Ughhh...I'm under-propped

[AsLan7]

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Yup
Good news is she's running amazingly well. Conditions were so smooth that it was easy to open her up. Hit 60 easily and then dismay set in as I heard the dreaded beep--which I thought was the overheat alarm. No!!!

But while analyzing the temp and instruments, I noticed everything was reading normally. Opened engine hatch and all is well.

Opened her up again and heard the beep. She's reving over 5,000 rpm. At 5,100 the alarm will beep. Throttle back and she's fine. On prior tests it was slightly rough so she would hit 63-65 while "unsticking " from the water. But throttle was being jockeyed. Today, it was just full forward since it was so smooth.

24" pitch. 1.81 ratio B3 Drive.

That being said, she is a beast on the water--especially with Captain's call wide open.

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[Big Block Power]

Is 5k max on yours?
Who was in the boat with you. How much gas did you have. Because if you run heavier normally do you really want to go to 26 pitch? Your going to drop 400rpms.

[AsLan7]

Is 5k max on yours?
Who was in the boat with you. How much gas did you have. Because if you run heavier normally do you really want to go to 26 pitch? Your going to drop 400rpms.

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The rpm range is 4600-5000 for the HO. She is rev limited at 5150 which is where the "beep" will occur.

Great point on load. It was just me in the boat with full tank and all equipment. Add a few folks and the extra pounds will bring her down from limiter alarm. Would still be interested in 26" out of curiosity. Maybe those could be spares down the road.

[cmattj]

You actually want to touch the rev limiter slightly after holding her WOT for those burst 30 seconds or so.

As we discussed in the other thread for 252 and as you know in "great DA air" you could pull a 26 to 4900 but it may be luggy and be a strain with normal summer conditions and people on board.

It would be fun to try a 26p as I'm the same way and so is BB on Maximizing your boat but I would take a GPS reading first of your phone and it may suprrise you how inaccurate those dash speedometers are.

BTW great shots (loved the wind deflectors on the aircraft next to the wiper blades) and glad to see you out doing work and boating in the same day.. !! that's how you do it!! I may cut work Friday in your honor

[Ytmsn]

How long does it take you to come up on plane from a holeshot? That's pretty cool that you hit those speeds A7. I bumped 53 and backed out of it. I've only been on the water twice since buying, so I need to run it a little more. I have no idea what is on there now but I'll check that out when I get back home.
My buddy at the prop shop will let me take a 24 out to try. I may take him up on it just for giggles.

[AsLan7]

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You actually want to touch the rev limiter slightly after holding her WOT for those burst 30 seconds or so.

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My issue is I have to throttle back as she doesn't just touch the 5150, but stays up there with the beep going off. Never had that issue with my Donzi or Fountain when I would drop my wife off to go get the trailer and I would go back out looking for folks to race.

This 263's holeshot is as good as our 262 was...no issues getting up on plane quickly. She sets you back in your seat.
It was 70 degrees at 600 foot elevation. It would be fun to try 26'ers with a 1/4 tank of gas...all equipment off...and at 50 degrees during a high pressure system. I'll just dream for now. Kind of surprised the gear ratio is so high. Those props are spinning roughly 2,800 times per minute while she's hitting the rev limiter.

[cmattj]

Atta boy..!!
Now your talking like a prop tester!!
Trick is like BB stated.. some borrowed or good used ones would be great to try!

[AsLan7]

Atta boy..!!
Now your talking like a prop tester!!
Trick is like BB stated.. some borrowed or good used ones would be great to try!

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Do you belong to a prop exchange Matt?

[Big Block Power]

Yt you have a Volvo. You don't have 26's Aslan is running Merc.
Aslan just my guess is because your props are polished which they never are on a b3 something may have been tweaked on them. You could also get some cup added to them and would drop your rpm a bit and help your hole shot a bit more. The prop exchange I've heard nothing but good things about it. BBlades is a awesome prop company. Alot of offshore boys use them. They are in my backyard.
Oh the Hill Marine prop exchange not so much. I was told mine were just about ready so send mine in. Well 2 weeks so far still waiting. Not sure if I can call my credit card company and just cancel this from a year ago.lol

[AsLan7]

Yt you have a Volvo. You don't have 26's Aslan is running Merc.
Aslan just my guess is because your props are polished which they never are on a b3 something may have been tweaked on them. You could also get some cup added to them and would drop your rpm a bit and help your hole shot a bit more. The prop exchange I've heard nothing but good things about it. BBlades is a awesome prop company. Alot of offshore boys use them. They are in my backyard.
Oh the Hill Marine prop exchange not so much. I was told mine were just about ready so send mine in. Well 2 weeks so far still waiting. Not sure if I can call my credit card company and just cancel this from a year ago.lol

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thx bbp.

