Prop Help

[Mckillop]

We finally got the 18C wet after an extended restore. The boat now has a 385hp 383 stroker with a new style swept back B1. Just curious what other people with similar power on an 18C are running for a prop. We did a wet test and tune today with the guy who rigged the boat and ran my 23P Mirage Plus. Although we didn't run the boat very hard, nor open the throttle wide open for more than a few seconds, the prop still didn't feel quite right. Anyways, before we do any real prop testing, just wondering what other peole recommend we tart with. Any suggestions?

[pipnit]

what made you feel like it wasn't right?

I suppose this all depends on what your engine can turn RPM wise and what you want it to turn. I have a 383 with more power than yours but run a 23p quad four and it's a nice fit. I think the 23 is going to be a good starting point. You'll have to see what she swings wide open and trimmed out.

[Mckillop]

The problem was we had 4 adults in the boat and a full tank of fuel. Obviously not the best prop testing conditions.lol When we did give a short burst we only saw 4300 rpm.

[pipnit]

Yeah, that's a pretty big load for testing conditions :)

Was the engine still gaining RPM before you backed off? Mine takes a few to get up all the way and then if she's not trimmed, I can get another 2-300 rpm by trimming her properly. I'm swing a quad 4 23P on a TRS 1.5:1 and will get 73mph + on the GPS depending. At 15% slip and assuming you have a 1.5:1 ratio, you should be seeing low 50's at 4300. Any idea how fast she was going? I'm guessing my motor is around 500hp. BTW, I think my TACH is greedy and I'm likely spinning more than 5200 but that's what it indicates. Maybe I have a magic prop :)

[MOP]

IMO you will be needing a bit more prop, John with the red 18 has a fairly warm 350 swings a 3B 24" Stiletto he cranks 70. I have a 22 with a similar HP 383, my best prop is a 4B 23" I run 65.5. I am guessing maybe a 25" will be much closer for you.

[osur866]

You didn't mention gear ratio on the drive, I'm guessing 1.5 but....., I had a 320 HP 383 with B1 with 1.65 gears and my best prop was a 25p M+, with 4 adults and full fuel if your tach is right ill bet a 25p M+ with only you lite on fuel will get you 72-73ish spinning It at about 4,900-5000 (tel:900-5000) RPM's, add full steering, shortie and you could see a few more and much improved handling.

[mike o]

6.2L 320hp B1 / 1.65 :sombrero: Boat came with a Mirage +25P.
I prefer a Laser II 25p because I find it more stable with less dancing :propeller: aired out @ 68-70 than the Mirage +. :yes: I cut the stops on the bennets :cards:

[osur866]

6.2L 320hp B1 / 1.65 :sombrero: Boat came with a Mirage +25P.
I prefer a Laser II 25p because I find it more stable with less dancing :propeller: aired out @ 68-70 than the Mirage +. :yes: I cut the stops on the bennets :cards:

Mike yours needs a huffer on it next ;)

The shortie would help with some of the dancing as well

[championsportsnow]

Best prop i found for classic 18 is a Fury 24 stainless prop