Cleaned the propeller - gained 40% more speed

westernman

westernman

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I dived under the boat and scraped some crud off the propeller while anchored in a nice bay the day before yesterday. This improved my top speed from 5.4 knots to 7.4 knots. Just for reference, I am 45ft LWL, 32 tons and have an 85hp engine (not exactly over powered).

If I get the propeller really clean, and clean the hull a bit, I should be able to get back to my 7.6 knots under power. I was worried that I might have a problem with the turbo charger - but just a bit of shell fish on the propeller was all it took for such a big difference.
 
Not surprised. In places like SoF and Palma we have lost 5-6kts of boat speed in just 2-3 months over spring and summer solely due to sterngear fouling. In fact there was one occasion after a few months of not using the boat in Palma when the boat wouldn't actually plane due to sterngear fouling. After that I used to have my sterngear cleaned by a diver at least 3 times a season
 
Not just SoF I'm afraid. Rafiki lost 10 knots in warm July's in 2014 and this year in Portishead Marina. Tube worm casts on the stern gear. Took a bit of scraping too.
 
michaelchapman said:
I dived under the boat and scraped some crud off the propeller while anchored in a nice bay the day before yesterday. This improved my top speed from 5.4 knots to 7.4 knots. Just for reference, I am 45ft LWL, 32 tons and have an 85hp engine (not exactly over powered).

If I get the propeller really clean, and clean the hull a bit, I should be able to get back to my 7.6 knots under power. I was worried that I might have a problem with the turbo charger - but just a bit of shell fish on the propeller was all it took for such a big difference.
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Very helpful thanks, I thought I noticed I'd lost a knot and a half under power over the 7 week cruise, looking from the deck the prop looked clean but with white discolouration, I suspect now I had small crustacean crud and wished I'd cleaned it before the 250 mile journey home!
 
michaelchapman said:
Anything efficacious for putting on propellers? Some kind of non erodable antifoul?
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with the danger of turning the thread to "what antifoul for sterngear" I can assure you that MiToS wont plane after 2months in the water... Water temp is 28+
This time I used TK propeller spray. Went through all the trouble, read the instructions, cleaned carefully the propellers (aqua forte, heat/scrape, soft foamy disk on a small angle grinder, careful caressing, talking gently, whatever) then 4 or 5 coats of the bloody thing and I can confirm that it was 20euro down the drain.
4weeks later it was full of this tube worm thing :(

Got the son and his g/f to clean the propellers did a so and so job of it, not easy but I haven't tried pushing again as I was in company with a diesel bug infested P45 and we were at 8-9kn everywhere.

However, I used the other special a/f for metals for the trimtabs and I'm amazed that it's still intact and alone with no vegetation. Next year I'll try that on the props... Sorry name escapes right now, is in small 200ml? cans, primer is yellowish, a/f is either white or black.

EDIT: the trimtab a/f I'm talking about was on the Underside of tabs, ie. where they get a good beating!
Further, this a/f was recommended by a guy servicing and maintaining rental sailing yachts for props. I understand that yacht props turn at lower speed to planning hull props, so if it works in the Aegean I cannot imagine not being worth trying in SoF. Have the pots at the boat, will post the name later.

V.
 
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Can confirm my Surface Drive P54 wouldn't get on the plane after sitting idle in the water over winter/spring. Having a diver cleaned the prop/gear solved that although I still lost some speed (5-10 knots) from the not having a clean hull. After lifting and new anti foul applied and again cleaning of props/gear I reached 46 knots a few weeks back which I though not bad for 12 year old boat.
 
vas said:
with the danger of turning the thread to "what antifoul for sterngear" I can assure you that MiToS wont plane after 2months in the water... Water temp is 28+
This time I used TK propeller spray. Went through all the trouble, read the instructions, cleaned carefully the propellers (aqua forte, heat/scrape, soft foamy disk on a small angle grinder, careful caressing, talking gently, whatever) then 4 or 5 coats of the bloody thing and I can confirm that it was 20euro down the drain.
4weeks later it was full of this tube worm thing :(

Got the son and his g/f to clean the propellers did a so and so job of it, not easy but I haven't tried pushing again as I was in company with a diesel bug infested P45 and we were at 8-9kn everywhere.

However, I used the other special a/f for metals for the trimtabs and I'm amazed that it's still intact and alone with no vegetation. Next year I'll try that on the props... Sorry name escapes right now, is in small 200ml? cans, primer is yellowish, a/f is either white or black.

EDIT: the trimtab a/f I'm talking about was on the Underside of tabs, ie. where they get a good beating!
Further, this a/f was recommended by a guy servicing and maintaining rental sailing yachts for props. I understand that yacht props turn at lower speed to planning hull props, so if it works in the Aegean I cannot imagine not being worth trying in SoF. Have the pots at the boat, will post the name later.

V.
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Yep, can confirm that tube worms have a liking for the TK a/f. Vas, when you get a moment, can you post the name of the useful a/f please?
 
vas said:
However, I used the other special a/f for metals for the trimtabs and I'm amazed that it's still intact and alone with no vegetation. Next year I'll try that on the props... Sorry name escapes right now, is in small 200ml? cans, primer is yellowish, a/f is either white or black.

EDIT: the trimtab a/f I'm talking about was on the Underside of tabs, ie. where they get a good beating!
Further, this a/f was recommended by a guy servicing and maintaining rental sailing yachts for props. I understand that yacht props turn at lower speed to planning hull props, so if it works in the Aegean I cannot imagine not being worth trying in SoF. Have the pots at the boat, will post the name later.

V.
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I'm guessing you mean Velox Plus, or there are a couple of equivalents by other manufacturers. Velox is the only thing which has come close to working for me, as it did last a whole season on my props, and was largely intact at lift out the following spring.

I asked the yard to do it again, but they used an equivalent and i'm not sure the prep was as good, so it didn't work nearly as well, in fact no better than Trilux, which stops fouling for a bit then wears or falls off.

I may have another go with it, but prepare the props really thoroughly and apply it myself to see if I can repeat the success.

As i'm sure you realise, trim tabs are no comparison, they have an extremely easy life compared to the props
 
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I wonder if it's possible to get aquacote to adhere to the sterngear? Looks impressive on the video I saw, where the guy was able to easily wipe off the slime (but not the antifoul which still looked new) off the hull with his hand.

Edit: Just looked at their site and they do an Aquacote Prop product, anybody tried it?
 
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Nick_H said:
I'm guessing you mean Velox Plus, or there are a couple of equivalents by other manufacturers. Velox is the only thing which has come close to working for me, as it did last a whole season on my props, and was largely intact at lift out the following spring.
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yep! that's the one Nick. Yes, it's produced by a few companies as well, but it's the same thing.

Nick_H said:
I may have another go with it, but prepare the props really thoroughly and apply it myself to see if I can repeat the success.
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yes, I'd give it another go, they are generally v. strict on preparation, do it properly and see how it performs.
Actually, it's not a matter of performance but staying on...
Nick_H said:
As i'm sure you realise, trim tabs are no comparison, they have an extremely easy life compared to the props
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yep, but I also know that my last year attempt only lasted 1nm on the tabs :D
This has lasted 300nm, that's progress!

cheers

V.
 
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