Stainless Steel Props....

[Ripster]

Who has changed their prop to stainless and why? I have got a perfectly good ally 3 blade on a Bravo II and have been "advised" to get a stainless 3 or even 4 blade replacement. On the like for like replacement 3 for 3 will the stainless prop make any diff to anything performance-wise or fuel econ-wise.

I know a 4 is supposed to be smoother and faster out of the hole, but limits top end due to resistence....etc...etc...

Anyway - any advice on this?

 

[MapisM]

So, you have something which is "perfectly good" and someone advised you to replace it with something else. /forums/images/graemlins/confused.gif
Trust me, a composite one is what you really need! See, I've got one for sale right now... /forums/images/graemlins/grin.gif

 

[BartW]

A year ago I read a comparison test in a German magazine,
and the result was that there was no real advantage for SS.
In some cases the SS had 1 or 2kn more top speed (do you care for 2kn ?)
but In some cases the SS was not as good as the Alu (depending on prop shape and make).
So the SS are not worth the extra money IMHO.
I have been adviced and have experienced myself that a alu merc prop or Vortex oem made are the best props you can get for a merc drive, as long they are in top shape, not damaged or bend,
performance goes down even with a scratch
cheers
Bart /forums/images/graemlins/ooo.gif

 

[Bandit]

Sometimes you get better top speed with ss props, you should get less cavitation erosion to the blade roots with an ss only if this is already an issue with the aly, on some diesels 300hp Volvo Penta there were issues with blades on aly props snapping off so changed to ss.

Ss is eminently more nickable

The two big down sides of ss props are electrolytic corrosion with the leg and anodes and if you hit something an aly prop is more likely to bend and protect the drive train whereas an ss prop is more rigid and will send the damage into the gearbox, fusible link or drive shaft which is mucho expensivo.

IF no reason to change dont.

 

[landlockedpirate]

I have a bit of a fetish for props, my boat came with a 3 blade ali as standard. Soon after I bought a 3 blade stainless and a 4 blade ali one. The truth is I can see very little difference between them, but stainless one does look a lot nicer when the boats on the trailer /forums/images/graemlins/grin.gif

 

[DavidJ]

When I bought my Sealine with KAD43's, Sealine (God bless'um) supplied me with SS props. Apparently there was a problem with the coating coming off the Al props (due to deflection) on the more powerful KAD44's hence their general change to SS.

 

[geardownthreegreens]

I would never never ever touch another plastic /composite prop again.
I bought one for my first boat which had adjustable blades.
After a few months the boat was suffering from serious vibration and not even 2 boat engineers knew what the problem was even after the leg had been stripped.Sold the boat as is eventually.

I can vouch for the high five stainless prop.Really really good performance allround, you wont regret it.

 

[geardownthreegreens]

[quote

Ss is eminently more nickabwith

Tell me about it. I had my brand new high five prop stolen after 2 weeks.Bought it brand new £400
I will be buying another when i can afford it as the current ss laser 2 is crap in my opinion. Nowhere near in the same league.

 

[Elessar]

The theory is stainless props can be thinner and so offer less "egg beater" resistance. Don't know if it's true in practice.

They are certainly stronger, a light contact with silt doesn't damage a stainless prop but badly deforms an ally one.

Ally props are much cheaper to repair however.

If you do have a corrosion problem ally props will sacrifice themselves before your out drive has to.

As to 4 blades - it will be less efficient as you have 4 leading edges causing egg beater drag. A one bladed prop is the most efficient, shame it's not possible to balance it.........

 

[PowerYachtBlog]

I changed from alloy to Solas ss (not volvo) on my previous boat 2 x 200hp Volvo Diesels

the advantage I got was lower planning speed about 1 knot less, no vibration at low speeds, and steadier speeds on cruising with movement -1 knots in following seas, with alloy this used to be 2 knots on average

top speed decreased by 1 knot, but may be I could have gone for a pitch bigger with ss
my new boat has alloys twin KAD43 and I will stay with them I think... they offered me good prised SS last week, so I might buy them and keep them spare