what gives... prop question

[floater212]

I have a 2005 rinker captiva 21' 350 mpi 300hp xr1 skiing boat, last year I hit an object which tore up the 21" high five prop and chipped the lower gears. had it all fixed like new, but now I didn't have a 21" prop to replace it so I used a 19" 4 blade aluminum. now it doesn't seem as good as the 5 blade was and with all the options and input, my thought is you go down in blades you go up in pitch to stay the same, so under that assumption this 19" would have a better hole shot than the 5 blade, right? not so. actually it seems slower out of the hole.... so now here's the $20 question... does prop diameter have more to do with hole shot than the pitch? smaller high five 13 3/8" compared to the 14 1/4" 4 blade or am I looking backwards at this? I really think I need a 21" high five, even though the owner I bought it from had a 19" high five, the boat is usually full with people waiting their turn so a 19" would be better, so why doesn't the 4 blade 19"work? somewhere on a site online they said " pitch is pitch no matter how many blades or if s/s or aluminum."

 

[steelespike]

Re: what gives... prop question

The High 5 thrives on power and on hole shot. It should have amazing grip, being a ss prop it should out perform
a basic al 4 blade easily.
As pitch increases usually diameter goes down. As you add blades diameter usually goes down.
Comparing the 4blade al prop to a ss high 5 is kind of like comparing a basic Honda to a Corvette.
Both are good solid cars but definitely not in the same class.And comparing numbers would be difficult to evaluate.
It would be interesting to know your wot rpm and gps speed with the high 5 and wot rpm and gps speed with the 19" 4 blade.
And a comparison of a timed hole shot.

 

[steelespike]

Re: what gives... prop question

I apologize; I forgot to welcome you aboard. There is a wealth if information, stem to stern here.
There is help here for the first outboards to the latest monsters.I/Os ,inboards, houseboats, pontoons
etc. etc.

 

[floater212]

Re: what gives... prop question

Since it close to winter I'll have to wait until spring. I'm just looking for someone who went through a similar problem and what did they do to get it right. Some say all props with same pitch does not work the same...find a good one and stick with that brand.

 

[steelespike]

Re: what gives... prop question

While you may find someone with similar problem its unlikely, but we can help you get setup right.
The solution to your problem is a repaired or replaced high 5 if your satisfied with its performance.
There are less expensive ss props that will compare well to the high 5.
there are good al props that will deliver good performance close to that of a ss.
You certainly can't expect a $150 prop to perform like a 500 or$600 prop.
It's nearly impossible to predict results with the type of change you made.
Even going from similar more typical ss to a matching al prop can produce un expected results.
But we can get you setup with what ever prop serves your requirements.
When spring comes you will need a working accurate tach and a gps for speed.
Do some lightly loaded wot test runs with your good al 4 blade.You may be able to get your high 5 repaired depending the damage and the cost. and get us some performance numbers with that.
We need your gear ratio(usually on the out drive),prop size,and the wot rpm and gps speed.
Check out the stickys at the top of the prop forum.

 

[Tail_Gunner]

Re: what gives... prop question

You have a heavier boat and a strong engine. Think of it like this all that weight and hull resistance...the power of that engine....and using alumin as a final gearing material..It is going flex no question. Now the type of prop a 5 blade again lots of metal in the water..and SS not to much flex going on there. In short no 4 blade alumin will hang with a 5 blade ss. In lighter low powered apps one can get away with alum ..in heavier high power...nope.

 

[phillnjack2]

Re: what gives... prop question

the stainless high five will be better than any ali prop.
ali props are cheap and will do for those not wanting performance, their price alone tells the story.
now aluminium is not only weasker and will flex where a stainless will not, the cheapo prop is not even close to the quality of workmanship that goes into the s/steel props.
the alloys are just cast quick clean up spray and put in a box, the stainless ones get poilished weighed balanced and trued a lot more.
youl find little varience if any in the high 5 props, but with ali props you can have two brand new same make and they will be different in some way.
you get what you pay for, and those 5 blade stainless take a lot to beat them for the right application.

aluminium is rubbish compared to stainless, get the right prop .
.