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champ
02-19-2015, 06:03 PM
I think I am becoming a propaholic. As per my last post, in question was a 14x25 left hand long hub stainless steel Volvo Penta prop on ebay. A few responses said that it was not ultra prop. Can anyone describe to me what makes an ultra what it is? shape, size, pitch and part numbers to look for? Why is it coveted so much, and was it ahead of its time?
At any rate, I did by this ebay prop and will put it on to see what it does. Below are pictures, but I wanted to see if anyone can tell me more about it.
Part number is 850952 14x25 L.8150181502

jl1962
02-20-2015, 07:18 AM
I owned a '67 Ski Sporter (302/Volvo) for 8 years and the 24" Ultra was the best prop I owned.

Now a lot of this is subjective but the Ultra had no torque steer, didn't yank the wheel out of my hands, finger light steering, lots of bow lift and was a very fast mid range cruiser with light, manageable chine walk at/near wOT. The 21" Solas probably was a little faster, but my boat didn't like it.

Some say the hubs are weak and can be spun from heavy use, but I never had a problem. They are also pretty rare. I haven't seen one for sale in over a year. I sold my boat a year ago but saved an Ultra just because.....

YMMV

mattyboy
02-20-2015, 08:30 PM
ok a few thoughts the prop you pictured looks like a michigan wheel and looks to be a SS version of an Elephant Ear aka round ear prop the same blade shape and size as their alum offerings elephant eared prop chine walk, porpoise and torque steer on the classic hull

the ultra was made in the 70s for performance they came in even numbers 22 24 26 pitch no odd numbers

the ultra was a very good prop at the time but technology has progressed so the drives and props have changed since then

the ultra is fast and loose fly the nose and will slip like crazy it will also blow out and ventilate in turns or rough water

the hubs are weak but they did have a modification with a michigan hub that was very stout

rules of thumb to use as guidelines

for every inch of pitch or diameter and cupping approx 200 rpms up in pitch or diameter down in rpm and vice versa

for every gear change is just like adding or deleting and inch of pitch from a 1.6 to a 1.5 would be 200 rpm decrease

you want a prop that has good handling and to be at around 10% slip ultra 15% solas 7-8%

you want to spin your motor in its sweet spot where it makes it's power so if it is 5100 5000 4900 5400 rpm you prop to that . I always used 4900 5000 on my setup

you need to know your ratio before you buy any props

so by the numbers you posted going to an ultra 24 would drop your rpms to around 5000 but still have you at just around 50 mph so let's look at spinning an ultra 26 would be 4800 and still right at 50 mph

so now you have bought 2 props and still at 50

the ultra was the best until the solas came along in my book

here is a thread from way back before the solas came out i tested and bought a lot of props once I got the solas I sold them all

Thank You to Randy BiGGrizzly for taking on that project he gave us aq owners a great product, RIP you are missed


here is the thread it should give you and idea of what styles are out there

http://www.donzi.net/forums/showthread.php?43515-winter-discussion-props-and-their-effect-on

mattyboy
02-20-2015, 09:05 PM
sorry one more thought look at the 25 you just bought , if you take the 2 inches increase in pitch and the smaller diameter and just say you will lose 200 instead of 400 rpm going from a 23 to a 25 you are at 4800 rpm and let's be generous and say that prop is at 10% slip gues what you are right at around 50 mph again. you need to check the ratio a 2.0 will seem snappy and jump at the low end but at the high end it is the nash rambler

JimG
02-22-2015, 07:03 AM
Matty captured it well...

For me, the Ultra was the single best mod I ever made to my Donzi. Transformed the boat.

champ
02-22-2015, 10:56 AM
This post mainly for me was to get an idea on what made ultra's so coveted. Also to maybe help others when doing a search for pictures, part numbers, etc. and making a good choice while looking for a prop.
Matty's link to his old post was very informative to say the least, and everyone else's input greatly appreciated.
I have sort of concluded how I have gotten to where I am on this prop/outdrive issue from the information I have received.
1) My boat came with a 22 ultra.
2) The outdrive was changed to a 270, with probably 4 or 6 cylinder gears.
3) Change the gears to 1.61 like suggested.
4) Put the 22 ultra back on.
5) Voila, back to where I started, just with a few extra props.81528

mattyboy
02-23-2015, 10:35 AM
To answer a few questions
They are rare for a few reasons at one time they were only high performance available for the aq volvos people hoarded them. The hubs were weak and if they spun badly they could not be fixed without expensive modifications so some where tossed

Jay has not had a problem with his hub cause the previous owner did looks like jays hub is an upgraded one

Compare to the round ear props the slim blades on an ultra would not torque steer but without a large blade area would slip a lot
With the recent interest in older go fasts new props have been made for the old aq Volvo. Hill is now making a prop they had stopped making decades ago. They can be found on eBay

JimG
02-23-2015, 01:23 PM
I find them on ebay a lot. One just sold for $100 last weekend. I bought my last 14x26LH for a little more than that.

When my hub spun, I took it in and had it fixed by Hood's. No sweat.

Jeff S
02-23-2015, 04:53 PM
I think I am becoming a propaholic. As per my last post, in question was a 14x25 left hand long hub stainless steel Volvo Penta prop on ebay. A few responses said that it was not ultra prop. Can anyone describe to me what makes an ultra what it is? shape, size, pitch and part numbers to look for? Why is it coveted so much, and was it ahead of its time?
At any rate, I did by this ebay prop and will put it on to see what it does. Below are pictures, but I wanted to see if anyone can tell me more about it.
Part number is 850952 14x25 L.8150181502


I have a RH 14X22 Ultra-- the prop in your photos appears to be a stainless version of the stock aluminum Volvo AQ props. PM me if you're interested.

Kirbyvv
02-26-2015, 01:24 PM
I'm guess I'm a hoarder. I have two Ultra 24's and two Ultra 26's. I agree with Jay. The Ultra's improved the handling of my x-18. I also have a Solas 21. I like the Solas alot, but the Ultra's provide more bow lift and just feel looser. I will say the Solas does not blow out and provides unbelievable grip. But I have only blown out the Ultra, when taking a very sharp turn at high speed. the Ultra 24, 26 and Solas 21 all provided about the same top speed.

TXDONZI
03-02-2015, 08:43 PM
I have 2 - 24 Ultras 1 - LH and 1 - RH. I only tried the LH never ran the RH one. My boat at the time was a 21' Kona with a 383 if I remember right it ran 52mph (dash airguide ski speedo) at 5500rpm and 5200rpms with cup. I also have a Michigan 19 and 21 Elephant Ear brass props. The 21 MP seem to run about the same as the 24 Ultra LH if I remember correctly but the steering needed Popeye to take the wheel. The Ultra was much better but still had torque steer. The LH had hub slip after a hard summer of boating and it was bought from a guys as his never used spare. I had it repaired by Baumann Marine, Inc. in the Houston area They said it will NEVER slip again but I have no idea what they did to it hub wise they added cup too.