10 Diameter Bronze Prop - how heavy?

[pcolaboy]

10' Diameter Bronze Prop - how heavy?

Can anyone take a stab at the weight of a 10' diameter, three-bladed, bronze prop? Are giant lift-bags even an option to move this thing? We are only wanting to relocate it temporarily so we were trying to devise a plan to partially float it and tow to a new temporary home next to my partner's dock. Previous tug-owner gave us the location of it and said that it's ours if we want it. Only details I can give is that its covered with years and years of barnacles, oysters, soft corals, etc. and is laying on a very shallow sandy bottom. A large pusher tug had a mishap where the shaft was sheared off depositing this prop onto the bottom back in the 60's.

Thanks in advance,

Pcolaboy

 

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[thepirate]

Re: 10' Diameter Bronze Prop - how heavy?

Hi Pcolaboy - I've got a table with weight profiles.

An 8' Bronze 3 bladed prop weighs in at 2650 lbs plus 8% - so 2862 lbs. There is a formula for weight which applies to a 3 bladed , bronze prop of 20% hub diameter and .33 mean width ratio. Weights for similar props increase at just over the cube of the increase in their diameter so a 10' prop would weigh in at well over 4100 lbs.

Hope this is of use , Mike.

 

[paddy.mick]

Re: 10' Diameter Bronze Prop - how heavy?

Wow! so a little more than 5, 100gallon lift bags could work, but you'd need a surface supply air for sure! Good luck with it, sounds better than can collecting.
Paddy

 

[Smokin Joe]

Re: 10' Diameter Bronze Prop - how heavy?

Last I heard, it was about 3 bucks a pound, too.

 

[Ascholten]

Re: 10' Diameter Bronze Prop - how heavy?

brass is a buck a pound maybe 1.25 IF you are lucky....

probably a few tons it weighs...

instead of scrapping it, if it's not too tore up, you might be able to sell it.

given it was involved in a shear accident it's probably tore up...... gonna take a bit to raise this thing, all them barnicles and such add weight, not to mention the oysters etc the water they hold in them adding too. If you are going to lift it, might want to set a small charge under it, tannerite possibly to bust it loose from the crud holding it down / in place, then lifting it up a bit lighter.

good luck

aaron

 

[vintagesailor]

Re: 10' Diameter Bronze Prop - how heavy?

If you do pull it up, I would be interested in getting some of that bronze. Just enough to make a couple pop guns

 

[Voldbjerg]

Re: 10' Diameter Bronze Prop - how heavy?

given it was involved in a shear accident it's probably tore up...... gonna take a bit to raise this thing, all them barnicles and such add weight, not to mention the oysters etc the water they hold in them adding too.

I dont think barnacles and oysters can live on the prop. Too high a copper content is toxic for them.

/V

 

[thepirate]

Re: 10' Diameter Bronze Prop - how heavy?

Sounds like fun though - let us know how it works out..with pics if poss.

 

[ScottyLee]

Re: 10' Diameter Bronze Prop - how heavy?

lol....it only takes a couple of weeks for barnacles to grow on a prop in south Fl.

 

[stevemc]

Re: 10' Diameter Bronze Prop - how heavy?

I was thinking bronze is $2-$3 per pound. I remember a 1930s steamer(Bayronto) that went down here, and no one salvaged the prop as it was way too heavy. A guy finally did and kept it for years, and I think finally sold it. It wasnt 10' diameter, but the hub was real big. It had detachable blades on a big hub. It looked like it weighed more than 2 tons though. Maybe not. So be prepared to bring more bags.

 

[FISHEYE]

Re: 10' Diameter Bronze Prop - how heavy?

Im going to the scrap yard today to get rid of over 50lbs of nice clean pure bronze,ill let you all know what the current scrap price is for it.in sebastian it takes less than a week for barneys to grow on my bronze props.im about tired of cleaning them so im building a new device to install next week.it will take some a few weeks for some adjustments.barneys wont grow anywhere on my boat when im done.

 

[stevemc]

Re: 10' Diameter Bronze Prop - how heavy?

Fisheye, are planning on putting one of those "barnacle knocker" things? Where you put 6 transducers on the inside of the hull with epoxy? Or did they stop making them? I used to be a boat rigger and the only way those worked, was with a newly painted bottom . Maybe they have improved them. Barnacles do grow quick! I used to clean boat bottoms, and on the props and rudders and the scum line, every month they would be big enough to cut your knuckles real good if you didnt wear leather gloves. From experience of course! I always thought that a good way to keep barnacles off your prop, would be to heat it up, flux it and then dip it into hot lead. I know it wouldnt be EPA approved but it should keep the prop clean. And last a heck of a lot longer than bottom paint-it doesnt last at all on a prop. tell us about your barnacle plan. Steve.

