Antifouling propellers

[Clipper]

Could someone please advise on the latest methods for priming and antifouling propellers and underwater metal (shafts and rudders in 316 S/Steel). The props are made from NiAlBr. Thanks.

[Landlubber]

I have found that one of the best ways is to paint first with International PA10, followad by Interprotect then use your favourite antifouling.
Hope this helps a bit, there have been over 100 people looked, but no replies to date.

[Frosty]

With a high speed prop its my opinion you would be waisting your time. A look round the local boat yard should reveal that not may people antifoul thier prop.

I found that the only way to give it half a chance is to antifoul it the first day your out giving it the longest possible drying time. A good sanpapering up with 100s and give it as long as possible to harden.

Use a hard not an ablative or self polishing and you might get away with it.

[Frosty]

Clipper I just noticed that you have bronze prop's and stainless rudders.

Your going to get some electrolisis corrosion. Is this why you ask how to keep antifouling on?

At a guess I would say that you are,- and the antifoul just peels off the rudders ? yes?

[waikikin]

I have had good success with the International PA10 primer on most(not all) occassions as well, some leave nothing on it & if in frequent use works well, some have been slathering lanoline onto a blow torch(looks dodgy) warmed prop & claim great success & a firm even roasts the prop & dip it in although this might make paint harder to stick in future. Jeff.

[MikeJohns]

On larger commercial vessels we always epoxy the shafts and the prop sometimes the shafts are done in epoxy and glass mat.

Epoxy has a very good electrical resistance and stops the galvanic corrosion that can be particularly severe in the dissimilar shaft prop area. Ship props are often coated with proprietory coatings which are so smooth that they offer poor purchase for biofouling.

We usually specify a hard specific prop antifouling over epoxy. As Frosty says above a high speed prop quickly erodes paint particulalry the leading edges. Slower displacement hulls with bigger slower props are usually ok. A smooth well applied epoxy over an etched prop sticks surprisingly well. some people just epoxy and clean what doesn't fly off by scrubbing once a month, in colder climates this isn't an option.

It is always advisable to contact your paint reps and ask them what products they would stand behind.