Folding or fixed prop?

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Travelling Westerly

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This question might seem a bit backward but here goes anyway;

I have a Volvo 3 blade folding prop fitted at present. It was only put on a year and a half ago (brand new) and quite frankly I hate the the thing! It makes a horrendous grunching (if thats a word) noise when I select astern and the only way to get rid of the noise is to rev the engine up, wait for the noise to disappear before reducing revs. I assume its prop clatter at low astern speed. Pepole in the marina look over thinking something is knackered on my boat. It sure sounds like it! It was so expensive and I cant believe I actually brought it!

I have a nice Radice fixed 3 blade prop as a standby and I am thinking of fitting this when she comes out next.

Pros and Cons below as I see it;
Folding prop Pros - lower drag when sailing, no to very little prop walk. Cons - clunky and bloody noisey
Fixed prop Pros - no noise. Cons - more drag when sailing and prop walk.

Am I mad going backwards in fitting a fixed prop?
 
yup, mad indeed! The Volvo three blade does not make any noise, or at least the one we had for eight years did not. admiitedly I have always tended to pause in neutral for a second before engaging reverse but that is because I am a cheapskate who reckons being kind to machinery pays back in longevity.
Take it back and get it sorted, you don't want to be dragging a sea anchor around unless you always motor.

PS We have currently got a £2k Flexofold 3 blade folder, nicely made but I think the VP was better designed except for the miserable wee anodes.
 
Better than folding or fixed is feathering. I have a MaxProp which works brilliantly. Not only does it feather effectively for sailing, but it 'reverses' when going astern, so backwards works just as well as forwards. It's a revelation. But uncheap, obviously.
 
Quandary said:
yup, mad indeed! The Volvo three blade does not make any noise, or at least the one we had for eight years did not. admiitedly I have always tended to pause in neutral for a second before engaging reverse but that is because I am a cheapskate who reckons being kind to machinery pays back in longevity.
Take it back and get it sorted, you don't want to be dragging a sea anchor around unless you always motor.

PS We have currently got a £2k Flexofold 3 blade folder, nicely made but I think the VP was better designed except for the miserable wee anodes.
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Its fine in forward and makes no noise other than the intial opening clunk but going astern its horrible! Spoke to the dealer who just said give it more throttle to get it fully open when going astern. I think the clatter is it partially opening/closing rapidly when on tickover going astern? Happy to be corrected on that but Im not sure what there is in way of getting it sorted? It would be great to have it make no noise.
Luckily my prop does'nt have any anodes so at least Im not giving VP any more money on this thing
 
papaver said:
Better than folding or fixed is feathering. I have a MaxProp which works brilliantly. Not only does it feather effectively for sailing, but it 'reverses' when going astern, so backwards works just as well as forwards. It's a revelation. But uncheap, obviously.
Click to expand...
Argh - wish Id brought one of those first :(
 
Fixed prop= motorsailer.
Feathering prop is a nice option, but folding props are less likely to catch lobster pots.
A lot of dosh to avoid making a bit of noise for a few seconds now and then when selecting astern in a marina.
Our folding prop does not 'grunch'. It would be good to understand exactly what's going on with yours?
 
Are you sure you have a Volvo three blade folding prop? The absence of the collar anodes is very strange, the VP design has had them for the last 15 years or so and as far as I know even before that. Heavy bronze boss with ring of zinc anodes and nylon buffers, hockey stick shaped blades? If there are no anodes perhaps your pivot pins have worn larger or oval holes in the bronze and your blades are rattling about.
A good engineering shop can bore out the holes and turn oversize pins for you for a lot less than a new prop. just make sure they use the right grade of stainless steel, but make sure the unprotected bronze has not gone pink before spending money on it.
 
Quandary said:
A good engineering shop can bore out the holes and turn oversize pins for you for a lot less than a new prop. just make sure they use the right grade of stainless steel, but make sure the unprotected bronze has not gone pink before spending money on it.
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Can bronze go pink?

My two folders do not make any more noise than the previous fixed props.

Richard
 
My boats got a Volvo folding three blade prop - never had any noise at any speed forward or reverse - agree with Quandary are you sure it's a Volvo as all the one's I've seen have ring anodes on the boss.
 
