Maximum inboard prop diameter

Tlew · #1 03-06-2015, 06:29 AM

Anyone know for sure?
I know they "growl" a little but want to maximize efficiency.

joshz · #2 03-06-2015, 10:12 AM

I ran a 16" on my old 23. I think the stock one was 16 x16. I don't think you could run a 17" wheel as its to close to the tunnel and would cause cavitation and a bit of noise. The CC26's run a 17" but the tunnel is much bigger or wider and the shaft angle is slightly different. The 26's also had a cavitation issue with some noise also did not like to turn to port at speed.

Tlew · #3 03-08-2015, 04:51 PM

I managed to get the prop from the previous owner, 17 x 17 3 blade. I now have a starting point.
So. I am really close to the engine decision. I believe it will be the PCM 409hp beast.
Prerequisites were, fast and clean. I really like the cooling system on the PCM. KISS theory!
I want to be able to "loaf" along at about 25 knots without a horrendous fuel burn, but have a little sumtin under the hood for when one of those pesky outboard fellas pull alongside.
Did i mention fast?

fat2nawilly · #4 03-11-2015, 09:17 PM

i run a 17x15 with some cup on mine and it does very well, plenty of clearance to hull.

Tlew · #5 03-12-2015, 05:15 AM

If you dont mind me asking, would you share your gear ratio, HP of motor and cruise/WOT numbers please?

pelican · #6 03-12-2015, 08:45 AM

Quote:

Originally Posted by Tlew

I managed to get the prop from the previous owner, 17 x 17 3 blade. I now have a starting point.
So. I am really close to the engine decision. I believe it will be the PCM 409hp beast.
Prerequisites were, fast and clean. I really like the cooling system on the PCM. KISS theory!
I want to be able to "loaf" along at about 25 knots without a horrendous fuel burn, but have a little sumtin under the hood for when one of those pesky outboard fellas pull alongside.
Did i mention fast?

power will have to be increased exponentionally to gain speed...

there's no way a 23 inboard will run with the go fast outboards,such as the contenders,yellowfins and jupiters - ain't gonna happen...

smart move:

repower with a new merc 5.7 horizon,use a 1.5:1 zf gear and be done with it

it's gonna prove to be reliable and incredibly fuel efficient

the boat will run a real good speed with that power - and the best part:

it's an easy install/set up

if you want to run with the fast outboard rigs - get one

trying to make that inboard run with them is going to be like finding bigfoot - a dream...

Tlew · #7 03-13-2015, 05:37 AM

I'm not sure about running with the new go fasts. I want to see a solid 40. Fast for an inboard.
I will routinely carry 5-6 people and a large cooler of water/beer!
The Sea Craft 23 inboard was fairly popular here. For a small island, I can count 4 without thinking about it much. I know 2 for sure have inboard Volvo Diesel and are pretty tired.
None are restored.
I'm trying to be a little different. My nature!

Miles Offshore · #8 03-17-2015, 05:07 PM

I ran a 17-17 for a while on mine but the old 260 hp was just not enough to spin it in the proper rpm range. Also tried a 4 blade 16 i believe and that was a waste of a grand too! Lol. Worked my way back to i think im turning a 16-15 now and that worked great with the old motor. Going with a new vortec this time so i will see how it does with an extra 50 ponys.

fat2nawilly · #9 03-17-2015, 08:35 PM

Ive got a fuel injected marine power 350 with 315hp and a 1.5-1 zf gear, cruise anywhere from 20 to 27mph depending on seas, seas here on the cape are generally crappy and the boat will cavitate a lot if you don't bump it down. if you want to run 40 go with the outboards

Tlew · #10 03-18-2015, 05:22 AM

That cruise sounds great. What wheel are you running?