My 28 partycat is getting repowered right now with a 600SC. The engine that came out, 7.4 merc, had 385hp. The boat has a bravo III with 24 pitch props on it. Im looking at a couple of used props and I am stuck between a 28p and 30p props. I know that the 30 (cupped) is a big jump, but the boat only ran about 55mph with the 7.4 and the hull is just starting to perform at that speed.
what to do? go with the 28p and have them redone if not enough or 30p and hope the damn thing will even get on a plane?
Deano,
The 30p is a really big jump from what you have now. It is also going to put a lot more stress on your outdrive. Being a deck, I'm sure there are times that have got a bunch of people on it. As you stated ,it might make it a bit hard to get on plane with the 30p. I think that the 28p would be a better suit to a deck with the bIII. The 28p will still give you a really big improvement.
Darrell.
BTW, who it the manufacturer of your boat?
Darrell.
28p
Advantage 28'r. I wired the guy 450.00 for the props (30p) about an hour ago.
The props are new and a good deal. I'll run em for the weekend and see what happens. I might bring them into hill and have them reworked if needed.
The boat has tabs on it that will help alot. Ill let you guys know what happens. Thanks for the input.
DEANO,
I'm actually running the same hull design. I have a 28ft Advantage Sport Cat.
I'm running twin motors so unfortunatly the set up is apples to oranges. Sorry I couldn't help more on yours. For what it is worth, I'm changing back to larger props for my boat. I called Advantage and spoke with Bob Wilsey. Thier techinical guru and customer service guy. What a gentleman. VERY VERY friendly and helpfull. It might be worth a call. The good news is if the 30's don't work out for you, they can always be re-pitched. Good luck, hopefully they will work-ouy for you. Keep us posted.
Darrell.
yea, Its going to be a trial and error thing. There are alot of variables that need to be considered. the other props would have me bouncing off the rev limiter (5K) with two people and gas. I couldnt even get it to 5k with 10 people, coolers, etc..
Looking/reading about similar set ups leads me to believe that I can get low 70s. For the boat to be over 70mph (according to prop calcs at .15 slip) 5,200 rpm limit, I need a cupped 30p.
I am also installing a intercooler after this season so Ill pick up a few more ponies.
Ill let you know how it goes...
Just to let ya know. The motors in my boat started out as 600SC's. Bob Wilsey told me that after adding the Supperchillers and pullies only, they dyno'd out at 750hp!!! Pretty big gain. They have since been taken up to 800's with cams and such.
Just to let ya know. The motors in my boat started out as 600SC's. Bob Wilsey told me that after adding the Supperchillers and pullies only, they dyno'd out at 750hp!!! Pretty big gain. They have since been taken up to 800's with cams and such.
Nice,so how does your 28' sport cat run with 2 800's....
Nice,so how does your 28' sport cat run with 2 800's....
Well, the boats still pretty new to me. Still getting use to it. Also it is under proped right now, running 30p Bravos. I've seen 110 on it with 100 gallons fuel and 2 people, and it still had more to go. Ran out of river, (or mabey balls). Bob Wilsey at Advantage, who set the boat up says he has been over 130 with 32p Bravos. I am going to reprop, up to 32 or 34p Bravos .I think it has more than enough hp for 34's with the boats weight. May decrease cruise rpm nicely. Have to see. I wish it was less trial and error for prop selection.
Darrell.
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