 

[FISHEYE]

Re: 10' Diameter Bronze Prop - how heavy?

stevemc,

Im not going with the transducers as of yet.have thought about it.a company in jax florida makes a product called barnaclean.they are transducers much like low profile speaker tweeters.i have a copy of thier patent.all they do is vibrate the hull in a 2 x 2 foot area where they are attached.barneys wont grow if the surface they want to attach to is moving or vibrating.the barnaclean uses a certain sound frequency that wasnt disclosed in thier patent.i would imagine its a low freqto cause the hull to vibrate.much like the rumbling effect the movie producers did for the movie "earthquake"there are other ways to do thislike mechanically useing 12 volt vibrating motors.thats what im trying right now.i doplan on re doing the bottom of my boat.stripping it all down to the bare aluminium.a few coats of epoxy dupont corlar.($100 a gallon)a few coats of epoxy alumagrip($250 a gallon)and a few coats of ameron ABC epoxy antifouling paint(havent got a price yet on gallons)and this new antifouling clear paint for the bronze props,its called prop clear.with the ameron ABC no barneys will grow for 6 years.4 on the propclear paint.so before i pull the boat out the vibrators will have to keep me an my crew from going in the water to scrape barneys.i have 2 12 motors now.just going to scrape the stern an epoxy them to the inside of the hull with a reostat on them set at #1 for a week.if nothing grows in a week then thats the setting to use.if they grow they get scraped off then on to the next setting.ill keep upping it till theres no growth.an if it works then ill get more motors an put them every 2 foot square around the inside of the hull and also on the shaft and rudder mounts.the motors are cheap like 2 bux each.the barnaclean system sells for around $1000 for 10 transducers to do my boat.they have a money back 1 year warranty on it.

 

[stevemc]

Re: 10' Diameter Bronze Prop - how heavy?

The kind I have put in were called " Barnacle Busters". They had little pucks that would make a fairly quiet knocking sound, like you were underneath a depth sounder transducer, but like a couple a second. I have only seen it on freshly painted boats, and I have heard that it doesnt work, but that was 25+ years ago, and they are still being sold so.... We'll see. Good luck with this project!

 

[Ascholten]

Re: 10' Diameter Bronze Prop - how heavy?

buy a trailer and keep the boat out of the water, barnacle problem solved.

Other than that there are 'knockers', 'squeakers', and cathodic protection devices, each has it's pros and con's, some work some dont.

The best place to find out about a particular device is probably one of the online boating forums. Id have to recommend against any specific products webpage as you know they are going to tell you it's the best thing since sliced bread because they are trying to peddle one off to you.
Aaron

 

[FISHEYE]

Re: 10' Diameter Bronze Prop - how heavy?

Ascholten,

No one makes a trailer big enough for my ship,even if they did i would need a mac truck to pull it.it stays in the water all the time.i have already done my research and know what to do for my aluminium ship.

 

[Ascholten]

Re: 10' Diameter Bronze Prop - how heavy?

Aluminum ship? talk to anheuser busch, see what they line their aluminum beer cans with, and score a couple of drums of that and paint yer boat with it. Maybe offer to put some kind of bud advertisement on the ship and they'd pay you for it. Or better yet, as corrosive as coca cola is, ask them, while it's probably the same stuff, it seems to work rather well.

Aaron

 

[FISHEYE]

Re: 10' Diameter Bronze Prop - how heavy?

they dont line thier cans with anything,i see enough of them in salt water where theres nothing left of them,besides i hate anheuser busch products an dont drink coke.my ship is made out of a non corroding marine aluminium.you can only put paint on it that doesnt contain lead or copper.

 

[stevemc]

Re: 10' Diameter Bronze Prop - how heavy?

Fish eye, keep an eye on those zincs. Even though you have a special aluminum, it will corrode if the zincs are gone. Aluminum boats are fairly tough, but that is their main weak point. But they are extremely light, so the fuel mileage is better than a wood or fiberglass boat.

 

[FISHEYE]

Re: 10' Diameter Bronze Prop - how heavy?

I have plenty of zincs.and they are all in good shape,just replaced one of the shaft zincs.plus i hang the fish looking zinc off the stern thats grounded to the metal.it picks up stray electric current from other boats leaking it from thier shore power.at the moment im not hooked up for shore power.have to rewire the connector for it.my ship weighs 14,000 lbs dry.i can go 130 miles an only burn 25 gallons of diesel running at 12 knots.