How good is Prop Speed

[sunchaser]

Prop speeds effectiveness depends on actual prop speed.
I have been told, by several people including those that have a vested interest (prop and shaft engineers and applicators), that if your prop doesn't spin fast, prop speed is likely a waste of $$.

We have 4.52:1 reduction on our gearbox so on an 1150 rpm cruise we can almost count shaft rotation at 254 rpm.

At what prop RPM do your sources say prop speed is effective - i.e. keep growth off props? At 2:1 it works for us with several now and then bursts to around 2,000 engine RPM and a normal cruise of 1700 RPM.

 

[Simi 60]

At what prop RPM do your sources say prop speed is effective - i.e. keep growth off props? At 2:1 it works for us with several now and then bursts to around 2,000 engine RPM and a normal cruise of 1700 RPM.

I never bothered asking as I can't "magic" the extra rpm so no point

But I would think the vast majority of actual trawlers, like we were, are slow spinners and don't have prop speed.

I won't go as far as saying none of them do as I haven't seen them all, but I haven't actually seen one with it on.

 

[NEtrawler58]

Ok, you advise against Prop Speed but you have no experience with it..?

I have used Prop Speed on the prop, the rudder and the trim tabs. (all metal obviously)
It keeps growth off for 12 to 15 months with the boat being used once a week or more.
I have the yards apply it, prices have been different, from $400 to $700 or so.
(Single engine boat)

Nothing negative about Prop Speed, pricey perhaps but so is boating in general.
A boater on a budget can always jump in and scrape the prop a few times a month, no charge and a bargain..
(I did just that in my younger days when I was boat-poor and a live aboard.)

Sorry for the misunderstanding. I'm sure it's a great product. I didn't mean to say I don't recommend it, I meant that I didn't recommend it for this particular boater as he prefers to DIY and also appears to not have an unlimited budget. He seems to have little to no experience with bottom painting and I thought it might be a lot to handle for someone is just learning and trying different options. If you can afford to have it professionally applied I'm sure it's one of the best choices.

 

[NEtrawler58]

Anyone have any experience with Rust-Oleum cold steel galvanizing compound? I see it randomly get mentioned in threads here and there but I don't have an first hand experience with how it works. Rust-Oleum claims 93% zinc content. Could be a 4th option for OP.

https://www.rustoleum.com/product-c...s/stops-rust/cold-galvanizing-compound-spray/

I've used that on other underwater things (not attached to my boat) and it holds up well and doesn't accumulate any growth. I don't know for a fact, but others have claimed it is no different than the "Barnacle Barrier" paint just not labeled as such and therefore much less expensive. I would be inclined to give it a try.

 

[mvweebles]

Screen shot from a quick video a friend sent last year. Boat was towed to yard and hauled so prop never engaged. Boat had been sitting for a while obviously. The hard growth is easily wiped away by the gloved hand.

I wanna know why not prop-speed the entire boat, not just the running gear!

Peter

 

[NEtrawler58]

It would be prohibitively expensive. But Peter, you probably know this. Many sailboat racers rely on a slick finish instead of a biocide to limit growth on the hull. I once tried a Teflon-based paint on mine, but gave up as it was expensive and difficult to apply correctly. I'm guessing power boaters don't usually care about gaining an extra 1/10th of a knot as some sailors do. Otherwise I don't see why you couldn't use a racing-type paint on your hull if you wanted to.

 

[rslifkin]

It would be prohibitively expensive. But Peter, you probably know this. Many sailboat racers rely on a slick finish instead of a biocide to limit growth on the hull. I once tried a Teflon-based paint on mine, but gave up as it was expensive and difficult to apply correctly. I'm guessing power boaters don't usually care about gaining an extra 1/10th of a knot as some sailors do. Otherwise I don't see why you couldn't use a racing-type paint on your hull if you wanted to.

You absolutely could, but many of those paints aren't slick enough to keep slime and such from adhering unless you've got a fast boat that moves often (as they often have limited or no antifouling properties). The stuff scrubs off easily, but it still needs to be wiped off. So unless you're going to do like a serious racer and scrub the boat weekly, there's not much actual gain for a typical cruiser (power or sail).

 

[NEtrawler58]

You absolutely could, but many of those paints aren't slick enough to keep slime and such from adhering unless you've got a fast boat that moves often (as they often have limited or no antifouling properties). The stuff scrubs off easily, but it still needs to be wiped off. So unless you're going to do like a serious racer and scrub the boat weekly, there's not much actual gain for a typical cruiser (power or sail).

Good point, I forgot about the scrubbing requirement.

 

[mvweebles]

It would be prohibitively expensive. But Peter, you probably know this. Many sailboat racers rely on a slick finish instead of a biocide to limit growth on the hull. I once tried a Teflon-based paint on mine, but gave up as it was expensive and difficult to apply correctly. I'm guessing power boaters don't usually care about gaining an extra 1/10th of a knot as some sailors do. Otherwise I don't see why you couldn't use a racing-type paint on your hull if you wanted to.

