Prop aq151 volvo 19.5 cuddy

[robjen1019]

Currently I have a 15 in 19 pitch aluminum prop. Boat runs at 5100 rpm at a top speed of 35mpg, by gps. Manual states optimum is 5200 to 5500 rpm Fom what I can tell it is a standard prop with little to no cupping
I am looking at getting a ss prop. The only one available for my 290 outdrive is the solas titan. the Titian is 15 5/8 inches in diameter. Im wondering what pitch to go with. I was initially thinking for 17, but not sure to do with the added diameter. Do I go all the way down to 15?

Any input would be much appreciated.

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

What is the gear ratio of your drive.

H

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

2.15:1

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

Tell me the boat information. Year, manufacturer, model and base weight as well as the horsepower of the motor. Right now your Prop Slip is at 18% and if this is a heavy boat with everything included you might want a zerro rake prop to raise the stern instead of a high rake prop that raises the bow. Also how many degrees of deadrise (vee) is in the hull.

H

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

The boat is a 1988 sunrunner 195 cv. The v in the boat is a pretty steep. When it is running through the water it does come up pretty good in the front. Ive got Trim tabs on, but still comes up quite a bit.
Motor has 150 hp The boat feels pretty heavy, at least that is what my pickup tells me when I pull it.

Wonder if I would be better with a 4 blade prop instead. iboats doesn't have any in ss, but they do have an aluminum one.

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

Rob, I find your boat to have a base weight of 2,150 pounds and an allup weight with my guesses at 3,100 pounds. You currently have a slip of 18% prop slip, and my opinion is you need to have a 4 bladed prop to reduce the prop slip. My recommendation is a Solas Amita 4 blade aluminum prop with a Diameter of 14.5" and a Pitch of 17" and that should increase midrange and reduction of prop slip as well. I expect it to turn approximately 5,400 RPM at a speed of about 37 MPH. My calulations show more RPM, but dont take into acount the reduction in Diameter and the increase in the 4th blade. I am sorry I don't know which prop to pick for stainless, but in my opinion you need zero rake for stern lift instead of anything above that in rake that will just give you bow lift and in my opinion you need stern lift more than bow lift.

Boat and Motor

Prop Change

But I am sure other people have different opinions.

H

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

I think I am going to order the 4 blade, about half the price of ss.

thanks for the input.

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

You are welome Rob, please let me know the WOT RPM and Speed for my database.

H

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

Prop update,
195 Sunrunner Cuddy
aq 151 145 hp
290 outdrive
4 Blade solas aluminum Long hub 14.5x17 pitch right hand
top speed 32mph @ 5100 rpm



Seems a little funny though, Gains good up to 4500, but from 4500 to 5100 only gains about 3 to 5 mph.

Plains out at about 3800 rpm, then I can back it off to 3100 and keep on plain.

Definitely easier to handle around the dock with the 4 blade, especially in reverse.

I wish I would have gone with a left hand with 15 pitch. would have put me in the 5300 to 5400 rpm range.

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

Iboats does exchanges on props call them.

H

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

Rob, it appears to me something is wrong, you should be getting full RPM out of that prop. With the motor turned off push the throttle all the way forward and look in the carburetor and make sure the butterfly is fully open, then check for spark to all spark plugs. You ought to be getting 5,400 out of that prop, yet you are getting the same RPM as the 19" Pitch. Please check these items.

H

 

[hwsiii]

Re: Prop aq151 volvo 19.5 cuddy

Rob, I went back and looked through all of my calculations, from what your results show it appears that even with a 1/2" reduction in diameter and a drop of 2" in pitch you gained no RPM by changing to the solas amita with the 4 blades. Not only that but you lost 3 MPH at WOT and did not gain but 2% in prop slip from 18% to 16% with the amita.
Your 3 blade aluminum 19" is definitely outperforming the amita in top speed, and the trim tabs you have on it are evidently holding the stern up without the need for a 4 blade prop, changing to a 15" amita will raise the RPM but I see no advantage over a standard 3 blade aluminum 17" pitch, other than a better hole shot and midrange cruising speed as well as a lower planing speed but having to exchange that for a lower top speed and you didn't mention anything about needing more hole shot. But you didn't say anything about wanting or needing those particular attributes. Quite frankly I forgot that you already had trim tabs on the boat and if everything is right with the motor then I made a mistake by recommending the solas amita for your application, because it did not reduce the prop slip hardly any and you lost 3 MPH in top speed. It is my mistake and I am sorry, if you bought the prop from Iboats my understanding is they have an exchange program

H

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

Don't sweat it, I really like the 4 blade much better than the 3. The low speed menoviering is much better. When I was docking it yesterday, it was so much easier to control. Both my 3 blades are pretty beat up. I use the boat mostly for pulling kids on tubs and kneeboards, so low end is very important. As for top speed. most days, anything faster than 25 is too fast for my wife.

Im thinking Ill run this one this summer and get a ss next spring.

 

[robjen1019]

Re: Prop aq151 volvo 19.5 cuddy

Update:

Ran a Solas 4 blade 14.75 x 15 pitch. boat seemed to have more power out of the hole, but My Rpms were only slightly higher.
It ran about 5100 rpm at full throttle, I didn't have my gps, so I don't know about top speed.

compared to my other prop, its just marginaly different.

solas 4 blade 14.5 x 17 pitch ran 32mph at 4900 to 5000 rpms.

I was expecting a little more change in rpms. Im going to check the top speed next time out.

I did check the throttle and it is opening all the way up.

 

[dazk14]

Re: Prop aq151 volvo 19.5 cuddy

Robjen, I know this post is a year old, but I was wondering if you had any more data on your setup(if you're still out there).
I'm trying to prop an AQ 151 on the 20'6" Sunbridge.
Thanks!