Prop Shield

[nimrod1230]

I have done a quick search and found some discussion of the possible benefits of Prop Shield but no reports of actual results now that most people will have lifted out for the winter?

 

[Miken]

I treated my Saildrive prop with it at the beginning of the season and also did the saildrive leg with Trilux. Results

Leg OK

Prop very heavy fouling (Proshield did not appear to do anything)

Therefore wont be using it again

Regards

 

[double_ender]

I used propshield last season, and I would give it 6 out of 10.

The boat was afloat mid march - October on west coast of Scotland. The prop is 13 inch with about 250 hrs on the engine. Over the last 10years I've tried everything with no joy. Usually by August I have to underwater scrub the prop to remove grass like long strands which reduces prop effectiveness.
This year with propshield I thought it was a write off as after 2-3 weeks there was no red colour visible on the prop. But as the season progressed there was no long strands growing and there was no need to remotely scrub with the broom. From the photo below you will see there is a growth coating but it is short and has had little effect on the prop.

So I think 6/10 or maybe a bit more as it has kept the prop free of long weed. Or maybe its been a better year for weed growth!

One method I heard about some years ago was the use of stove polish called I think Zeebrite or similar. It was a colloidal graphite which I thought might have an electro corrosion effect on the bronze prop. So I ducked out of that one
Has anyone experince of this graphite treatment?

 

[Miker]

I'd give it 9 out of 10. My 26 footer is in the water in a marina from April to October each year. Last year the Autoprop blades were heavily encrusted with limpets, so much so that the engine revs and speed dropped off towards the end of the season. This year there were only a few limpets on the blades. I painted the prop shaft with antifouling which was less effective. The limpets were still around and had migrated to the bottom of the keel where it had scrapped on the mud. I did not heat the prop before applying the PropShield. Instead, I heated the PropShield by placing it in a tin immersed in boiling water.

 

[nimrod1230]

Interesting, my own experience was to use Method B ( No heat directly on the sterngear) after considerable effort to prepare the surfaces, as per the instructions. Launched 13th April. A few local trips in the Solent then down to Poole for a long weekend but performance under sail down by 15% and under power by 45/50%! Lift out on return on the 16th August to find the prop and shaft worse than ever before after 4 months! and 200Nm. On contacting PropShield they concluded that my preparation was inadequate and our mooring at the top of the Hamble river would be subject to lots of fresh water runoff containing nitrates in a wetter than normal year. I have to say that they did offer an FOC pot of PropShield but I have declined. My preparation was scrupulous and since August with just my normal application of waterproof grease things have been fine. Performance under both sail and power back to normal.

 

[pissativlypossed]

My experience of propshield is good. I applied it to my sterngear in February and on lifting out for a racing scrub last month all was clear other then a slight green slimey coating that cleaned off easily. There were no adearing barnacles, in contrast to last year.
I did burnish all the metal work with a powered wire brush and then heated it with a blow torch before application. Maybe this is the difference.

As metalurgist i am at a loss to explain why this should make a difference but i will be using propshield again this February.

 

[davidfox]

I used it for the first time last year, heated it up and slapped it on (april) out in Nov and not a trace of propshield on anything, yard had already jet washed by the time I saw it, but less hard fouling than normal it appeared, but I think it was not a particularily bad year for fouling, I will use it again this year as I have enough left over but jury out.

 

[nimrod1230]

Amazing, 399 views but only 6 users and these split 3 and 3 so no conclusions!

 

[BrendanS]

Why is that amazing? Just means few people are using it that have read the thread. Number of views does not equate to number of people that have read the thread, as many of us read the thread again each time a post is entered on the thread.

 

[ex-Gladys]

...and the main lesson is that fouling is very different in different places, even only several hundred yards apart. What works for one won't work ofr the same person elsewhere

 

[nimrod1230]

Oh dear BrendanS, I feel rather silly at being admonished in public.

 

[vyv_cox]

I for one have read it several times in the hope that someone could justify buying the stuff for me. I have applied hard racing A/F to my prop and shaft, the prop is bare of all paint within a week and the shaft fouls as quickly as it does unpainted. Anyone know how Prop Shield differs from any other hard or boot-topping A/F ?