[cmattj]

I did the Bblades try and exchange but then you where purchasing them once the prop was right and tweaked..

I'm not sure now but BB may know their current program..

Only problem with cup is it can bring rpm down with no speed increases for top end but give you great cruising and holeshot.. duo props bite period..
My slip numbers are good and and seems yours are too.

Try before you buy would be great !

I'm with BB ..call Brett at b blades and at least have a chat with him.. it's a different animal with duo props!

[AsLan7]

I did the Bblades try and exchange but then you where purchasing them once the prop was right and tweaked..

I'm not sure now but BB may know their current program..

Only problem with cup is it can bring rpm down with no speed increases for top end but give you great cruising and holeshot.. duo props bite period..
My slip numbers are good and and seems yours are too.

Try before you buy would be great !

I'm with BB ..call Brett at b blades and at least have a chat with him.. it's a different animal with duo props!

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Ok, roger that. I winterize tomorrow and the boat goes into hibernation Saturday. I'll put this on my short list in the spring.

[DMillerJD]

Hi All! I'm a new member here, and trying to get some prop-sizing info. I have a 2007 Cobalt 232, 496 Mag (not HO, 375 HP) with Bravo 3, 2.0 gear ratio, with 26p props. Boat was originally sold at and used only in Lake Tahoe (elev 6229). I live in the SF Bay Area, and have only had the chance to use it in Lake Berryessa and Folsom Lake (elev 450'). The first day I had it out (last October), I had 7 people on board, food, gear, skis, surf board and 2-person tube, great hole shot, top speed around 47-50 mph (based on iPhone) at around 4600-4800 rpm. WOT is 4800 rpm on this model. Won't be able to take it up to Tahoe until June or July, so still don't have data on how this boat as configured performs at altitude.

In talking with various people, was told too may different things to reconcile. The best I could glean was that 24p for low altitude would have been the "advised" pitch, and 28p for high altitude. But I have 26p, and don't really feel like buying TWO new sets of dual props!

Prior boat was a 2000 Cobalt 206, 5.0L Penta duo prop. Bought high altitude props, which it definitely needed given the smaller engine, and which I had the opportunity to do side-by-side comps on the props at high altitude.

I'm hoping some of you have practical experience with switching props on this boat. It's so dang easy to do that I'm willing to invest the money. Is there anyone out there who has run this boat/enginge/gear config with 30p at low altitude, 26p at high altitude?

Sorry for the long post! Thanks in advance for all your thoughts and experiences! (Can't figure out how to post pic to show her off!!)

[Big Block Power]

Ok matt and I replied to a exact same thread awhile ago. Same scenarios. I'm a bit confused at sea level your at almost 4800 wot? With 26 and max wot is 4800?
And you boat both sea level and high alt?
No matter what you will need two sets of props correct.

[cmattj]

Ok matt and I replied to a exact same thread awhile ago. Same scenarios. I'm a bit confused at sea level your at almost 4800 wot? With 26 and max wot is 4800?
And you boat both sea level and high alt?
No matter what you will need two sets of props correct.

Late to the party. 1st off welcome from California too!! Nor Cal Delta!!

So Dmiller.. it would seem by your numbers your actually a sea level set up now as BB pointed out.
( That means it's sounds perfect unless it's banging off the rev limiter)

Get your gear ratio but the 26p is probably where you want to be..

Going higher in elevation reduces power so the lower pitch (24p) becomes more efficient but slower in top end as you already know.. A lot of my pals just suffer through a Tahoe boating day as it's not too frequent and the water temp never gets much above 60. But it is pretty

Right now you show 13 % prop slip which isn't great but not off either.

Go ahead to our new members section and introduce your awesome 232 and yourself to the crew!!
We love pics !!

And take a look at this thread.( one BB and I just touched on)

viewtopic.php?f=35&t=830&p=15945#p15945

It's a Delta boater with a simaler issue and his was optioned "high elevation option"

Welcome pal!!