Cu-electroplating of propellers: barnacles, cupper and zinc anodes.

[MagnusS]

The tests that the OP refers to take place on the Swedish westcoast, not in the Baltic proper.
Along this coast the salinity of the surface water is only a little lower than in the oceans, around 30 ppt on average.
Besides, fouling by barnacles is a problem for boatowners also in the Baltic, as some species are very tolerant to low salinity.

The barnacles in the Stockholm archipelago with its Baltic water are far from humble either....
This picture is from a boat taken out of water earlier today near Stockholm.
.

 

[MagnusS]

There seems to be confusion about the salinity at the Swedish westcoast where the propeller copper plating trials are made. It is about 3%. (Most ocean waters are 3.5 %)
(In the Stockholm archipelago it is about 0.8-0.11 %.)
The Swedish westcoast has a summer season water temperature beginning at 12 Degrees at the end of April, over 19 degrees from June to September, and then 14 in the beginning of October.
The waters are very rich of plankton of all kinds, daylight during several months is between 4 am to 9 pm. Any and all biological creature thrives tremendously well in this environment, and the growth is as bad as the worst worldwide.

BTW, it seems as some of my postings does not get through.....

 

[Neeves]

You call that fouling?

Magnus - you did not comment on your earlier image where I queries the difference visual effect on the saildrive and hub being totally different to the blades. The blades and hub are electro plated, but are totally different - the hub is white and streaky brown and the blades black, The saildrive is streaky brown.

It certainly looks as if the hub and saildrive have been AF, though this AF looks very clean. But as the hub has been plated and if plating is so successful - why coat it with AF?

Jonathan

 

[lpdsn]

Mention is made of salinity. And one might also make mention of temperature.

Magnus is referring to application in the Baltic, where salinity is 'lower'(?) and temperatures also 'lower' (?) - I tend possibly erroneously to think of the Baltic as both cold and brackish.

The Baltic warms up quite significantly in the height of summer. I think it gets up to 20 deg C at times, so certainly a fair bit warmer than the North Sea.

 

[Neeves]

I recall, in my youth, swimming in Scotland with ice or snow still on the banks of the burn and summer holidays were spent at Elie or St Andrews with the main attraction being the (North) Sea. Now I find 20 degrees decidedly uncomfortable, immersion only through dire necessity, 24 is bearable and 26 becoming comfortable.

Jonathan

 

[rogerthebodger]

You call that fouling?

That's what I was thinking also

Our average sea temperature in summer is 25 to 27 C and winter 20 22 C I would get that kind of fouling in 4 to 6 months but would look much rougher.

I anti foul every 2 years but have to dive to clean my prop every 4 to 6 months.

 

[MagnusS]

You call that fouling?

Magnus - you did not comment on your earlier image where I queries the difference visual effect on the saildrive and hub being totally different to the blades. The blades and hub are electro plated, but are totally different - the hub is white and streaky brown and the blades black, The saildrive is streaky brown.

It certainly looks as if the hub and saildrive have been AF, though this AF looks very clean. But as the hub has been plated and if plating is so successful - why coat it with AF?

Jonathan

Sorr for the confusion. I do not hav all the picturs. The two Volvo 3-blad propeller pictires does not show the same propeller individual. But the blades for both have had exactly the same treatment. The propeller shown "after" has it´s hub epoxy-painted, and then painted by the same antifouling paint of the same type as the s-drive. OK?

 

[MagnusS]

The owner of the Volvo 3-blade propeller with the epoxy/antifouling painted hub have just sent us a picture showing his propeller the other day.
This spring he did not renew the hub antifouling paint. Thus some barnacles there. The blades have now been used full 5 summer seasons without renewing the copper plating.
Location is the Swedish West Coast with a salinity of about 3 %.

 

[thinwater]

Re. The photo, we don't know the time frame. Those anodes don't look like it has been very long.

 

[MagnusS]

The owner of the Volvo 3-blade propeller with the epoxy/antifouling painted hub have just sent us a picture showing his propeller the other day.
This spring he did not renew the hub antifouling paint. Thus some barnacles there. The blades have now been used full 5 summer seasons without renewing the copper plating.
Location is the Swedish West Coast with a salinity of about 3 %.

Sorry, trouble with the picture. But here it is.