I guess one of those great ideas in theory but impractical. Another being: why can't my seat on an airplane be made the same way as the Black Box that survives all catastrophies?

Peter

 

[Hippocampus]

Die hearts just pull their boats after each race. Worth more than a tenth even c/w a burnished hard paint.
What’s the reason prop manufacturers don’t apply a ceramic or other non stick coating? Understand make make balancing difficult but think should be doable.

 

[slowgoesit]

Anyone have any experience with Rust-Oleum cold steel galvanizing compound? I see it randomly get mentioned in threads here and there but I don't have an first hand experience with how it works. Rust-Oleum claims 93% zinc content. Could be a 4th option for OP.

https://www.rustoleum.com/product-c...s/stops-rust/cold-galvanizing-compound-spray/

I've used that on other underwater things (not attached to my boat) and it holds up well and doesn't accumulate any growth. I don't know for a fact, but others have claimed it is no different than the "Barnacle Barrier" paint just not labeled as such and therefore much less expensive. I would be inclined to give it a try.

At the recommendation of the yard, we had it put on the prop two months ago when we had the bottom done. We've run about 60 hours since, and you can see bronze through the paint at the tips now. We run at 7.5 kts (ish), and our prop turns about 650 to 700 rpm. I'd use it again. From the info on the can, and the MSDS, it appears to pretty much be the same as the more expensive "marine" zinc paints, but for half the price.

 

[NEtrawler58]

At the recommendation of the yard, we had it put on the prop two months ago when we had the bottom done. We've run about 60 hours since, and you can see bronze through the paint at the tips now. We run at 7.5 kts (ish), and our prop turns about 650 to 700 rpm. I'd use it again. From the info on the can, and the MSDS, it appears to pretty much be the same as the more expensive "marine" zinc paints, but for half the price.

I agree. I wouldn't be concerned about seeing some bronze at the tips after 60 hours. For some people, that's season's worth of hours. Do you know how many coats they applied?

 

[RedRascal]

Slowgoesit, thanks for sharing your experience on the Rust-Oleum zinc. Question, is your boat kept in salt, fresh or brackish water?

 

[slowgoesit]

I agree. I wouldn't be concerned about seeing some bronze at the tips after 60 hours. For some people, that's season's worth of hours. Do you know how many coats they applied?

Three coats of Rustoleum Zinc, sprayed on, with drying time between coats.

Slowgoesit, thanks for sharing your experience on the Rust-Oleum zinc. Question, is your boat kept in salt, fresh or brackish water?

Red, the boat is in Puget Sound, so salt water, although in our current marina, it is not as salty as the open ocean due to fresh water inflow from creeks/river.
Haulout was in January, we've put on about 70 hours since then. Plan on going to Alaska in late Spring, then SOC in Fall/early Winter. We'll see how it holds up!

 

[RedRascal]

Sounds like you have a nice cruise laid out to test the rust-oleum zinc. It looks great in the picture, looking forward to what you learn.

 

[NEtrawler58]

Three coats of Rustoleum Zinc, sprayed on, with drying time between coats.



Red, the boat is in Puget Sound, so salt water, although in our current marina, it is not as salty as the open ocean due to fresh water inflow from creeks/river.
Haulout was in January, we've put on about 70 hours since then. Plan on going to Alaska in late Spring, then SOC in Fall/early Winter. We'll see how it holds up!

Is that some sort of folding or variable pitch prop? I've never seen them other than on sailboats, but I don't know that much anyway. Always happy to learn more.

 

[lavida]

Propspeed after 2 seasons

I used to paint the bottom with antifoul and do the shafts and rudders with 2 coats of anti foul . My friend tells me Prop speed is the way to go .
Any thoughts ?

I had a boatyard apply Propspeed to my twin screws on my wooden displacement trawler. I did not pull out my boat for 2 years. There was excessive barnacle growth on the hull where I had applied std ablative paint. But the twin screws which were treated with Propspeed where incredibly clean. I have since tried spray on prop coatings and they fail miserably.

Propspeed Applied
https://images.squarespace-cdn.com/...HGQMSX2E/2013-05-14+09.18.23.jpg?format=2500w

Propspeed after 2+ Years in water
https://images.squarespace-cdn.com/...1N900WCTXOONLO6KQQ1/IMG_0440.JPG?format=2500w

Taken from Blog Post
https://www.thegreenboater.com/green-boater-blog/2022/3/11/propeller-coatings

 

[slowgoesit]

Is that some sort of folding or variable pitch prop? I've never seen them other than on sailboats, but I don't know that much anyway. Always happy to learn more.

