Fresh Water Mooring

[johndf]

Next summer I'm planning to keep my boat on the river Rance near Dinan in a fresh water berth. Does this mean that I'll need a different antifouling, and what difference will it make if any to the sacrificial anodes I use?

I will be making occasional trips into salt water, every 3 or 4 weeks. I'll also have an extended salt water cruise, for about 5 weeks from late July.

Any advice gratefully received.

 

[byron]

John, you got no worries at all. Given the situation you describe you do not even need to bother anti-fouling as the forays twixt salt and fresh will kill all growths.

http://www.alexander-advertising.co.uk

 

[snowleopard]

canal water...

just back from 2 months in the caledonian canal, now hauled out. nothing but a bit of slime on the bottom and anodes are fine. if staying permanently in fresh water you should change to magnesium anodes but no need short term. enjoy the trip

 

[vyv_cox]

Re: canal water...

We are berthed in fresh water on the Haringvliet and sail at sea when possible. Fresh water fouling is confined to a thin, black slime that is easily removed by scrubbing. An anti-fouling that resists sea-water fouling is used by most owners in a similar situation to myself and International recommend a grade one down from their top of range, i.e. Cruiser. The problem with using erodable antifoulings is that scrubbing to remove the fresh-water black slime removes the antifouling as well, not only reducing its effectiveness (not that it is very effective, anyway) but polluting the water as well.

My answer is to use hard, scrubbable antifouling. The black stuff scrubs off easily without damaging it. Any seawater fouling that does accumulate is killed off once you return to fresh water.

The new Interspeed Teflon is supposed to be quite good but I have yet to try it. However, I suspect that using no antifouling at all would be just as effective.

Definitely stay with zinc anodes, seawater will kill magnesium ones very quickly.

 

[johndf]

Thanks very much for the help NM

No message
johndf

 

[heerenleed]

Don\'t know about zinc anodes...

working well if the boat is kept in fresh water. As many Dutch keep their boats in fresh water, this is a common problem in the netherlands. We have always been told not to use zinc anodes if the boat is kept in fresh water, as the anode will cover itself with a layer of oxide which stops it working. that's why we all use magnesium anodes and yes, we change them every two year. We spend most summer weekends in sea water, and a month during summer holidays. But on week days and in winter we are more or less permanently in fresh water.

Magnesium anodes might be very difficult to come by outside the netherlands i suppose.

happy sailing

Peter a/b SV Heerenleed, Steenbergen, Netherlands

 

[Viking]

Interesting you should say that.
Here where my office is there's a marina, which has open access to the sea. But at one end there is a fast flowing fresh water stream which flush through the marina.
I have noticed is the few months I've been here that the boats have no fouling. Compared to mine which is exposed to sea water all the time.
The stream does attract salmon and shoals of mackerell.