Props aluminium v Stainless

[chris69]

Found this vid on prop testing and theres all the stats at the end I’m looking a new prop and was thinking stainless and if there worth it and this helped me make my mind up I’ll stay with ally yes the stainless saves some fuel but only in the upper rev range and I don’t run at max rpm.

[Dignity]

Found this vid on prop testing and theres all the stats at the end I’m looking a new prop and was thinking stainless and if there worth it and this helped me make my mind up I’ll stay with ally yes the stainless saves some fuel but only in the upper rev range and I don’t run at max rpm.

That would have to be one of the worst tests I've seen, no stat's at all in reality. The testing should have been done in both directions, with the tide and against also into the wind and with it. I've done it with a number of props and on several boats the same day and surprising what the results show. All detailed at a number of different rev ranges.
Currently running an alloy on my 130hp and damaged it recently on sunken structure, lots of crap moves around the northern end of the Passage. Replacement value $195, similar damage to a SS I had previously and repair well over $250 and replacement more like $750.

I'll stick to the alloy as cheap enough to carry a spare.

[chris69]

There were stats around the 10 minute mark speed and fuel .

Yer I’ve bent a shaft in the past and would think that having a stainless would just push more damage further in the gearbox ,I was more curious on how the efficiency difference was between the 2 and after looking at the comparisons at cruising revs there wasn’t any difference .

[Flex]

stainless is no increase risk than ally for gearbox damage except price replacement.. nearly all stainless props have rubber hubs designed to let go if you hit somthing and save your gearbox. only high level racing boats generally run solid hubs. so your safe there.

As for the test. its terrible IMO.
I would bet most people are unaware of the huge variety of stainless props available and how drastically they can change your boat performance and handing. Even most dealers i have found are clueless or dont care that much.

You cant just slap on a "stainless" prop and expect huge change without knowing what you need from your boat and what model stainless you have.

Do you need bow lift? stern lift? top end speed? holeshot? best cruise economy.prop grip for tight turns? bit of everything? some props can be run at higher engine heights than others depending on the model.
High cup, low cup. long barrel, short barrel, flare, no flare . 3 blade, 4 blade,5 blade, chopper props, large diameter/small diameter. etc

You can literally slap a 3 blade large blade zero flare prop on a boat then test a 4 blade long/flared batter and swear your are in 2 different boats..

Mercury/solas etc has dozens of prop models that can hugely affect boat performance. thats what a true test should be. even suzuki has different models props. eg, their watergrip prop is generally far better cruise speed prop than the standard stainless one.

stainless has the added bonus of being able to lab finish and garnish even more performance from them if you wanted to.

if you have a small boat then likely doesnt matter.
But if you run offshore or do bar work. research prop models. especially from mercury

[Spaniard_King]

That would have to be one of the worst tests I've seen, no stat's at all in reality. The testing should have been done in both directions, with the tide and against also into the wind and with it. I've done it with a number of props and on several boats the same day and surprising what the results show. All detailed at a number of different rev ranges.
Currently running an alloy on my 130hp and damaged it recently on sunken structure, lots of crap moves around the northern end of the Passage. Replacement value $195, similar damage to a SS I had previously and repair well over $250 and replacement more like $750.

I'll stick to the alloy as cheap enough to carry a spare.

Prop prices are rediculas, just got quoted a bush replacment on a V6 this week was $230. GTood luck finding anyone that repairs staino props these days

[chris69]

I put a pandora x5 prop on today $220 on the web site and walked out with a new prop for $170 11.3/8 dx14 p and after playing with it today I can get nearly 2 extra knots and it seems to plain a bit quicker for less revs so I’m happy with it it will be just right in the dams loaded.

[ranmar850]

Use the Mercury type props wiht the Flo-torque hubs and you never need to replace a bush again, that rubber bushing design idea is really out of date. Strip a rubber bush in a remote area and you are screwed, carry a spare flo-torque, which weigh nothing in a small package, and a spanner to get the prop nut off, you can do it in a few minutes. The only downside to SS is the possible transference of damage to the lower unit, it's a lot harder than ally. Will the hub take care of that? Dunno, but I hit a turtle about three years ago at 20knots. He surfaced right under the bow, so close I only glimpsed his head popping up, yanked the throttle back but effectively hit him with power on. There was a hideous vibration as we slowed, turned out to be a large chunk of carapace embedded on a blade. Took it off, everything seemed fine, and no indications of damage in the several hundreads of hours done since. Time will tell.