant.

We bought our current boat from a berth in Gloucester Docks where it had been for two years. only a little freshwater weed on the sunny side of the waterline.

As the antifoul was seven years old, it grew pretty quick once back in the sea!
 
I think that the best that you can hope for is that it will hold things as they are for a while. If fouling has attached itself to your paint, then the antifouling effect will be negated, but a period in fresh water is better than nothing, but dropping off to any great extent may be optimistic.
 
I kept my last boat at Crinan for many years: swinging mooring for the summer and canal for the winter. The second summer I dried out on the grid at Kilmelford and slapped on a coat, though there was hardly any fouling. I didn't bother again for four years and had no issues.

Later I kept the boat on the pontoon in Kirkcudbright, which has huge salinity changes from almost fresh near the bottom of the ebb to Irish Sea saline towards the top of the ebb. After seven continuous years I dried her out and there were only two small patches of barnacles, each less than the area of an A4 sheet.

I don't know how quickly the fresh will have an effect, but it will have one.
 
We only have a little bit of slime and a little weed growth around the waterline. No barnacles. Antifoul (International micron) is now 13 months old and we don't expect to renew it until next spring. I was just hoping that the little bit of fouling that is there would just drop off. Too good to be true I suppose.
 
We did not antifoul for 3 years thanks to being based in Sani marina in Greece. It's a small circular marina open to the sea but also acts as the rainwater drainage point for extensive resort grounds. So every few weeks at least there would be a deluge and the sea water would be replaced by muddy fresh water visibly going out to sea. And as well as hundreds of fish going belly up in the marina it seemed to kill off salt based growth whilst never lasting long enough for freshwater growth to happen. So in an alternating environment it does seem to be true.
 
I kept my last boat at Crinan for many years: swinging mooring for the summer and canal for the winter. The second summer I dried out on the grid at Kilmelford and slapped on a coat, though there was hardly any fouling. I didn't bother again for four years and had no issues...

+1

I was in the Crinan canal for the best part of ten years and didn't antifoul during that time .. midweek in fresh water and salt at weekends kept the hull clean as a whistle.
 
Only here for a couple of days, heading back to sea this evening. I will report back if there is any change to the hull. I don't anticipate any problems with the prop. It's a Kiwi which is stainless steel and plastic anyway.
 
Cruising the East Coast we usually have spent a week or so in fresh water during the season and it does seem to frighten the barnies?
Of course I don’t know what it would be like otherwise.
 
We have just dried out against the wall at Perros Guriec to remove 5 metres of rope from around the prop, but that's another story, the boat is really clean underneath, no slime just a few very tiny barnacly things on the exposed stainless steel bit of the kiwi prop which easily scraped off with a penknife, and some very fine bits of weed on the waterline at the bow. The anti foul is looking very thin and I'm not sure that it will last through to next year though.
 
At Glasson, Lancashire the marina is in a canal basin where the water is predominantly fresh. The boats transit into the Lune estuary via a lock and a gated salt water dock. My own experience and that of others is that boats which make the transition on a fairly regular basis stay pretty clean. Boats which stay in the marina long term collect the green slimy of growth typical of fresh water. Boats moored permanently in the estuary collect the usual barnacles etc.
 
We have just dried out against the wall at Perros Guriec to remove 5 metres of rope from around the prop, but that's another story, the boat is really clean underneath, no slime just a few very tiny barnacly things on the exposed stainless steel bit of the kiwi prop which easily scraped off with a penknife, and some very fine bits of weed on the waterline at the bow. The anti foul is looking very thin and I'm not sure that it will last through to next year though.


Glad you are getting out and about in your new boat.
Your old boat still has the same AF that you last applied to it how many years ago? I will admit that we were glad to be back in dock after an extended cruise to Ireland.. We were worried that any stay in sea water might have left something sticking to her bottom. Even more so after visiting Arklow the cesspit of Ireland. We did notice a slight beard growth on the rudder after 10 days away. Seemed to scrub off with the slightest touch of a broom in the crystal clear freshwater of Felinheli Dock. No urban myth!
Steve
 
It works in the tropics as well.

We spent 6 months in Brazil where the fouling rate is incredibly high - we had to dive and scrape every 3 weeks or so - and then spent a couple of months in the creeks in French Guiana and in Suriname where I measured TDS at <35ppm (drinking water is about 3x and may be unto 10x this amount of salt). All fouling fell off the Coppercoat within a week or so, and the outboard and loo benefited as well.
 
every few weeks at least there would be a deluge and the sea water would be replaced by muddy fresh water visibly going out to sea. And as well as hundreds of fish going belly up in the marina it seemed to kill off salt based growth

Sure that was mud?
 
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