Antifoul on Stainless rudder

[nordicstar]

My Scanyacht 290 (UK version of LM27) was built with an aerofoil shaped rudder fabricated in stainless steel. On my boat the antifoul peels off where the prop pushes water over the surface.Has anyone with a similar rudder found an answer to this problem?

Thanks

David 

[Sula]

What sort of anti-foul are you using, and did you use a primer?

[Charlie]

Hi David
I have a stainless rudder (local boat yard replacement after loss of original on a LM27). 
I use Hempel Prop Primer - Then the Hempel overcoat - works really well.


Hope this helps
Charlie


Spec herewith.


HEMPEL
INFORMATIONTECHNICAL & SAFETY SHEETSREVIEWS
Aerosol. An anti-corrosive primer for a large variety of substrates.
Particularly recommended as a primer for outdrives and propellers.
Prop Primer has very good adherence to most substrates. Fast drying, easy to apply with a matt finish.
Overcoat with Mille Drive or appropriate antifouling Gel/High protect.

Minimum Application Temperature : 5°c

[nordicstar]

Hi Charlie - thanks for your helpful reply, and I will follow up on that.

Sula - Yes the rudder had been primed by the previous owner, but I don't know what with, and I cant find out. (it's not effective anyway!) This is the first year that I have had the boat ashore, as the hull is Coppercoated, and previously I have just beached her to clean the prop and change anodes. I did patch up the bare patches on the rudder with Velox primer, overcoated with Cruiser Uno, but this was a between tides job, so not ideal. I thought there might be other LMs and Scanyachts with stainless rudders, so that the answer would be well known!

[Charlie]

Hi David
Unless any other members can help - I suggest sanding off it all the old primer and starting again.
A least you’ll know it a good job .

Take care
Charlie

[pengwyn]

antifouling-alchemy

on my LM27 a becker type rudder made of stainless steel is installed. When I bought the boat years ago, the rudder was already coated in multiple layers of black antifouling. The boat is stored ashore in the winter and every year I added another layer of antofouling (after removing tons of ‘fouling-civilisation’ from the rudder). Obviously the antifouling would have grown into a large, black underwater reef, if the process would continue for another couple of million years. In the continous process of ‘improving’ the boat, I removed all that ‘geolocical layers’ from the rudder (and the hull, which was really a mess). After sanding and cleaning, the shiny, properly degreased rudder was treated with special underwater primer (International) and protected with stylish (blue) hard-antifouling (Yachtcare) towards the propeller, whereas the rest of the rudder (and flap) was painted with self polishing (red) antifouling (Yachtcare). As a result, the built up of the ‘fouling-civilisation’ was faster and more pronounced than ever. Also patches of antifouling and primer went off the rudder (not only close to the propeller), leaving shiny metal behind, which was instantly populated by fouling-creatures within a few weeks. Variations of the theme (number of primer-layers, various types of antifouling and location) showed no improvement over the years. (To my surprise, the GRP-rudder of my windpilot, quite close to the main rudder, painted with the same selfpolishing antifouling, was hardly affected by fouling and no patches of paint went off. Are there any effects of temperature, light or metall known to have an influence on fouling? Also the hull (black, self polishing antifouling, spiced with Cu) is much less affected by fouling than the rudder & prop – exept for the paddel wheel of the sumlog, which I have treated with 'special' (=expensive) ‘space tech’ teflon™ log-coating. The fouling cratures seemed to love this ‘superfood’, forming a pronounced colony on that spot.). This season I’ll use conventional black self polishing antifouling and no primer and will hope for the best. In addition I’ll try to find out, how to coach seaguls not only to bomb the deck with poop, but dive and eat the fouling from rudder and elsewhere. But I’ afraid, a ‘plan C’ will definitely be required, consisting of snorkel, flippers, a scaper and a brush.

Pen Gwyn