Performance stainless props?

[Devonmark35]

Hi guys

Stainless props - do you think they are worth the extera money or not? A Chap on board has told me that stainless props are'nt really worth the extra money and if I hit an object with the prop then more damage can occur to the engine/G Box as the stainless will tansmit more shock/energy into the leg as opposed to an alloy one just breaking or bending. I can see his point and looking at the leading edges of my prop it looks like I might need a new one soon (slight errosion). I have a standard Mercury 2004 50 EFI and am happy with the performance with 2 up but when I load up (3 people with kit) the 4m Avon does tend to take a while to get going. Can anybody recommend a good replacement prop or should I just stick with what I have?

I used to jet ski when I was a kid and the first thing to increase performance was to change props to stainless with a progressive pitch etc - is this the case with boat props?

Just to make matters difficult I'm away at the moment and dont know what size/pitch etc the old one is - other than its as brought when new (that probably does not help sorry)

Thanks

Mark

[Hightower]

Your friend is right about stainless props being more likely to damage the gearbox should you impact something.

If you're happy with general performance then I wouldn't bother. There are performance advantages, but with such a small RIB and outboard you're not likely to see anything significant and almost defiantly feel cheated of some money vers. performance gains. Much better to re-invest in another alloy prop, perhaps with an inch or so smaller pitch to allow you to swap props dependant on loads, weather conditions and what you're doing.

[HUMBER P4VWL]

Id agree, we ran a SR 5.4 with a 90opti with ally props for 10 years, safer if you hit a rock, your gearbox will hopefully be fine. Not worth the extra money IMHO

With larger engines, we put an ally on our 175 opti, it didnt like it. So much power and it kept cavitating, even tried a variety of pitches etc, but the strength of the stainless comes in to its own. They use rubber mounts so that if you do hit a rock, it should protect the gearbox.

[Devonmark35]

Andy & Paul

Thanks - thats made me decide to keep what I've got & buy a direct replacement when its worn out.

Many thanks

Mark

[ashbypower]

Originally Posted by Devonmark35

Andy & Paul

Thanks - thats made me decide to keep what I've got & buy a direct replacement when its worn out.

Many thanks

Mark

Why not have it Reworked/paired? fraction of new price aswell THESE guy's are hard to beat and great service

[Devonmark35]

Originally Posted by ashbypower

Why not have it Reworked/paired? fraction of new price aswell THESE guy's are hard to beat and great service

Nice one Brian

You may have saved me some money there - thanks

[Hightower]

Might I suggest having two props, the one not being used, use for a spare for immediate use. With two different pitches you can use the RIB to best effect both fully laden or by yourself. Will only cost you the cost of a repair and another prop. Should be able to pick a prop up cheap enough on ebay

[Devonmark35]

Yep good idea Andy.

Any suggestions of what I should look out for - 3/4 people load, not too worried about top end just a good bit torque/grunt (if thats the right word)

Cheers

[Portholme]

Hi

following advice from this forum and some prudent bidding on ebay I got an unused 13" pitch prop for mine to replace a 14" for just over £60.

zodiac 480 with 60horse Mariner. Usually well loaded with kids/wife and struggled to get up and go when uber loaded. With new prop it has much better pick up. Interestingly i rubbed down and resprayed the old prop and that is miles better too. the corrosion was clearly impeding performance (not suprising really).

[Bigmuz7]

There is always the risk from hitting something with a stainless prop, but its more efficient because its thinner, so performance is enhanced .. whether you get that from that size of rig is another matter .. but IMO its always worth having and will save you a few quid on petrol .. eventually ... !

I also prefer their 'Bite', faster pick up, etc

[Turbodiesel]

I think Stainless props make a difference, spent many years testing props back to back. Also Stainless props have hub kits that are designed to break if you hit something, so you dont see that many gearbox problems. I have seen loads of twisted prop shafts on ally props without hub kits! As far as getting better performance when loaded you should look at 4 blade props, they do make a difference with a loaded up boat.

[Devonmark35]

Originally Posted by Turbodiesel

I think Stainless props make a difference, spent many years testing props back to back. Also Stainless props have hub kits that are designed to break if you hit something, so you dont see that many gearbox problems. I have seen loads of twisted prop shafts on ally props without hub kits! As far as getting better performance when loaded you should look at 4 blade props, they do make a difference with a loaded up boat.

Cheers Rob

Its comming down to you for the service as soon as I get home so we can discuss then. Thanks

Mark

[piranha580]

Originally Posted by Turbodiesel

I think Stainless props make a difference, spent many years testing props back to back. Also Stainless props have hub kits that are designed to break if you hit something, so you dont see that many gearbox problems. I have seen loads of twisted prop shafts on ally props without hub kits! As far as getting better performance when loaded you should look at 4 blade props, they do make a difference with a loaded up boat.

Is there a big difference between a 3 and a 4 blade prop? I'm toting with the idea of getting a different pitch prop at the mo for some better pick up.. But I also see there's a choice of a 3 or 4 blade too! Would you lose out on top end with a 4 blade??
Cheers
Mark

[Turbodiesel]

Originally Posted by piranha580

Is there a big difference between a 3 and a 4 blade prop? I'm toting with the idea of getting a different pitch prop at the mo for some better pick up.. But I also see there's a choice of a 3 or 4 blade too! Would you lose out on top end with a 4 blade??
Cheers
Mark

Yes you will loose on top end with a 4 blade prop, but not lots, maybe about 1-2 knts ish.

[rik_elliott]

With regards to stainless steel semi cleavers, a power tech prop really did transform my cat hulled sib. But I had been getting awful probs with cavitation with the standard bunny prop which was making it pretty unusable. I was running the props shallow as my boat has a slightly dodgy transom design. If you are getting on ok with your ally prop I'd not change - it was really pricey. If it's worked fine but slight cavitation on pick up could always see if steeldevelopments can put some cup on your prop whilst they repair it? Best of luck anyways

[martini]

Originally Posted by piranha580

Is there a big difference between a 3 and a 4 blade prop? I'm toting with the idea of getting a different pitch prop at the mo for some better pick up.. But I also see there's a choice of a 3 or 4 blade too! Would you lose out on top end with a 4 blade??
Cheers
Mark

If you want a prop for pick up, go for a 4 blade rather than a lower pitch 3 blade, the difference is quite surprising. Bear in mind if you do, you will need to lower the pitch by a couple of inches anyway to compensate for the extra blade.

[PeterM]

On the same sort of set up I wouldn't bother - not enough HP to notice the differance in price ...mics 13inch pitch which covers most stuff I do . The slowness to pick up I think is due to 'only' have 50 hp trying to shift more weight ( in % terms on weight of boat probably ALOT of % more compared to a 7m RIB with an extra 3 people . ) .

I have swapped stainless for alloy on the 200hp merc and it cavitates MUCH quicker & loses about 8knts on top end speed .