It's a 36" Hundested CCP, or Controllable Pitch Propeller. Set the engine RPM to desired (and most economical RPM) then adjust Pitch lever for forward or reverse. Engine fuel control adjusts fuel flow to maintain selected RPM. Prop always rotates clockwise when viewed from the rear, and since you don't have to slow the engine down, shift to neutral, then into reverse, then bring rpm back up, you can go from full forward to full reverse in a matter of a few seconds! More common in working boats, or really high end pleasure boats. Expen$ive to buy and install, but the boat already had it installed!

 

[Peter B]

I used to paint the bottom with antifoul and do the shafts and rudders with 2 coats of anti foul . My friend tells me Prop speed is the way to go .
Any thoughts ?

It is good, but like those dangerous stunts you might see on TV, where they say."don't try this yourself", I would recommend a professional, used to applying it. It's costly if you muck it up - great if properly done.

Here's a pic of our boat at haul-out, before the pressure wash, and after 3 years in the water after Propspeed to propellor only, and not touched by any diver in that time.

Oh, wow - I've just seen the links from lavida above, post 47, and they trump mine like a lay down misère...and I thought my results were good..?

 

[mvweebles]

Riva 59 Mercurius with twin MAN 1050 hp engines in Ensenada . Crazy pitch on these props! Yard tells me they go through a dozen mid-quality brushes when applying prop-speed to assure brush stays pliable.

Peter

 

[NEtrawler58]

I had a boatyard apply Propspeed to my twin screws on my wooden displacement trawler. I did not pull out my boat for 2 years. There was excessive barnacle growth on the hull where I had applied std ablative paint. But the twin screws which were treated with Propspeed where incredibly clean. I have since tried spray on prop coatings and they fail miserably.

Trying to paint or spray over top of propspeed could be the problem. If I had such good performance after 2 years, I would have stayed with it. Was it just a matter of cost that made you try something else?

 

[maggiecat1003]

Related question to all this as I started scraping barnacles on metal underneath this weekend.

What is the best way to remove multiple excess layers of bottom paint from the rudders and the shaft struts? I want to get these parts to bare metal. The stuff is hard like a rock.

 

[rslifkin]

I stripped mine a couple years ago. Just sanded the paint off. Orbital sander with a vacuum hook up and 80 grit discs is slow, but fairly neat. I switched to a rotary sander that was much faster, but even with vacuum, harder to contain the dust. Even with finer grit discs the rotary sander was very fast compared to the orbital (need to be careful not to dig into metal).

 

[NEtrawler58]

Related question to all this as I started scraping barnacles on metal underneath this weekend.

What is the best way to remove multiple excess layers of bottom paint from the rudders and the shaft struts? I want to get these parts to bare metal. The stuff is hard like a rock.

The BEST way is to pay someone to do it! (only half-kidding). Before you decide how to do it and begin sanding or anything else, if your boat is stored in a marina check with them first. They have very strict environmental regulations on what they will allow to be done on their property.

 

[maggiecat1003]

Related metal parts

Related to all the above I am curious as to how to prep and which paint selection for each for all of the metal parts I have photos attached? It is confusing as there is a lot of different parts underneath. I am happy overall with the status of bottom as it was our first year/attempt. I plan to rough sand bottom and pay attention to bare spots and a good coat on everything.

Transducers which appear to be brass 2 round with one on each side. One oblong on starboard side.
Strainers which are metal but I don't know what and no external bolts to remove. Last year I cleaned all calcium carbonate off and cleared strainer holes
Shaft struts
Trim tabs

I am clear on the propellers and will use a zinc coating after they come back from shop.

 

[NEtrawler58]

Hi again Maggie. I'm not sure there is an exact science on this. Lots of products and even more opinions. What I do persoanlly is clean/scrape/wire-brush all the underwater metal thru-hulls and strainers and spray them with zinc paint. (Wire brush wheel on a drill works great). Then paint over them with the same bottom paint I use on the hull. There are specific transducer paints that are recommended, but I've never had an issue using regular bottom paint.

 

[Fletcher500]

I am hauling out in 2 weeks. Prop Speed for the underwater metals, except the Prop. I find after about 9 months the prop gets a bit rough even with frequent cleanings, and I like to keep my prop very smooth especially during the Summer when I am putting on the miles. I therefore use some wet/dry finer grit sandpaper on the prop periodically.

 

[Hippocampus]

Anybody ever use lanolin?

 

[Island Cessna]

Anybody ever use lanolin?

I used lanolin on my plastic bow thruster prop. After 2 years no barnacles or hard buildup. I assume diver hand cleaned it at the 1 year mark when he changed the zinc. Re-applied it a year ago, no sign of deteriorated performance yet.

I use Prop Speed on the main prop. The bow thruster operates a minute fraction of the time.

Bill

 

[BruceK]

Anybody ever use lanolin?

Our sheep will thank you if you do, lanolin comes from sheep`s wool. Baaaaa..