Fi23 - Bent my prop

[Spiiina 0]

Hey guys, 

Rough day today and it all happened due to poor judgement and before even jumping in the water. Anywho, I have an Fi23 with the 450hp (at sea level) and the prop I currently have is the 16”x15”. Trying to determine if I’d be better off with the 16”x13” 2907 prop. 

Normally with full ballast, 800#s of lead and two people in the boat and one rider, stinger plate @ 10, and 11.2 mph and I’m running at 3400 Rpms. When I drop bow weight, I’ve gotten a nicer wake but run up to 3800rpms.  Too many more people in the boat with full ballast and I’m not even able to make it past 10.7 unless I throw people in the bow.

I’m in a pretty small lake and really don’t need much speed or go long distances. I mostly surf and will do a bit of boarding here and there. Will the 16”x13” give me better efficiency?  I’ve read in posts about the Ri257 that it’s overkill, but there really isn’t going to be a time where I need to be going more than 35mph.  Any opinions on which way I should go? Tempted to pull the trigger on the 2907 and get this one repaired, worst case I can use the 2907 as the backup. 

Any help is appreciated!

Spina

 

[h20king 794]

The 16 X 13 Is perfect with the 450 and 1 1/4" shaft.  It works great on the 409 as well but makes noise with the 1 1/8" shaft

[Spiiina 0]

Awesome, thanks for your help! 

[carguy79ta 67]

I have the 2829 prop on my 257. 16x15 with .075 cup, I also run 1000 lead. It generally does okay. Have thought about getting the 16x13 prop , but havent.

[Tleeah 33]

I second the 16X13 prop.  I have that on my FI 23 with 300# of lead and the 409 (1 and 1/8 inch shaft).  I average around 3500 RPM's.  My RPM's go down if I add more bow weight, usually.  

[Spiiina 0]

So I went with the 2907 and have come have found I’m running higher RPMs. From what I’ve read, every 1” less of pitch requires an additional 200 RPMs regardless of the better low-end power.  I’m no engineer and have no clue if that’s correct, but the logic seems to be accurate as I’m about 400 RPMs over what I was running on my 2829 16”x15” prop. I had the 2829 prop “fixed” after bending it but when attempting to use it I’m getting a lot of vibrations. Was hoping to test it with the same surf/ballast settings to get a true comparison but have to bring the prop back to the shop to see if they can better balance it.  

Anywho, just wanted to give an update and let anyone know who’s expecting reduced RPMs from the 2907 that you may end up with the opposite. @carguy79ta, if you don’t need another prop yet, stick with the 2829 prop for now.  I will follow up once I can compare them with all settings equal. 

Spina

[h20king 794]

Of course the 16 X 13 will run slightly higher than the 16X 15 but it will also push more weight and perform ar elevation.  Get that 16 X 15 up at 2000ft then let me know your thoughts. 

[Spiiina 0]

@h20king I’m sure you’re dead on and I know you know your stuff because I decided to pull the trigger on my Fi after reading all your prior posts.  Forgive me as I’m obviously prop ignorant. The problem for me is I’ll never see anything more than sea level in Florida. Perhaps a minor detail I didn’t mention in the original post. Oh well, you live and learn...and spend money  Thanks for your help!

[h20king 794]

Yep if you would have mentioned that you never see elevation  I would have suggested you stay with the 16X15