If it runs smoothly in ahead but graunches in astern until you rev it up it sounds as though it is out of balance in that state - in other words one blade isn't conforming to the others but eventually is beaten into submission by the extra revs.
Sounds tome as though it needs a close examination for correct functioning and freedom of movement of the blades.
 
RichardS said:
Can bronze go pink?
Richard
Click to expand...

Pinkish! My prop died last year. It has been ringing quite brightly for 8 of the 10 years that I have owned the boat, then, last year, at a 10 year insurance survey, a small bit on the tip just broke off as the surveyor poked it, the propellor also rung dull. Not sure why all of a sudden it has turned pink but the time before it was out the water it was not like this. I have bought one of these carbon brush devices that connects to the propellor shaft and the anode.

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr
 
BlowingOldBoots said:
Pinkish! My prop died last year. It has been ringing quite brightly for 8 of the 10 years that I have owned the boat, then, last year, at a 10 year insurance survey, a small bit on the tip just broke off as the surveyor poked it, the propellor also rung dull. Not sure why all of a sudden it has turned pink but the time before it was out the water it was not like this. I have bought one of these carbon brush devices that connects to the propellor shaft and the anode.

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr
Click to expand...

I thought that bronze and DZR brass were the "gold standards" for marine use because the amount of zinc in them is below that needed for de-zincification?

Richard
 
BlowingOldBoots said:
Pinkish! My prop died last year. It has been ringing quite brightly for 8 of the 10 years that I have owned the boat, then, last year, at a 10 year insurance survey, a small bit on the tip just broke off as the surveyor poked it, the propellor also rung dull. Not sure why all of a sudden it has turned pink but the time before it was out the water it was not like this. I have bought one of these carbon brush devices that connects to the propellor shaft and the anode.

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr

Untitled by Rival Sailor, on Flickr
Click to expand...
Looks very much like dezincification, it follows that the prop is manganese bronze, a 60/40 brass with minor additions.

Dezincification is a form of selective corrosion, in which one phase is anodic to the other and corrodes preferentially. Up to about 35% zinc, brass is single phase, known as alpha. But this is ductile with no great strength. Higher levels of zinc introduce a beta phase, zinc rich. In dezincification it is this phase that is lost. DZR is cleverly designed to be single phase, about 37%, but still have good strength. It also contains 0.1% arsenic, which provides corrosion resistance.

Bronze has a small zinc content as a deoxidiser. Oxides are a big problem in bronze castings as they mix with the molten metal, creating weakness. Bronzes do not suffer dezincification.

Anodes provide little protection for dezincification, basically zinc trying to protect a zinc-rich phase. The anode is used to delay galvanic corrosion between the prop and the shaft.
 
A couple of points.

First, I too have a three blade folding VP prop on a saildrive and have never had any problem such as described bu the OP. This is on a D1-30 engine but it was previously fitted to a 2030.

Second, I too thought they all had the silly little anodes which do not last a year on my boat. However, another post some weeks back talked of a Volvo folder without these anodes, and when I queried it, the post was correct and referred to a prop for a larger engine. It would be useful to know the engine and boat size, and whether it's on a saildrive or a shaft.
 
richardbrennan said:
A couple of points.

First, I too have a three blade folding VP prop on a saildrive and have never had any problem such as described bu the OP. This is on a D1-30 engine but it was previously fitted to a 2030.

Second, I too thought they all had the silly little anodes which do not last a year on my boat. However, another post some weeks back talked of a Volvo folder without these anodes, and when I queried it, the post was correct and referred to a prop for a larger engine. It would be useful to know the engine and boat size, and whether it's on a saildrive or a shaft.
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It was probably my post lol. Its a VP 3 blade fitted for me brand new along with a brand new D2 50 and gear box from FYB (a VP agent). Its possibly the largest model and does not have any anodes nor the ability to fit any. As you spotted the VP brochure shows this. Apparently corrosion is not an issue due to make up of bronze type.

Boat is 40ft on a shaft. Basically new engine, gearbox and prop all at the same time.

Its only run 38 hours from new so nothing should be worn yet. The noise reminds me of when you mess a gear change up on a car.
 
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